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Aims: To determine whether the risk of psychotic symptoms during weeks of methamphetamine use was dependent on, increased by, or independent of having a family history of psychosis., Design: Secondary analysis of 13 contiguous 1-week periods of data (1370 weeks). A risk modification framework was used to test each scenario., Setting: Geelong, Wollongong and Melbourne, Australia., Participants: Participants in a randomized controlled trial of treatment for methamphetamine dependence (n = 148) who did not have a primary psychotic disorder on enrolment., Measurements: Psychotic symptoms in the previous week were defined as a score of 3+ on any of the Brief Psychiatric Rating Scale items of hallucinations, unusual thought content or suspiciousness. Any (vs no) methamphetamine use in the previous week was assessed using the Timeline Followback method. Self-reported family history of psychosis was assessed using the Diagnostic Interview for Psychosis., Findings: The risk of psychotic symptoms in the past week was independently associated with methamphetamine use in that week (relative risk [RR] = 2.3, 95% CI = 1.3-4.3) and with having a family history of psychosis (RR = 2.4, 95% CI = 0.9-7.0); the joint risk among participants with a family history of psychosis during weeks when they were using methamphetamine was large (RR = 4.0, 95% CI = 2.0-7.9). There was no significant interaction between a family history of psychosis and methamphetamine use in predicting psychotic symptoms (interaction RR = 0.7 95% CI = 0.3-1.8), but there was a small non-significant excess risk due to the interaction (0.20 95% CI = -1.63 to 2.03)., Conclusions: Among people dependent on methamphetamine, the relative risk of psychotic symptoms during weeks of methamphetamine use does not appear to be dependent on, or increased by, having a family history of psychosis. However, a family history of psychosis does appear to be an independent risk factor that contributes to the absolute risk of psychotic symptoms in this population., (© 2023 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Background and Aims: Few studies of the impacts of the coronavirus disease 2019 (COVID-19) public health measures on drug markets and drug use patterns have used longitudinal data. We aimed to examine whether COVID-19 measures were associated with increases in methamphetamine price, decreases in methamphetamine use frequency and subsequent changes in secondary outcomes of other drug use frequency in metropolitan Melbourne and regional Victoria., Design: Longitudinal analysis framework was used from a longitudinal cohort of people who use methamphetamine., Setting: Victoria state, Australia., Participants: One hundred eighty-five VMAX study participants who reported a methamphetamine purchase after the onset of the pandemic were used for the price paid analysis. Methamphetamine or other drug use frequency analysis was performed using 277 participants who used methamphetamine during the pandemic or in the year before the pandemic., Measurements: Price paid per gram of methamphetamine derived from the most recent purchase price and most recent purchase quantity. Frequency of methamphetamine and other drug use measured as the average number of days per week used in the last month., Findings: Compared with pre-COVID-19 period, methamphetamine prices increased by AUD351.63 (P value <0.001) and by AUD456.51 (P value <0.001) in Melbourne and regional Victoria, respectively, during the period in which the most intense public health measures were implemented in Victoria. Although prices decreased after harder restrictions were lifted (by AUD232.84, P value <0.001 and AUD263.68, P value <0.001, in Melbourne and regional Victoria, respectively), they remained higher than pre-COVID-19 levels. A complementary 76% decrease was observed in relation to methamphetamine use frequency in regional Victoria (P value = 0.006) that was not offset by any changes in the frequency of use of other drugs such as alcohol, tobacco or other illicit drugs., Conclusion: COVID-19 public health measures in Victoria state, Australia, appear to have been associated with major price changes in the methamphetamine market and decreased frequency of use of the drug., (© 2023 The Authors. Addiction published by John Wiley & Sons Ltd on behalf of Society for the Study of Addiction.)

Aim: To test (1) if there was a change in self-reported lifetime prevalence of meth/amphetamine use by birth cohort and (2) if the extent of under-reporting of meth/amphetamine use was associated with the proportion of the population who nominated meth/amphetamine as a drug problem., Design: Observational study using seven waves of repeated cross-sectional nationally representative household surveys between 2001 and 2019., Setting: Australia., Participants: Participants were from three birth cohorts: 1951-60 (age 68-77 at the 2019 survey; n = 29 458; 55% female), 1961-1970 (age 58-67; n = 29 859; 57% female) and 1971-1980 (age 48-57; n = 28 758; 59% female). Data were weighted to align the sample to the Australian population., Measurements: Past year meth/amphetamine use; under-reporting of lifetime meth/amphetamine use in each birth cohort, year and survey stratum (operationalised as the difference between self-reported lifetime prevalence in 2001 and that of each subsequent year); proportion of the population who nominated meth/amphetamine as a drug problem in each birth cohort, year and survey stratum. Under-reporting was regressed on the proportion of people holding negative attitude towards meth/amphetamine. Survey year and birth cohort were adjusted for., Findings: Between 2001 and 2019, the lifetime prevalence of meth/amphetamine decreased from 6.1% (95% CI = 5.3-6.9) to 1.7% (95% CI = 1.2-2.2) in the 1951-1960 birth cohort (p < 0.001), from 13.0% (95% CI = 12.0-14.1) to 4.4% (95% CI = 3.7-5.2) in the 1961-1970 birth cohort (p < 0.001) and from 21.4% (95% CI = 19.9-22.9) to 11.2% (95% CI = 10.0-12.4) in the 1971-1980 birth cohort (p < 0.001). The proportion who nominated meth/amphetamine as a 'drug problem' increased significantly in all three cohorts (all p < 0.001) and the degree of under-reporting of meth/amphetamine use was significantly associated with proportion of people who nominated meth/amphetamine as the 'drug problem' (b = 0.09, SE = 0.01, p < 0.001)., Conclusion: In Australia, the actual prevalence of lifetime meth/amphetamine use may be two- to fourfold higher than that estimated in the most recent national household surveys (2019). The level of under-reporting is strongly associated with increasing negative attitudes towards methylamphetamine and d-amphetamine use over the same period., (© 2021 Society for the Study of Addiction.)

Background and Aims: Few longitudinal studies have examined the relationship between food insecurity and substance use. We aimed to investigate this relationship using longitudinal data among women with or at risk for HIV in the United States., Design: Women's Interagency HIV Study (WIHS), a prospective cohort study., Setting: Nine sites across the United States., Participants: A total of 2553 women with or at risk for HIV., Measurements: Semi-annual structured interviews were conducted during April 2013-March 2016. Food security (FS) was the primary predictor, measured using the Household Food Security Survey Module. Outcomes were: any illicit substance use except cannabis; licit or illicit cannabis use; stimulant use (crack, cocaine, or methamphetamine); opioid use (heroin or methadone in a non-prescribed way); and prescription drug misuse (prescription narcotics, amphetamines, or tranquilizers in a non-prescribed way) since the last visit. We used multivariable logistic regression with random effects to examine longitudinal associations of current and previous FS with the outcomes simultaneously, adjusting for socio-demographic factors, HIV serostatus, physical health and health insurance., Findings: Average number of visits was 4.6. At baseline, 71% of participants were HIV-seropositive, 44% reported marginal, low, or very low FS, and 13% were using illicit substances. In adjusted analyses, current low and very low FS were significantly associated with 1.59 [95% confidence interval (CI) = 1.02, 2.46; P = 0.039] and 2.48 (95% CI = 1.52, 4.04; P < 0.001) higher odds of any illicit substance use, compared to high FS, and also with higher odds of cannabis, stimulant and opioid use, exhibiting a consistent dose-response relationship. Marginal, low, and very low FS at the previous visit were associated with 1.66 (95% CI = 1.08, 2.54; P = 0.020), 1.77 (95% CI = 1.14, 2.74; P = 0.011), and 2.28 (95% CI = 1.43, 3.64; P < 0.001) higher odds of current illicit substance use., Conclusions: Food insecurity appears to be longitudinally associated with substance use among US women with or at risk for HIV., (© 2018 Society for the Study of Addiction.)

Background and Aims: Non-medical use of prescribed stimulant medications is a growing concern. This study's aims were to ascertain the demographics of stimulant medication users compared with non-users, examine temporal trends of stimulant medication use and estimate risk factors for development of amphetamine use disorder (AUD) and mortality among new users of stimulant medications., Design: Cox proportional hazards regression in a retrospective cohort adjusted by baseline covariates., Setting: United States, national administrative database of the Veterans Affairs (VA) health-care system., Participants: Adult incident users of stimulant medications (n = 78 829) from fiscal years (FY) 2001 to 2012., Measurements: Primary outcomes were time-to-event: (1) occurrence of AUD diagnosis and (2) death. Baseline covariates included demographic information, Food and Drug Administration (FDA)-approved indications for stimulant use, substance use disorders (SUD) and depression., Findings: Stimulant users compared with non-users were younger, more likely to be non-Hispanic white and female. Incident stimulant medication users increased threefold from FY2001-FY2012 and eightfold among adults aged 18-44 years. Nearly one in 10 incident users in FY2012 had a comorbid baseline SUD. Off-label use was common-nearly three of every five incident users in FY2012. Comorbid SUDs among incident stimulant medication users were risk factors for occurrence of AUD during follow-up, with adjusted hazard ratio (AHR) estimates ranging from 1.54 to 2.83 (Ps < 0.05). Increased mortality risk was observed with occurrence of AUD during follow-up [AHR = 1.55, 95% confidence interval (CI) = 1.13-2.14, P = 0.007], while on-label prescribing was protective against death (AHR = 0.686, 95% CI = 0.63-0.75, P < 0.0001)., Conclusions: In a US national cohort of adult incident stimulant medication users in the Veterans Affairs health-care system, measured from fiscal years 2001 to 2012, comorbid substance use disorders were common and were risk factors for development of an amphetamine use disorder (AUD). Increased mortality risk among incident users of stimulant medications was observed among both those who developed an AUD later and those whose use was defined as off-label., (© 2017 Society for the Study of Addiction.)

Aims: To examine the mortality risk in a cohort of 'hard-to-reach' polysubstance users and its putative associations with substance use. Specifically, we estimated all-cause mortality risk as a function of individual substance use indicators, and then as a function of their complex, 'real-life' patterns as identified through latent class analysis (LCA)., Design: Prospective cohort study among street- and low-threshold service-recruited polysubstance users included between September and November 2013 and followed through the National Cause of Death Registry until 31 October 2015., Setting: Seven Norwegian cities., Participants: A total of 884 users of illegal opioids and/or stimulants. Of these, 357 were in opioid substitution treatment (OST) at the time of inclusion. Forty-four participants died during follow-up., Measurements: Primary outcome: all-cause mortality risk. Unadjusted and adjusted Cox proportional hazard (PH) regression models (covariates: male, age, homelessness/shelter use, overdose experience, OST status, years of injecting, individual substance use indicators, city, use patterns). LCA models estimated separately for those in and those not in OST due to measurement invariance., Findings: The crude mortality rate was 2.52 per 100 person-years. Standardized mortality ratio was 26.11 [95% confidence interval (CI) = 10.06-54.87] for women and 10.71 (95% CI = 6.39-16.81) for men. No single drug use indicator, such as 'heroin injection' or 'number of drugs used', was associated with the mortality risk. However, meaningful use patterns were identified; three OST and non-OST patterns each. The non-OST patterns 'polysubstance injectors' [hazard ratio (HR) = 3.45, 95% CI = 0.98-12.14] and 'low frequent injectors' (HR = 3.17, CI = 1.05-9.56) were associated significantly with the mortality risk even when adjusted for other known risk factors., Conclusions: In a Norwegian prospective cohort study, 'hard-to-reach' polysubstance users had a more than 10 times higher mortality risk than the general population. Mortality risk was not a function of any single drug use indicator, but two distinct combinations of substances, frequencies and routes of administration were associated with the mortality risk., (© 2017 Society for the Study of Addiction.)

Background and Aims: In April 2015, the UK government enacted a temporary class drug order (TCDO) on ethylphenidate in response to reported harms associated with its use, in particular an outbreak of infections among people who inject drugs (PWID) in Lothian, Scotland. This study assesses the effect that the TCDO had on reducing the most common infections identified during the outbreak: Streptococcus pyogenes and Staphylococcus aureus., Design: The outbreak was split into a pre-intervention period (35 weeks) and a post-intervention period (26 weeks) based around the date of the TCDO. Segmented negative binomial regression models were used to compare trends in weekly counts of infections between the pre- and post-intervention periods., Setting and Participants: PWID in the Lothian region of Scotland., Measurements: Cases of S. pyogenes and S. aureus infections reported within the National Health Service, Lothian., Findings: There were 251 S. pyogenes and/or S. aureus infections recorded among 211 PWID between February 2014 and December 2015: 171 infections in the pre-intervention period and 51 in the post-intervention period. Significant trend changes in weekly S. pyogenes and/or S. aureus infections following the TCDO were found [relative risk (RR) = 0.88, 95% confidence interval (CI) = 0.82-0.94]. PWID who self-reported using novel psychoactive substances (NPS) were at higher risk of acquiring these infections (RR = 1.81, 95% CI = 1.12-2.93), particularly when comparing the risk of infection with NPS use for a specific strain, S. pyogenes emm76.0, against the risk of infection with NPS use for S. pyogenes (emm types other than emm76.0) (RR = 3.49, 95% CI = 1.32-9.21)., Conclusions: The UK government's 2015 temporary class drug order on ethylphenidate was effective in reducing infections among people who inject drugs during an outbreak situation in Lothian, Scotland., (© 2017 Crown copyright.)

Aims: To understand processes placing individuals at risk for stimulant (amphetamine and cocaine) use disorder., Design: Longitudinal study., Setting: University of California, San Diego Department of Psychiatry, CA, USA., Participants: Occasional stimulant users (OSU; n = 184) underwent a baseline clinical interview and a functional magnetic resonance imaging (fMRI) session. On the basis of a follow-up clinical interview completed 3 years later, OSU (n = 147) were then categorized as problem stimulant users (PSU: n = 36; those who developed stimulant use disorders in the interim) or desisted stimulant users (DSU: n = 74; those who stopped using). OSU who did not meet criteria for PSU or DSU (n = 37) were included in dimensional analyses., Measurements: fMRI blood oxygen level-dependent (BOLD) contrast percentage signal change from baseline collected during a Paper-Scissors-Rock task was examined during three decision-making conditions, those resulting in: (1) wins, (2) ties and (3) losses. These data were used as dependent variables in categorical analyses comparing PSU and DSU, as well as dimensional analyses including interim drug use as predictors, controlling for baseline drug use., Findings: PSU exhibited lower anterior cingulate, middle insula, superior temporal, inferior parietal, precuneus and cerebellum activation than DSU across all three conditions (significant brain clusters required > 19 neighboring voxels to exceed F (1,108)  = 5.58, P < 0.01 two-tailed; all Cohen's d > 0.83). Higher interim marijuana use was linked to lower pre-central and superior temporal activation during choices resulting in wins (> 19 neighboring voxels to exceed t = 2.61, P < 0.01 two-tailed; R 2 change > 0.11)., Conclusions: Individuals who transition from stimulant use to stimulant use disorder appear to show alterations in neural processing of stimulus valuation and outcome monitoring, patterns also evident in chronic stimulant use disorder. Attenuated anterior cingulate and insular processing may constitute a high-risk neural processing profile, which could be used to calculate risk scores for individuals experimenting with stimulants., (© 2017 Society for the Study of Addiction.)

Background and Aims: In December 2006 the United States regulated sodium permanganate, a cocaine essential chemical. In March 2007 Mexico, the United States' primary source for methamphetamine, closed a chemical company accused of illicitly importing 60+ tons of pseudoephedrine, a methamphetamine precursor chemical. US cocaine availability and methamphetamine availability, respectively, decreased in association. This study tested whether the controls had impacts upon the numbers of US cocaine users and methamphetamine users., Design: Auto-regressive integrated moving average (ARIMA) intervention time-series analysis. Comparison series-heroin and marijuana users-were used., Setting: United States, 2002-14., Participants: The National Survey on Drug Use and Health (n = 723 283), a complex sample survey of the US civilian, non-institutionalized population., Measurements: Estimates of the numbers of (1) past-year users and (2) past-month users were constructed for each calendar quarter from 2002 to 2014, providing each series with 52 time-periods., Findings: Downward shifts in cocaine users started at the time of the cocaine regulation. Past-year and past-month cocaine users series levels decreased by approximately 1 946 271 (-32%) (P < 0.05) and 694 770 (-29%) (P < 0.01), respectively-no apparent recovery occurred through 2014. Downward shifts in methamphetamine users started at the time of the chemical company closure. Past-year and past-month methamphetamine series levels decreased by 494 440 (-35%) [P < 0.01; 95% confidence interval (CI) = -771 897, -216 982] and 277 380 (-45%) (P < 0.05; CI = -554 073, -686), respectively-partial recovery possibly occurred in 2013. The comparison series changed little at the intervention times., Conclusions: Essential/precursor chemical controls in the United States (2006) and Mexico (2007) were associated with large, extended (7+ years) reductions in cocaine users and methamphetamine users in the United States., (© 2016 Society for the Study of Addiction.)

Aims: To test if polysubstance use profiles and drug-related outcomes differ between those receiving and not receiving opioid substitution therapies (OST) among people who inject drugs (PWID)., Design: An annual cross-sectional, sentinel sample of PWID across Australia., Setting: Data came from 3 years (2011-13) of the Illicit Drug Reporting System (IDRS)., Participants: A total of 2673 participants who injected drugs from the combined national IDRS samples of 2011 (n = 868), 2012 (n = 922) and 2013 (n = 883)., Measurements: Latent class analysis (LCA) was used to summarize participants' self-reported use of 18 types of substances, with the resulting polysubstance use profiles then associated with participant experience of a number of drug-related outcomes., Findings: Polysubstance use profiles exhibiting a broad range of substance use were generally at increased risk of negative drug-related outcomes, whether or not participants were receiving OST, including thrombosis among OST receivers [odds ratio (OR) = 2.13, 95% confidence intervals (CI) = 1.09-4.17], injecting with used needles among OST receivers and non-receivers, respectively (OR = 2.78, 95% CI = 1.50-5.13; OR = 2.15, 95% CI = 1.34-3.45) and violent criminal offences among OST receivers and non-receivers, respectively (OR =2.30, 95% CI = 1.16-4.58; OR = 1.87, 95% CI = 1.14-3.07). An important exception was non-fatal overdose which was related specifically to a class of PWID who were not receiving OST and used morphine frequently (OR = 1.83, 95% CI = 1.06-3.17) CONCLUSION: Regardless of opioid substitution therapies usage, people who inject drugs who use a broad-range of substances experience greater levels of injecting-related injuries and poorer health outcomes and are more likely to engage in criminal activity than other groups of people who inject drugs., (© 2016 Society for the Study of Addiction.)

Aim: To estimate associations between recent licit and illicit substance use and subsequent suicide attempt among people who inject drugs (PWID)., Design: Secondary analysis of longitudinal data from a prospective cohort study of PWID followed bi-annually between 2004 and 2011., Setting: Montréal, Canada., Participants: Seven hundred and ninety-seven PWID who reported injection drug use in the previous 6 months, contributing to a total of 4460 study visits. The median number of visits per participant was five (interquartile range: 3-8)., Measurements: An interviewer-administered questionnaire eliciting information on socio-demographic factors, detailed information on substance use patterns and related behaviours, mental health markers and suicide attempt. The primary exposure variables examined were past-month use of alcohol [heavy (≥ 60 drinks); moderate (one to 59 drinks); none], sedative-hypnotics, cannabis, cocaine, amphetamine and opioids [regular (≥ 4 days); occasional (1-3 days); none]. The outcome was a binary measure of suicide attempt assessed in reference to the previous 6 months., Findings: In multivariate analyses, a positive association was found among licit substances between heavy alcohol consumption [adjusted odds ratio (AOR) = 2.05; 95% confidence interval (CI) = 1.12-3.75], regular use of sedative-hypnotics (AOR = 1.89; 95% CI = 1.21-2.95) and subsequent attempted suicide. Among illicit substances, occasional use of cannabis (AOR = 1.84; 95% CI = 1.09-3.13) had a positive association with subsequent suicide attempt. No statistically significant association was found for the remaining substances., Conclusion: Among people who inject drugs, use of alcohol, sedative-hypnotics and cannabis, but not cocaine, amphetamine or opioids, appears to be associated with an increased likelihood of later attempted suicide., (© 2015 Society for the Study of Addiction.)

Aims: To investigate the temporal pattern of appearance of a new psychoactive substance (4-fluoroamphetamine) on the Dutch drug market, as well as its patterns of use and effects., Design: Data from the Drug Information and Monitoring System (DIMS) was used to investigate the emergence of 4-fluoroamphetamine on the Dutch drug market. An on-line questionnaire was used to study its patterns of use and effects., Setting: Dutch drug-related websites and social media., Participants: A convenience sample of 249 life-time 4-fluoroamphetamine users was recruited through the internet., Measurements: Samples containing 4-fluoroamphetamine were extracted from the DIMS database for further investigation. Patterns of use, settings of use and the subjective effects of 4-fluoroamphetamine, amphetamine and 3,4-methylenedioxymethamphetamine (MDMA) were investigated with the on-line questionnaire., Findings: 4-Fluoroamphetamine was first encountered on the Dutch drug market, sold mainly as amphetamine or ecstasy (MDMA), between 2007 and 2009. These misrepresented drug samples declined when the MDMA and amphetamine markets recovered after a period of shortage, whereas purposefully bought 4-fluoroamphetamine samples showed an increase. Survey results showed that 4-fluoroamphetamine is used predominantly [77.1%, 95% confidence interval (CI) = 72.0-82.3] for its specific effects, rather than its legal status (17.7%, 95% CI = 10.7-22.1). The subjective effects of 4-fluoroamphetamine were compared with those of amphetamine and MDMA. Subjective effect scores of 4-fluoroamphetamine ranged between those of amphetamine and MDMA., Conclusions: The stimulant 4-fluoroamphetamine is increasingly popular in the Netherlands, which might be due to its subjective effects profile, which lies intermediate between amphetamine and MDMA., (© 2015 Society for the Study of Addiction.)

Aims: To assess systematically the risk of HIV acquisition by type of drug injected across different settings., Methods: A systematic review and meta-analysis were conducted. Databases were searched for studies of HIV incidence in people who inject different drugs (PWID). Pooled HIV incidence rate ratio (IRR) was used to compare HIV risk between injecting and not-injecting a given drug, when possible, or otherwise with those reported not to have injected the substance. Pooled estimates of crude IRR were derived using random-effects models. Variations in IRR were assessed in subgroup analyses, by drug and geographical region., Results: Of 5779 studies screened, 15 were included. HIV incidence was reported for people injecting cocaine (eight: North America, Europe), amphetamine-type stimulants (ATS) (four: Western and Eastern Europe, Asia), heroin (11: all settings), opiate-stimulants (four: North America, Western and Eastern Europe) and opiates-sedatives (five: Europe, Asia). HIV risk in cocaine injectors was 3.6 times 95% confidence interval (CI) = 2.8-4.7, I(2)  = 0%; n = 4) that of non-injectors and 3.0 for ATS injectors (95% CI = 2.2-4.1, I(2)  = 0%; n = 2). Higher sexual risk was reported in cohorts injecting stimulants. Compared to not-injecting, HIV IRR was 2.8 (95% CI = 1.7-4.7, I(2)  = 77%; n=6) for all heroin injectors and 3.5 (95% CI = 2.3-5.2, I(2)  = 40%; n=5) for heroin injectors in Asia and Europe., Conclusion: The risk of HIV acquisition in people who inject drugs appears to vary by drug type but differences are not statistically significant, precluding conclusive grading of risk., (© 2014 Society for the Study of Addiction.)

Aim: To investigate the characteristics of the different club drugs and associated high-risk sexual behaviours in China., Design: Multicentre cross-sectional study., Setting: Drug Detoxification and Rehabilitation Centres in six provinces, China., Participants: A total of 1434 eligible club drug users were included., Measurements: Participants were investigated by trained interviewers using a self-designed structured questionnaire to collect information on club drug use and associated behaviours., Findings: Methamphetamine was the most commonly abused drug in participants (73.92%), who used it in their or their friends' homes by non-injection for the purpose of feeling euphoria. Among participants with sexual behaviours after club drug use, 75.21% reported having engaged in sex with multiple partners after club drug use during the past year and 79.84% had unprotected sex after using club drug during the past year. A two-level logistic model showed that male gender [adjusted odds ratio (AOR)=7.14; 95% confidence interval (CI)=4.17-12.5], unmarried (AOR=1.71, 95% CI=1.04-2.79), long duration of club drug use during their life-time (AOR=1.76, 95% CI=1.28-2.42) and severe acute intoxication after using club drugs during the past year (AOR=2.11, 95% CI=1.07-4.15) were independent risk factors of multiple sex partners during the past year. Another two-level model showed that the club drug users who were female (AOR=1.79, 95% CI=1.03-3.11) and had polydrug use during their lifetime (AOR=1.55, 95% CI=1.01-2.34) had more risk for unprotected sex during the past year than without these characteristics., Conclusion: High-risk sexual behaviours are common among club drug users in China. The prevention and intervention of club drug use could decrease the risk of sexual behaviours which further prevent HIV transmission and other sexually transmitted infections in China., (© 2014 Society for the Study of Addiction.)

Aims: Methamphetamine-related harms in Victoria have increased recently in the context of stable or declining use prevalence. We determine how changes in price and purity of methamphetamine compared to other drugs such as heroin may, in part, explain these divergent patterns., Methods: Detailed methamphetamine and heroin purchase price data from 2152 participant interviews from the Melbourne Injecting Drug User cohort study were used to generate drug price series for the period January 2009-June 2013. Data on drug purity from 8818 seizures made within Victoria were used to generate drug purity series during the same period. Purity-adjusted price data for methamphetamine and heroin were obtained for the period 2009-13 by combining the two data sets., Results: While the average purity of heroin seizures remained consistent and low, the average purity of powder and of crystal methamphetamine seizures increased from 12% [95% confidence interval (CI) = 10-14%] to 37% (95% CI = 20-54%) and 21% (95% CI = 18-23%) to 64% (95% CI = 60-68%), respectively. Crystal methamphetamine purity was bimodal, with observations generally less than 20% or greater than 70%. The average unadjusted price per gram for heroin decreased from $374 (95% CI = $367-381) to $294 (95% CI = $280-308), powder methamphetamine did not change significantly from $252 (95% CI = $233-271), and crystal methamphetamine increased substantially from $464 (95% CI = $416-511) in 2009 to $795 (95% CI = $737-853) in 2011. This increase was offset by an even greater increase in purity, meaning the average purity-adjusted price per gram declined. Furthermore, pure prices of both methamphetamine forms were similar, whereas their unadjusted prices were not. The pure price of heroin fluctuated with no ongoing trends., Conclusions: Decreases in methamphetamine purity-adjusted price along with the bimodality of crystal methamphetamine purity may account for some of the recent increase in methamphetamine-related harm. For a given amount spent, methamphetamine purchase power has increased and the presence of extreme purity variations may challenge individuals' control of consumption., (© 2014 Society for the Study of Addiction.)

Aims: To determine whether violent behaviour increases during periods of methamphetamine use and whether this is due to methamphetamine-induced psychotic symptoms., Design: A fixed-effects (within-subject) analysis of four non-contiguous 1-month observation periods from a longitudinal prospective cohort study., Setting: Sydney and Brisbane, Australia., Participants: A total of 278 participants aged 16 years or older who met DSM-IV criteria for methamphetamine dependence on entry to the study but who did not meet DSM-IV criteria for life-time schizophrenia or mania., Measurements: Violent behaviour was defined as severe hostility in the past month on the Brief Psychiatric Rating Scale (BPRS) (corresponding to assault/damage to property). Days of methamphetamine and other substance use in the past month were assessed using the Opiate Treatment Index. Positive psychotic symptoms in the past month were identified using the BPRS., Findings: There was a dose-related increase in violent behaviour when an individual was using methamphetamine compared with when they were not after adjusting for other substance use and socio-demographics [cf. no use in the past month: 1-15 days of use odds ratio (OR) = 2.8, 95% confidence interval (CI) =1.6-4.9; 16+ days of use OR = 9.5, 95% CI = 4.8-19.1]. The odds of violent behaviour were further increased by psychotic symptoms (OR = 2.0, 95% CI = 1.1-3.6), which accounted for 22-30% of violent behaviour related to methamphetamine use. Heavy alcohol consumption also increased the risk of violent behaviour (OR = 3.1, 95% CI = 1.4-7.0) and accounted for 12-18% of the violence risk related to methamphetamine use., Conclusions: There is a dose-related increase in violent behaviour during periods of methamphetamine use that is largely independent of the violence risk associated with psychotic symptoms., (© 2014 Society for the Study of Addiction.)

Aims: Multiple forms of drug abuse/dependence frequently co-occur with problem/pathological gambling (PPG). The current study examines the extent to which genetic and environmental factors contribute to their co-occurrence., Design: Bivariate models investigated the magnitude and correlation of genetic and environmental contributions to problem/pathological gambling and its co-occurrence with nicotine dependence, cannabis abuse/dependence and stimulant abuse/dependence., Setting: Computer-assisted telephone interviews in the community., Participants: Participants were 7869 male twins in the Vietnam Era Twin Registry, a USA-based national twin registry., Measurements: Life-time DSM-III-R diagnoses for problem/pathological gambling, nicotine dependence, cannabis abuse/dependence and stimulant abuse/dependence were determined using the Diagnostic Interview Schedule., Findings: All drug-use disorders displayed additive genetic and non-shared environmental contributions, with cannabis abuse/dependence also displaying shared environmental contributions. Both genetic [genetic correlation rA  = 0.22; 95% confidence interval (CI) = 0.10-0.34] and non-shared environmental components (environmental correlation rE  = 0.24; 95% CI = 0.10-0.37) contributed to the co-occurrence of problem/pathological gambling and nicotine dependence. This pattern was shared by cannabis abuse/dependence (rA  = 0.32; 95% CI = 0.05-1.0; rE  = 0.36; 95% CI = 0.16-0.55) but not stimulant abuse/dependence (SAD), which showed only genetic contributions to the co-occurrence with problem/pathological gambling (rA  = 0.58; 95% CI = 0.45-0.73)., Conclusions: Strong links between gambling and stimulant-use disorders may relate to the neurochemical properties of stimulants or the illicit nature of using 'hard' drugs such as cocaine. The greater contribution of environmental factors to the co-occurrence between problem/pathological gambling and 'softer' forms of drug abuse/dependence (cannabis, tobacco) suggest that environmental interventions (perhaps relating to availability and legality) may help to diminish the relationship between problem/pathological gambling and tobacco- and cannabis-use disorders., (© 2013 Society for the Study of Addiction.)

Aims: Few studies have examined the statistical association between methamphetamine/amphetamine use and acquisitive crime. Both methamphetamine/amphetamine and cannabis use have been implicated by New Zealand Police as factors in acquisitive offending among active criminal populations. The aim of our study was to examine the statistical association between spending on methamphetamine/amphetamine and cannabis and earnings from acquisitive crime among police detainees in New Zealand., Setting: Four police stations in different regions., Participants: A sample of 2125 police detainees were interviewed about their drug use and acquisitive crime., Design: Statistical models were developed to predict involvement in acquisitive crime using spending on methamphetamine/amphetamine and cannabis for personal use, and to examine associations between the level of spending on methamphetamine/amphetamine and cannabis for personal use and level of dollar earnings from acquisitive crime., Measurements: Self-reported spending on drug use and self-reported earnings from acquisitive crime in the past 30 days., Findings: Spending on cannabis and methamphetamine/amphetamine could predict involvement in acquisitive crime. Level of spending on methamphetamine/amphetamine and cannabis was associated positively with the level of earnings from property crime. Level of spending on methamphetamine/amphetamine was also associated positively with level of earnings from drug dealing. There was a largely negative association between level of spending on cannabis and level of earnings from drug dealing., Conclusions: High spending on methamphetamine/amphetamine is associated statistically with higher earnings from acquisitive crime among police detainees. Further research into this association, and in particular the causal nature of the association, is required to obtain clear policy recommendations., (© 2010 The Authors, Addiction © 2010 Society for the Study of Addiction.)

Aims: To help counter problems related to methamphetamine, Mexico has implemented interventions targeting pseudoephedrine and ephedrine, the precursor chemicals commonly used in the drug's synthesis. This study examines whether the interventions impacted methamphetamine treatment admissions-an indicator of methamphetamine consequences., Design: Quasi-experiment: autoregressive integrated moving average (ARIMA)-based intervention time-series analysis., Interventions: precursor chemical restrictions implemented beginning November 2005; major rogue precursor chemical company closed (including possibly the largest single drug-cash seizure in history) March 2007; precursor chemicals banned from Mexico (North America's first precursor ban) August 2008., Settings: Mexico and Texas (1996-2008)., Measurements: Monthly treatment admissions for methamphetamine (intervention series) and cocaine, heroin and alcohol (quasi-control series)., Findings: The precursor restriction was associated with temporary methamphetamine admissions decreases of 12% in Mexico and 11% in Texas. The company closure was associated with decreases of 56% in Mexico and 48% in Texas; these decreases generally remained to the end of the study period. Neither intervention was associated with significant changes in the Mexico or Texas quasi-control series. The analysis of Mexico's ban was indeterminate due largely to a short post-ban series., Conclusions: This study, one of the first quasi-experimental analyses of an illicit-drug policy in Mexico, indicates that the country's precursor interventions were associated with positive impacts domestically and in one of the Unites States' most populous states--Texas. These interventions, coupled with previous US and Canadian interventions, amount to a new, relatively cohesive level of methamphetamine precursor control across North America's largest nations, raising the possibility that the impacts found here could continue for an extended period., (© 2010 The Authors. Journal compilation © 2010 Society for the Study of Addiction.)

Objectives: Methamphetamine (MA) use among young people is of significant social, economic and public health concern to affected communities and policy makers. While responses have focused upon various perceived severe harms of MA use, effective public health interventions require a strong scientific evidence base., Methods: We conducted a systematic review to identify scientific studies investigating health outcomes associated with MA use among young people aged 10-24 years. The International Classification of Diseases (ICD-10) was used to categorize outcomes and determine the level of evidence for each series of harms., Results: We identified 47 eligible studies for review. Consistent associations were observed between MA use and several mental health outcomes, including depression, suicidal ideation and psychosis. Suicide and overdose appear to be significant sources of morbidity and mortality among young MA users. Evidence for a strong association between MA use and increased risk of human immunodeficiency virus (HIV) and other sexually transmitted infections is equivocal. Finally, we identified only weak evidence of an association between MA use and dental diseases among young people., Conclusions: Available evidence indicates a consistent relationship between MA use and mental health outcomes (e.g. depression, psychosis) and an increased risk of mortality due to suicide and overdose. We found insufficient evidence of an association between MA use and other previously cited harms, including infectious diseases and dental outcomes. As such, future research of higher methodological quality is required to further investigate possible associations. Current interventions should focus attention upon MA-related health outcomes for which sound scientific evidence is available.

Aims: To determine the comparative levels of violent offending and victimization among regular methamphetamine and heroin users., Design: Cross-sectional Setting Sydney, Australia., Participants: A total of 400 regular methamphetamine (METH) and heroin (HER) users (118 methamphetamine users: METH; 161 regular heroin users: HER; 121 regular users of both: BOTH)., Findings: Eighty-two per cent reported a life-time history of committing violent crime, 41% in the past 12 months. There were no group differences in life-time violence, but the METH group were significantly more likely than the HER group to have committed violence in the past 12 months (odds ratio 1.94). Nearly all (95%) reported that they had been a victim of violent crime, 46% in the preceding 12 months, with no group differences. Those who had committed a violent crime in the past 12 months were 13.23 times more likely to have been a victim in that period. The majority believed it unlikely that they would be a victim of (78%), or commit (87%), a violent crime in the next 12 months., Conclusions: Regular methamphetamine use appears to be associated with an increased risk of violent offending, but not victimization, compared with heroin use.

Aim: To investigate the safety and efficacy of once-daily supervised oral administration of sustained-release dexamphetamine in people dependent on methamphetamine., Design: Randomized, double-blind, placebo-controlled trial., Participants: Forty-nine methamphetamine-dependent drug users from Drug and Alcohol Services South Australia (DASSA) clinics., Intervention: Participants were assigned randomly to receive up to 110 mg/day sustained-release dexamphetamine (n = 23) or placebo (n = 26) for a maximum of 12 weeks, with gradual reduction of the study medication over an additional 4 weeks. Medication was taken daily under pharmacist supervision., Measurements: Primary outcome measures included treatment retention, measures of methamphetamine consumption (self-report and hair analysis), degree of methamphetamine dependence and severity of methamphetamine withdrawal. Hair samples were analysed for methamphetamine using liquid chromatography-mass spectrometry., Findings: Treatment retention was significantly different between groups, with those who received dexamphetamine remaining in treatment for an average of 86.3 days compared with 48.6 days for those receiving placebo (P = 0.014). There were significant reductions in self-reported methamphetamine use between baseline and follow-up within each group (P < 0.0001), with a trend to a greater reduction among the dexamphetamine group (P = 0.086). Based on hair analysis, there was a significant decrease in methamphetamine concentration for both groups (P < 0.0001). At follow-up, degree of methamphetamine dependence was significantly lower in the dexamphetamine group (P = 0.042). Dexamphetamine maintenance was not associated with serious adverse events., Conclusions: The results of this preliminary study have demonstrated that a maintenance pharmacotherapy programme of daily sustained-release amphetamine dispensing under pharmacist supervision is both feasible and safe. The increased retention in the dexamphetamine group, together with the general decreases in methamphetamine use, degree of dependence and withdrawal symptom severity, provide preliminary evidence that this may be an efficacious treatment option for methamphetamine dependence.

Aims: To show how the inclusion of agent-based modelling improved the integration of ethno-epidemiological data in a study of psychostimulant use and related harms among young Australians., Methods: Agent-based modelling, ethnographic fieldwork, in-depth interviews and epidemiological surveys., Setting: Melbourne, Perth and Sydney, Australia., Participants: Club drug users in Melbourne, recreational drug users in Perth and street-based injecting drug users in Sydney. Participants were aged 18-30 years and reported monthly or more frequent psychostimulant use., Findings: Agent-based modelling provided a specific focus for structured discussion about integrating ethnographic and epidemiological methods and data. The modelling process was underpinned by collective and incremental design principles, and produced 'SimAmph', a data-driven model of social and environmental agents and the relationships between them. Using SimAmph, we were able to test the probable impact of ecstasy pill-testing on the prevalence of harms--a potentially important tool for policy development. The study also navigated a range of challenges, including the need to manage epistemological differences, changes in the collective design process and modelling focus, the differences between injecting and non-injecting samples and concerns over the dissemination of modelling outcomes., Conclusions: Agent-based modelling was used to integrate ethno-epidemiological data on psychostimulant use, and to test the probable impact of a specific intervention on the prevalence of drug-related harms. It also established a framework for collaboration between research disciplines that emphasizes the synthesis of diverse data types in order to generate new knowledge relevant to the reduction of drug-related harms.

Aim: The aim of the current study was to examine the long-term effect of an early adolescent substance abuse prevention program on trajectories and initiation of amphetamine use into early adulthood., Design: Eight middle schools were assigned randomly to a program or control condition. The randomized controlled trial followed participants through 15 waves of data, from ages 11-28 years. This longitudinal study design includes four separate periods of development from early adolescence to early adulthood., Setting: The intervention took place in middle schools., Participants: A total of 1002 adolescents from one large mid-western US city were the participants in the study., Intervention: The intervention was a multi-component community-based program delivered in early adolescence with a primary emphasis on tobacco, alcohol and marijuana use., Measures: At each wave of data collection participants completed a self-report survey that included questions about life-time amphetamine use., Findings: Compared to a control group, participants in the Midwestern Prevention Project (MPP) intervention condition had reduced growth (slope) in amphetamine use in emerging adulthood, a lower amphetamine use intercept at the commencement of the early adulthood and delayed amphetamine use initiation., Conclusions: The pattern of results suggests that the program worked first to prevent amphetamine use, and then to maintain the preventive effect into adulthood. Study findings suggest that early adolescent substance use prevention programs that focus initially on the 'gateway' drugs have utility for long-term prevention of amphetamine use., (© 2009 The Authors. Journal compilation © 2009 Society for the Study of Addiction.)

Aims: To determine if incarceration was associated with human immunodeficiency virus (HIV) infection and identify risk factors for incarceration among injection drug users (IDUs) participating in an HIV vaccine trial in Bangkok., Design: The AIDSVAX B/E HIV vaccine trial was a randomized, double-blind, placebo-controlled study. A proportional hazards model was used to evaluate demographic characteristics, risk behavior and incarceration as predictors of HIV infection and generalized estimation equation logistic regression analysis to investigate demographic characteristics and risk behaviors for predictors of incarceration., Setting: The trial was conducted in Bangkok Metropolitan Administration drug-treatment clinics, 1999-2003., Participants: A total of 2546 HIV-uninfected IDUs enrolled in the trial., Measurements: HIV testing was performed and an interviewer-administered questionnaire was used to assess risk behavior and incarceration at baseline and every 6 months for a total of 36 months., Findings: HIV incidence was 3.4 per 100 person-years [95% confidence interval (CI), 3.0-3.9] and did not differ among vaccine and placebo recipients. In multivariable analysis, being in jail (P < 0.04), injecting (P < 0.0001), injecting daily (P < 0.0001) and sharing needles (P = 0.02) were associated with HIV infection and methadone maintenance was protective (P = 0.0006). Predictors of incarceration in multivariable analysis included: male sex (P = 0.04), younger age (P < 0.0001), less education (P = 0.001) and being in jail (P < 0.0001) or prison (P < 0.0001) before enrollment., Conclusions: Among IDUs in the AIDSVAX B/E trial, incarceration in jail was associated with incident HIV infection. IDUs in Thailand remain at high risk of HIV infection and additional prevention tools are needed urgently. HIV prevention services, including methadone, should be made available to IDUs.

Aims: Despite good evidence of increased availability and use of amphetamines world-wide, relatively little is known about the epidemiology of young adult amphetamine use; relationships with social functioning, other drug use and mental health at this age; nor of the adolescent predictors of such use. We examined these issues using a representative cohort of young people followed-up in Victoria, Australia., Methods: A stratified, random sample of 1943 adolescents was recruited from secondary schools across Victoria at age 14-15 years. This cohort was interviewed on eight occasions until the age of 24-25 years (78% follow-up at that age). Cross-sectional and predictive associations were assessed using logistic regression., Results: At age 24 years, 12% of the sample had used amphetamines in the past year, with 1-2% using at least weekly. Young adult amphetamine use was predicted strongly by adolescent drug use and was associated robustly with other drug use and dependence in young adulthood. Associations were stronger for more frequent users. Among young adults who had not been using amphetamines at age 20 years, the strongest predictor of use at age 24 years was the use of other drugs, particularly cannabis, at 20 years. Psychological distress did not predict independently an increased likelihood of amphetamine use in this cohort., Conclusion: Young people in Australia using amphetamine at age 24 years are highly likely to be significant polydrug users. The risks for both initiation of young adult amphetamine use, and maintenance of such use, pertain to the heavy use of other drugs. Interventions for heavy amphetamine users at this age are likely to require attention to multiple drug problems.

Aims: To examine the literature pertaining to the cardiovascular effects of methamphetamine and discuss the implications for methamphetamine users., Methods: Relevant literature was identified through comprehensive MEDLINE and EMBASE searches., Findings and Conclusions: There is sufficient clinical and experimental evidence to suggest that methamphetamine can have adverse and potentially fatal effects on the cardiovascular system. The existing literature suggests that: (1) methamphetamine users are at elevated risk of cardiac pathology; (2) risk is not likely to be limited to the duration of their methamphetamine use, because of the chronic pathology associated with methamphetamine use; (3) the risk of cardiac pathology is greatest among chronic methamphetamine users; (4) pre-existing cardiac pathology, due to methamphetamine use or other factors, increases the risk of an acute cardiac event; and (5) methamphetamine use is likely to exacerbate the risk of cardiac pathology from other causes, and may therefore lead to premature mortality.

Objectives: Previous work has highlighted the adverse consequences of early-onset cannabis use. However, little is known about the predictors and effects of early-onset amphetamine use. We set out to examine these issues using a representative cohort of young people followed-up over 11 years in Victoria, Australia., Methods: A stratified, random sample of 1943 adolescents was recruited from secondary schools across Victoria at age 14-15 years. This cohort was interviewed on eight occasions until the age of 24-25 years (78% follow-up at that age). Cross-sectional associations were assessed using logistic regression with allowance for repeated measures. Both proportional hazards models and logistic regression models were used to assess prospective associations., Results: Approximately 7% of the sample had used amphetamines by the age of 17 years. Amphetamine use by this age was associated with poorer mental health and other drug use. The incidence of amphetamine use during the teenage years was predicted by heavier drug use and by mental health problems. By young adulthood (age 24-25 years), adolescent amphetamine users were more likely to meet criteria for dependence upon a range of drugs, to have greater psychological morbidity and to have some limitations in educational attainment. Most of these associations were not sustained after adjustment for early-onset cannabis use., Conclusion: Young people in Australia who begin amphetamine use by age 17 years are at increased risk for a range of mental health, substance use and psychosocial problems in young adulthood. However, these problems are largely accounted for by their even earlier-onset cannabis use.

Aims: To examine the prevalence and correlates of crystal methamphetamine use among young adults in the USA., Design: Cross-sectional analyses of nationally representative data of young adults from the National Longitudinal Study of Adolescent Health (Add Health)., Setting: In-home interviews conducted in 2001-02., Participants: A total of 14,322 respondents aged 18-26 years., Measurements: Past year and 30-day crystal methamphetamine use; crime/violence (ever arrested, past year drug selling, past year violent behavior) and sexual risk behaviors (multiple partners, poor condom use, regretted sex, sex for money)., Findings: Prevalence of past year crystal methamphetamine use was 2.8%; past month was 1.3%. White or Native American race, residence in the west or south, having an ever-incarcerated father, marijuana, cocaine, intravenous drug use and high novelty seeking were associated with greater likelihood of past year use in multivariate analyses. Compared to marijuana and cocaine users, crystal methamphetamine users were more likely to be male, unemployed, reside in the west or south, have an ever-incarcerated father and less likely to be black or Hispanic. Frequent users were no different from occasional users, except being more likely to have dropped out of school. Although crystal methamphetamine use was associated with crime and risky sex, controlling for covariates greatly diminished this relationship., Conclusions: Most users are occasional users, but any past year use is associated with risky and antisocial behaviors, including other illicit drug use. Further research is needed to examine how other drug addiction is associated with methamphetamine use, and to identify longitudinal antecedents for prevention.

Methamphetamine is a substantial public health problem in many communities in the United States and in other parts of the world. In order to bring new knowledge about methamphetamine to policy makers, clinicians and researchers, this volume has compiled a set of articles containing new information about the drug and its effects. The articles contain information presented by researchers at two special methamphetamine meetings sponsored by the National Institute on Drug Abuse in 2005.

Aim: To examine the use of crystal methamphetamine (crystal meth) and its association with high-risk sexual behaviour among gay men in London., Design: Cross-sectional surveys using self-administered questionnaires., Settings: National Health Service (NHS) out-patient human immunodeficiency virus (HIV) treatment clinic in London; NHS HIV testing/sexual health clinics in London; central London gyms., Participants: HIV-positive gay men attending the HIV treatment clinic in 2002-03 (n = 388); HIV-negative gay men attending the HIV testing/sexual health clinics in 2002-03 (n = 266); gay men using the gyms between January and March 2003 (n = 445), 2004 (n = 653) and 2005 (n = 494)., Measurements: Percentage of gay men who reported: (i) using crystal meth in the previous 12 months; (ii) using other recreational drugs (e.g. cocaine, ecstasy, ketamine); (iii) high-risk sexual behaviour in the previous 3 months., Findings: The percentage of gay men who had used crystal meth in the previous year varied by sample (HIV treatment clinic, 12.6%; HIV testing/sexual health clinics, 8.3%; gyms, 19.5%; P < 0.001) but did not change over time in the gyms (19.8%, 20.7%, 17.8%; P = 0.5). In all samples, the majority of men used crystal meth only once or twice a year. Most crystal meth users (> 80%) had taken other recreational drugs. Crystal meth and other drug users were more likely to report high-risk sexual behaviour than other men, e.g. HIV treatment clinic sample: crystal meth users, 34.7%; other drug users, 18.9%, non-users, 10.6%, P < 0.001. Cause and effect could not be established., Conclusion: Among gay men in London surveyed in clinics, approximately one in 10 reported using crystal meth in the previous 12 months (HIV-positive men 12.6%; HIV-negative men 8.3%). Most men used it infrequently--only once or twice a year. There was no evidence of increasing use of crystal meth between 2003 and 2005.

Aims: To examine the prevalence of psychotic symptoms among regular methamphetamine users., Design: Cross-sectional survey., Setting: Participants were recruited from Sydney, Australia, through advertisements in free-press magazines, flyers and through word-of-mouth., Participants: Methamphetamine users (n = 309) who were aged 16 years or over and took the drug at least monthly during the past year., Measurements: A structured face-to-face interview was used to assess drug use, demographics and symptoms of psychosis in the past year. Measures of psychosis included: (a) a psychosis screening instrument derived from the Composite International Diagnostic Interview; and (b) the Brief Psychiatric Rating Scale subscales of suspiciousness, unusual thought content, and hallucinations. Dependence on methamphetamine was measured using the Severity of Dependence Scale., Findings: Thirteen per cent of participants screened positive for psychosis, and 23% had experienced a clinically significant symptom of suspiciousness, unusual thought content or hallucinations in the past year. Dependent methamphetamine users were three times more likely to have experienced psychotic symptoms than their non-dependent counterparts, even after adjusting for history of schizophrenia and other psychotic disorders., Conclusion: The prevalence of psychosis among the current sample of methamphetamine users was 11 times higher than among the general population in Australia. Dependent methamphetamine users are a particularly high-risk group for psychosis.

Aims: To investigate the triggering effects of alcohol, illegal substances and major classes of prescribed psychotropic drugs on criminal violence., Design: A case-crossover design, using each subject as its own control., Setting and Participants: A consecutive sample of 133 violent offenders was recruited from a forensic psychiatric evaluation unit and a national prison evaluation unit in Sweden during 2002-03. Measurements Offenders were assessed with structured interviews. Risk estimates were based on hazard periods of 24 hours. We used standard Mantel-Haenszel methods for statistical analyses., Findings: A 13.2-fold increase of risk of violence [95% confidence interval (CI): 8.2-21.2] was found within 24 hours of alcohol consumption. This increase in violence risk was similar among individuals combining alcohol with benzodiazepines [Relative risk (RR) = 13.2, 95% CI: 4.9-35.3]. Use of benzodiazepines alone in regular doses (RR = 0.4, 95% CI: 0.2-0.5) or antidepressants [selective serotonin reuptake inhibitors (SSRIs) or tricyclics] (RR = 0.4, 95% CI: 0.3-0.8) was associated with a lowered risk for violence., Conclusions: This study confirmed that alcohol is a strong trigger of criminal violence. Benzodiazepines in combination with alcohol caused no further increase of violence risk. Benzodiazepines in regular doses and antidepressants may inhibit violence, but further studies are needed to verify causality. The case-crossover method can contribute to research on the proximal causes of criminal violence.

Aims: The present study extends the findings of a pilot study conducted among regular amphetamine users in Newcastle, NSW, in 1998. It compares key features between current participants in a state capital city (Brisbane) and a regional city (Newcastle) and between the 1998 and current Newcastle sample., Design: Cross-sectional survey. Setting Brisbane and Newcastle, Australia., Participants: The survey was conducted among 214 regular amphetamine users within the context of a randomized controlled trial of brief interventions for amphetamine use., Measurements: Demographic characteristics, past and present alcohol and other drug use and mental health, treatment, amphetamine-related harms and severity of dependence., Findings: The main findings were as follows: (i). the rate of mental health problems was high among regular amphetamine users and these problems commonly emerged after commencement of regular amphetamine use; (ii). there were regional differences in drug use with greater accessibility to a wider range of drugs in a state capital city and greater levels of injecting risk-taking behaviour outside the capital city environment; and (iii). there was a significant increase in level of amphetamine use and percentage of alcohol users, a trend for a higher level of amphetamine dependence and a significant reduction in the percentage of people using heroin and benzodiazepines among the 2002 Newcastle cohort compared to the 1998 cohort., Conclusions: Further longitudinal research is needed to elucidate transitions from one drug type to another and from recreational to injecting and regular use and the relationship between drug use and mental health in prospective studies among users., Implications: Intervention research should evaluate the effectiveness of interventions aimed at: preventing transition to injecting and regular use of amphetamines; toward reducing levels of depression among amphetamine users and interventions among people with severe psychopathology and personality disorders; and toward reducing the prevalence of tobacco dependence among amphetamine users.

Aims: To assess in current injecting heroin and amphetamine users to what extent their history of injecting represents a transition from amphetamine to heroin., Design: Cross-sectional survey., Setting: Sydney, Australia., Participants: One hundred and fifty-one primary heroin injectors and 145 primary amphetamine injectors recruited through advertisements, needle exchanges, methadone maintenance clinics and by word of mouth., Findings: Six major transition patterns were detected: heroin-heroin (n = 61), amphetamines-heroin (n = 60), heroin-amphetamines-heroin (n = 30), amphetamines-amphetamines (n = 80), amphetamines-heroin-amphetamines (n = 41) and heroin-amphetamines (n = 24). A logistic regression analysis predicting presence or absence of a transition from the original primary drug indicated that length of injecting career, years of education and original drug injected were independent predictors. Thus, the longer the injecting career, the greater the likelihood of a transition. If the original drug injected was amphetamine, the greater the likelihood of transition; and the more prior years of education, the lower the chances of a transition., Conclusions: While there was a small preponderance of movement from primary amphetamine injecting to primary heroin injecting, there was also movement in the other direction. Heroin use is not necessarily a stable endpoint for injecting careers.

Aim: To compare the characteristics of heroin, cocaine and amphetamine users having no history of contact with services with those of a group in contact., Method: Multiple agency sampling and field work which included 'snowballing' using 'privileged access interviewers'. Each subject underwent a structured interview which included the Severity of Dependency Scale (SDS), and completed a confidential, self-report questionnaire., Setting: Three contrasting provincial urban locations., Participants: Five hundred and eighty-one regular users of the target drugs. Of these, 380 (65%) denied any contact with police or helping agencies in connection with drug use., Findings: Most zero-contact users (79%) expressed little or no concern about their drug use, and no wish for help or advice. They were much more likely to use stimulants only; less likely ever to inject any drug or, for those that did, to share equipment; less likely to use opioids, amphetamine or cocaine powder on a daily basis; more likely to use Ecstasy; and yielded significantly lower SDS scores for all target drugs save crack. Prevalence of crack use was lower, but the proportion of daily users was the same as in the contact group. Most (69%) contact users remained concerned about their drug use, but 58% expressed little or no confidence that local services could meet their needs. In both groups, SDS scores for cocaine powder were comparable to those for cannabis, LSD and Ecstasy. Of the 495 cannabis smokers identified (85% of the sample), 72% reported daily consumption., Conclusions: The findings are consistent with the hypothesis that 'visible' and 'invisible' drug users are distinct populations in terms of behavioral characteristics, vulnerability to compulsive use, and prevalence of drug-related problems or concern. Purchasers and providers with limited resources should concentrate on improving the range and quality of services for users already in contact rather than attempting to uncover invisible populations. On the basis of SDS scores, cocaine HCI seems to have a relatively modest addictive potential.