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Rationale: Comorbid use of heroin and cocaine is highly prevalent among drug users and can greatly increase addiction risk. Nonetheless, little is known regarding how a multi-drug history impacts motivation and cue responsivity to individual drugs., Objective: We used behavioral-economic procedures to examine motivation to maintain drug consumption and tests of drug-seeking to drug-associated cues to assess sensitivity to heroin and cocaine-associated cues in rats that had a self-administration history of heroin, cocaine, or both drugs., Results: Unexpectedly, we found that groups with a polydrug history of heroin and cocaine did not have higher levels of motivation or cue-induced reinstatement of drug-seeking for either cocaine or heroin compared to single drug groups. Nonetheless, we did find drug-specific differences in both economic price and cue sensitivity. Specifically, demand elasticity was lower for cocaine compared to heroin in animals with a single drug history, but not with polydrug groups. In addition, cocaine demand was predictive of the degree of cue-induced reinstatement of drug-seeking for cocaine following extinction, whereas heroin demand was predictive of the degree of reactivity to a heroin-associated cue. Furthermore, although cue reactivity following the initial self-administration phase did not differ across cues and drug history, reactivity to both heroin and cocaine cues was greater during subsequent heroin use compared to cocaine use, and this enhanced reactivity to heroin cues persisted during forced abstinence., Conclusions: These results indicate that there is a greater motivation to maintain cocaine consumption, but higher sensitivity to drug-associated cues with a history of heroin use, suggesting that cocaine and heroin may drive continued drug use through different behavioral processes.

Rationale: Previous studies have shown that rats trained to self-administer heroin and cocaine exhibit opposite preferences, as a function of setting, when tested in a choice paradigm. Rats tested at home prefer heroin to cocaine, whereas rats tested outside the home prefer cocaine to heroin. Here, we investigated whether drug history would influence subsequent drug preference in distinct settings. Based on a theoretical model of drug-setting interaction, we predicted that regardless of drug history rats would prefer heroin at home and cocaine outside the home., Methods: Rats with double-lumen catheters were first trained to self-administer either heroin (25 μg/kg) or cocaine (400 μg/kg) for 12 consecutive sessions. Twenty-six rats were housed in the self-administration chambers (thus, they were tested at home), whereas 30 rats lived in distinct home cages and were transferred to self-administration chambers only for the self-administration session (thus, they were tested outside the home). The rats were then allowed to choose repeatedly between heroin and cocaine within the same session for seven sessions., Results: Regardless of the training drug, the rats tested outside the home preferred cocaine to heroin, whereas the rats tested at home preferred heroin to cocaine. There was no correlation between drug preference and drug intake during the training phase., Conclusion: Drug preferences were powerfully influenced by the setting but, quite surprisingly, not by drug history. This suggests that, under certain conditions, associative learning processes and drug-induced neuroplastic adaptations play a minor role in shaping individual preferences for one drug or the other.

Introduction and Aims: The effect of heroin administration route on speed of transition to regular use is unknown. This paper aims to determine whether the speed of transition from initiation of heroin use to daily heroin use differs by route of administration (injecting, chasing/inhaling or snorting)., Design and Methods: Privileged access interviewer survey of purposively selected sample of 395 current people who use heroin (both in and not in treatment) in London, UK (historical sample from 1991). Data on age and year of initiation, time from initiation to daily use and routes of administration were collected by means of a structured questionnaire. Generalised ordered logistic models were used to test the relationship between route of initial administration of heroin and speed of transition to daily heroin use. Analyses were adjusted for gender, ethnicity, daily use of other drug(s) at time of initiation, year of initiation and treatment status at interview., Results: After adjustment, participants whose initial administration route was injecting had a 4.71 (95% confidence interval 1.34-16.5) increase in likelihood of progressing to daily use within 1-3 weeks of initiation, compared to those whose initial administration route was non-injecting., Discussion and Conclusions: The speed of transition from first use to daily heroin use is faster if the individual injects heroin at initiation of use. Those who initiate heroin use through injecting have a shorter time frame for intervention before drug use escalation. [Hines LA, Lynskey M, Morley KI, Griffiths P, Gossop M, Powis B, Strang J. The relationship between initial route of heroin administration and speed of transition to daily heroin use. Drug Alcohol Rev 2017;00:000-000]., (© 2017 Australasian Professional Society on Alcohol and other Drugs.)

Concurrent use of cocaine and heroin (speedball) has been shown to exert synergistic effects on dopamine neurotransmission in the nucleus accumbens (NAc), as observed by significant increases in extracellular dopamine levels and compensatory elevations in the maximal reuptake rate of dopamine. The present studies were undertaken to determine whether chronic self-administration of cocaine, heroin or a combination of cocaine:heroin led to compensatory changes in the abundance and/or affinity of high- and low-affinity DAT binding sites. Saturation binding of the cocaine analog [(125) I] 3β-(4-iodophenyl)tropan-2β-carboxylic acid methyl ester ([(125) I]RTI-55) in rat NAc membranes resulted in binding curves that were best fit to two-site binding models, allowing calculation of dissociation constant (Kd ) and binding density (Bmax ) values corresponding to high- and low-affinity DAT binding sites. Scatchard analysis of the saturation binding curves clearly demonstrate the presence of high- and low- affinity binding sites in the NAc, with low-affinity sites comprising 85 to 94% of the binding sites. DAT binding analyses revealed that self-administration of cocaine and a cocaine:heroin combination increased the affinity of the low-affinity site for the cocaine congener RTI-55 compared to saline. These results indicate that the alterations observed following chronic speedball self-administration are likely due to the cocaine component alone; thus further studies are necessary to elaborate upon the synergistic effect of cocaine:heroin combinations on the dopamine system in the NAc., (© 2014 Wiley Periodicals, Inc.)

The method of treatment and the results obtained from the treatment of 50 Canadian patients addicted to narcotic drugs who went to England are recorded. These patients were first stabilized on the minimal dose of narcotic drug which permitted them to work, and to acquire security and self-respect. Then, after psychiatric treatment dealing with the basic problem of their personality disorder, complete withdrawal treatment of the narcotic drug was undertaken.Nine of 10 patients aged between 20 and 30, of good social and cultural background, have been relieved of dependence on drugs for over two years.The other 40 patients came from a different background. Nearly all had been imprisoned for drug offences and they had come to England to obtain treatment and to avoid further prison sentences in Canada.The 31 patients whose prison sentences had been directly connected with drug offences are working steadily and leading an apparently normal life.The remaining nine patients had been convicted of criminal acts before becoming addicted to narcotic drugs and, with two exceptions, the results of their treatment compare unfavourably with the other patients, seven having been convicted and imprisoned in London.

Applied the capture-recapture model, through a Poisson regression to a time series of data for admissions to treatment from 1987 to 1996 to estimate the number of heroin addicts in Texas who are "at-risk" for treatment. The entire data set produced estimates that were lower and more plausible than those produced by drawing samples, although these were still sensitive to the assumptions of capture-recapture analysis. (SLD)

Reliability and validity of self-reported behavior within a deviant population are examined using data from 2 interviews with 323 narcotics addicts conducted 10 years apart (1974-75 and 1985-86). Results complement existing reliability and validity studies of alcohol use, and suggest that quality information can be obtained from heroin users. (SLD)

Interviewed 72 heroin-addicted female street prostitutes and assessed fear of Acquired Immune Deficiency Syndrome (AIDS), AIDS risk reduction behavior, and prostitutes' recommendations for AIDS risk reduction programs. Self-reported data showed that, although subjects were afraid of AIDS, irrationality produced by addiction compelled risky behavior. Recommends AIDS-control policies targeted at intravenous drug abusing female prostitutes. (PVV)