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There is substantial evidence for the assumption that particularly heavy cannabis usett is associated with a variety of psychopathologic conditions. Little is known about the relationship between cannabis and anxiety. Prior studies have concluded that cannabis use alone is not sufficient for the development of long-term anxiety, and it has been suggested that cannabis is simply a risk factor that operates in conjunction with other risk factors. One such risk factor may be an individuals' genetic vulnerability. The present study examines the relationship between cannabis use and symptoms of anxiety by taking a developmental molecular-genetic perspective with a focus on a polymorphism involved in the regulation of serotonin. Specifically, we concentrated on changes in cannabis use and symptoms of anxiety over time and differences herein for individuals with and without the short allele of the 5-HTTLPR genotype. Data were from 1424 adolescents over a period of 5 years. We used different statistical analyses to test co-development of cannabis use and symptoms of anxiety throughout adolescence and the possible role of the 5-HTTLPR genotype in this process. Results from different analyses showed that cannabis use is associated with an increase in symptoms of anxiety, but only in carriers of the short allele of the 5-HTTLPR genotype, not in non-carriers. The findings of the present study show first evidence that the links between cannabis use and symptoms of anxiety are conditional on the individuals' genetic make-up. [ABSTRACT FROM AUTHOR]

Aims To determine (1) the prospective associations of conduct problems during early adolescence with tobacco, alcohol and cannabis use in young adulthood and (2) to what extent these associations are due to overlapping genetic versus environmental influences. Design A prospective twin study using biometric twin modelling. Setting Finland. Participants A total of 1847 Finnish twins (943 males and 904 females) were interviewed in early adolescence, 73% of whom ( n = 1353, 640 males and 713 females) were retained in young adulthood. Measurements Symptom counts of conduct disorder (CD) criteria were obtained from a semi-structured clinical interview in early adolescence [age 14-15 years, mean = 14.2, standard deviation (SD) = 0.15]. Frequency of alcohol, tobacco and cannabis use was obtained from a semi-structured clinical interview in young adulthood (age 19.9-26.6 years, mean = 22.4, SD = 0.7). Findings We found modest to moderate phenotypical correlations ( r = 0.16-0.35) between early adolescent CD symptoms and substance use in young adulthood. In males, the phenotypical correlations of CD symptoms with all three substance use variables are explained largely by overlapping genetic influences. In females, overlapping shared environmental influences predominantly explain the phenotypical correlation between CD symptoms and tobacco and cannabis use. Conclusions Conduct disorder symptoms in early adolescence appear to moderately predict substance use in early adulthood. In males, genetic influences seem to be most important in explaining the relationship between conduct disorder symptoms and substance use whereas in females, shared environmental influences seem to be most important. [ABSTRACT FROM AUTHOR]

Aims To examine whether early onset of tobacco or alcohol use, and continued use of tobacco or alcohol in early adolescence, are related to a higher likelihood of developing a cannabis use disorder during adolescence. Design and setting Data were used from four consecutive assessment waves of the TRacking Adolescents' Individual Lives Survey ( TRAILS), a general Dutch population study. TRAILS is an ongoing longitudinal study that will follow the same group of adolescents from the ages of 10 to 24 years. Participants The sample consisted of 1108 (58% female) adolescents (mean ages at the four assessment waves are 11.09, 13.56, 16.27 and 19.05 years, respectively) Measurements Cannabis use disorders were assessed using the Composite International Diagnostic Interview 3.0 ( CIDI). Adolescent tobacco and alcohol use were assessed using self-report questionnaires. Findings Early-onset tobacco use [odds ratio ( OR) = 1.82, confidence interval ( CI) = 1.05-3.14, P < 0.05], but not early-onset alcohol use ( OR = 1.33, CI = 0.84-2.12, P > 0.05), was associated with a higher likelihood of developing a cannabis use disorder. Similarly, adolescents who reported continued use of tobacco ( OR = 2.47, CI = 1.02-5.98, P < 0.05), but not continued use of alcohol ( OR = 1.71, CI = 0.87-3.38, P > 0.05), were more likely to develop a cannabis use disorder. Conclusions Early-onset and continued tobacco use appear to predict the development of a cannabis use disorder in adolescence, whereas early onset and continued alcohol use do not. [ABSTRACT FROM AUTHOR]

Aims To examine the direction of the longitudinal association between vulnerability for psychosis and cannabis use throughout adolescence. Design Cross-lagged path analysis was used to identify the temporal order of vulnerability for psychosis and cannabis use, while controlling for gender, family psychopathology, alcohol use and tobacco use. Setting A large prospective population study of Dutch adolescents [the TRacking Adolescents' Individual Lives Survey ( TRAILS) study]. Participants A total of 2120 adolescents with assessments at (mean) age 13.6, age 16.3 and age 19.1. Measurements Vulnerability for psychosis at the three assessment points was represented by latent factors derived from scores on three scales of the Youth Self- Report and the Adult Self- Report, i.e. thought problems, social problems and attention problems. Participants self-reported on cannabis use during the past year at all three waves. Findings Significant associations ( r = 0.12-0.23) were observed between psychosis vulnerability and cannabis use at all assessments. Also, cannabis use at age 16 predicted psychosis vulnerability at age 19 ( Z = 2.6, P < 0.05). Furthermore, psychosis vulnerability at ages 13 ( Z = 2.0, P < 0.05) and 16 ( Z = 3.0, P < 0.05) predicted cannabis use at, respectively, ages 16 and 19. Conclusions Cannabis use predicts psychosis vulnerability in adolescents and vice versa, which suggests that there is a bidirectional causal association between the two. [ABSTRACT FROM AUTHOR]

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We examined whether externalizing problem behaviors (hyperactivity-impulsivity, aggressiveness, and inattention) predict illicit drug use independently, or whether their associations with drug use are mediated through cigarette smoking. We used a prospective longitudinal design within the FinnTwin12-17 study among Finnish adolescents with baseline at age 12 and follow-up surveys at ages 14 and 17. Path models were conducted with Mplus and included 1992 boys and 2123 girls. The outcome was self-reported ever use of cannabis or other illicit drugs at age 17. The predictors were: externalizing behaviors (hyperactivity-impulsivity, aggressiveness, and inattention) assessed by teachers and parents (age 12) and self-reported cigarette smoking (age 14). The findings differed across behavior studied. The association of hyperactivity-impulsivity with drug use was mostly mediated through earlier cigarette smoking. Concerning aggressiveness and inattention, the results were different among girls than boys. Among girls no significant mediation occurred, whereas among boys more consistent evidence on mediation was seen. Consistently in all models, the direct association of early cigarette smoking on drug use was strong and highly significant. We conclude that the associations of externalizing problem behaviors with illicit drug use are partially mediated through cigarette smoking. Although interventions targeting externalizing problem behaviors may protect adolescents from early onset smoking and subsequently experimenting with drugs, interventions to prevent cigarette smoking initiation are also important in reducing risk of later drug use. [ABSTRACT FROM AUTHOR]

Research on twin-singleton differences in externalizing and internalizing problems in childhood is largely cross-sectional and yields contrasting results. The goal of this study was to compare developmental trajectories of externalizing and internalizing problems in 6- to 12-year-old twins and singletons. Child Behavior Checklist (CBCL) maternal reports of externalizing and internalizing problems were obtained for a sample of 9651 twins from the Netherlands Twin Register and for a representative general population sample of 1351 singletons. Latent growth modeling was applied to estimate growth curves for twins and singletons. Twin-singleton differences in the intercepts and slopes of the growth curves were examined. The developmental trajectories of externalizing problems showed a linear decrease over time, and were not significantly different for twins and singletons. Internalizing problems seem to develop similarly for twins and singletons up to age 9. After this age twins' internalizing symptoms start to decrease in comparison to those of singletons, resulting in less internalizing problems than singletons by the age of 12 years. Our findings confirm the generalizability of twin studies to singleton populations with regard to externalizing problems in middle and late childhood. The generalizability of studies on internalizing problems in early adolescence in twin samples should be addressed with care. Twinship may be a protective factor in the development of internalizing problems during early adolescence. [ABSTRACT FROM AUTHOR]

Aims We examined within a prospective longitudinal study whether cortisol levels were associated with smoking or drinking behaviours, taking parental substance use into account. Design The influence of parental substance use on cortisol levels of their adolescent offspring at age 10–12 years was examined. Next, cortisol levels of adolescents who initiated smoking or drinking at the first data collection (age 10–12) were compared to non-users. Finally, we examined whether cortisol levels could predict new onset and frequency of smoking and drinking 2 years later. Setting and participants First and second assessment data of the TRacking Adolescents' Individual Lives Survey (TRAILS) were used, including 1768 Dutch adolescents aged 10–12 years, who were followed-up across a period of 2 years. Measurements Cortisol was measured in saliva samples at awakening, 30 minutes later, and at 8 p.m. at age 10–12. Self-reported substance use at age 10–12 and 13–14, and parental self-reported substance use were used. Findings Only maternal substance use was related to slightly lower adolescent cortisol levels at 8 p.m. Both maternal and paternal substance use were associated with adolescent smoking and drinking at age 13–14, although fathers' use only predicted the amount used and not the chance of ever use. Finally, higher cortisol levels were related moderately to current smoking and future frequency of smoking, but not to alcohol use. Conclusions In a general population, parental heavy substance use does not seem to affect cortisol levels consistently in their offspring. We found some evidence for higher, instead of lower, hypothalamic–pituitary–adrenal axis activity as a predictor of smoking in early adolescence. [ABSTRACT FROM AUTHOR]

To obtain a better understanding of how genetic and environmental processes are involved in the stability and change in problem behavior from early adolescence into adulthood, studies with genetically informative samples are important. The present study used parent-reported data on internalizing and externalizing problem behavior of adoptees at mean ages 12.4, 15.5 and 26.3. In this adoption study adopted biologically related sibling pairs shared on average 50% of their genes and were brought up in the same family environment, whereas adopted biologically unrelated sibling pairs only shared their family environment. The resemblance between these adopted biologically related (N = 106) and unrelated sibling pairs (N=230) was compared and examined over time. We aimed to investigate (1) to what extent are internalizing and externalizing problem behavior stable from early adolescence into adulthood, and (2) whether the same or different genetic and environmental factors affect these problem behaviors at the 3 assessments. Our results show that both internalizing (rs ranging from .34 to .58) and externalizing behavior (rs ranging from .47 to .69) were rather stable over time. For internalizing and externalizing problem behavior it was found that both genetic and shared environmental influences could be modeled by an underlying common factor, which explained variance in problem behavior from early adolescence into adulthood and accounted for stability over time. The nonshared environmental influences were best modeled by a Cholesky decomposition for internalizing behavior, whereas a time-specific influence of the nonshared environment was included in the final model of externalizing behavior. [ABSTRACT FROM AUTHOR]

Objective: To examine, in a prospective study, whether maternal stress during pregnancy is related to infant temperament.Method: Self-report data on various aspects of prenatal stress were collected from nulliparous women in early pregnancy. Infant temperament was measured at 3 and 8 months by direct observation and by parent report.Results: Complete data were available for 170 term-born infants. Pregnancy-specific anxiety explained 3.3% of the variance of attention regulation at 3 months. Perceived stress and pregnancy anxiety taken together explained 5% of the variance of attention regulation at 8 months. Perceived stress accounted for 8.2% of the variance of difficult behavior of the 3-month-old infant. All results were adjusted for covariates.Conclusions: Increased maternal prenatal stress seems to be associated with temperamental variation of young infants and may be a risk factor for psychopathology later in life. [ABSTRACT FROM AUTHOR]

Background: For many women, pregnancy-related sleep disturbances and pregnancy-related anxiety change as pregnancy progresses and both are associated with lower maternal quality of life and less favorable birth outcomes. Thus, the interplay between these two problems across pregnancy is of interest. In addition, psychological resilience may explain individual differences in this association, as it may promote coping with both sleep disturbances and anxiety, and thereby reduce their mutual effects. Therefore, the aim of the current study was to examine whether sleep quality and sleep duration, and changes in sleep are associated with the level of and changes in anxiety during pregnancy. Furthermore, the study tested the moderating effect of resilience on these associations.Methods: At gestational weeks 14, 24, and 34, 532 pregnant women from the FinnBrain Birth Cohort Study in Finland filled out questionnaires on general sleep quality, sleep duration and pregnancy-related anxiety; resilience was assessed in week 14.Results: Parallel process latent growth curve models showed that shorter initial sleep duration predicted a higher initial level of anxiety, and a higher initial anxiety level predicted a faster shortening of sleep duration. Changes in sleep duration and changes in anxiety over the course of pregnancy were not related. The predicted moderating effect of resilience was not found.Conclusions: The results suggested that pregnant women reporting anxiety problems should also be screened for sleeping problems, and vice versa, because women who experienced one of these pregnancy-related problems were also at risk of experiencing or developing the other problem. [ABSTRACT FROM AUTHOR]

Objective: Youth who report risky substance use and who have a familial history of substance use disorders (SUDs) are at increased risk for developing SUDs themselves later in life. Physiological stress reactivity may be a potential biological mechanism underlying this increased risk. In the current study, we examined (a) whether physiological stress reactivity to a psychosocial stressor was prospectively related to risky substance use later in adolescence and (b) whether this relation was moderated by a familial history of SUDs.Method: Youth from the general population (n = 220) and the children of a parent/parents with an SUD (CPSUDs; n = 60) participated in a psychosocial stress procedure at Time 1. Cortisol and heart rate reactivity were measured during the procedure. Four years later, on average, risky substance use was self-reported (Time 2).Results: Logistic regression analyses showed that youth who had lower cortisol reactivity at Time 1 were more likely to report risky substance use at Time 2. Heart rate reactivity was not related to risky substance use at Time 2, and the relation between stress reactivity and risky substance use was not more pronounced in CPSUDs compared with youth from the general population. These analyses were controlled for alcohol use at Time 1.Conclusions: The present findings suggest hyporeactivity of the hypothalamic-pituitary-adrenal axis in youth who are more likely to engage in risky substance use later in adolescence. These individuals may be inherently hypoaroused, which leads them to seek out substances in order to achieve a more normalized level of arousal. [ABSTRACT FROM AUTHOR]

Abstract: Background: Cannabis is commonly used among pregnant women. It is unclear whether cannabis exposure causes hemodynamic modifications in the fetus, like tobacco does. Aims: This study aims to ascertain fetal blood redistribution due to intrauterine cannabis exposure. Methods: This study was embedded in the Generation R Focus Study, a population-based cohort of parents and children followed from pregnancy onwards. In late pregnancy, fetal hemodynamics was assessed with ultrasound measurements in cannabis-exposed and non-exposed fetuses. Pregnant women reported about substance use during pregnancy. A distinction was made between continued cannabis use (n =9), cannabis use only in early pregnancy (n =14), continued tobacco use (n =85), tobacco use only in early pregnancy (n =92), and no tobacco or cannabis use during pregnancy (n =85). Results: Continued cannabis use was associated with an increased pulsatility and resistance index of the uterine artery, while discontinued cannabis use was associated with a decreased pulsatility, and resistance index, as compared to controls. Additionally, continued cannabis exposure resulted in a significantly higher uterine pulsatility index and uterine resistance index compared to tobacco exposure. Continued cannabis use was found to be associated with a smaller aortic diameter, as well. No association between intrauterine cannabis exposure and the fetal cerebral vascular system was found. Conclusions: Our findings suggest that intrauterine cannabis exposure was associated with changes in hemodynamic programming of the vascular system of the fetus in late pregnancy mainly due to tobacco exposure, but intrauterine cannabis exposure did demonstrate a specific effect on the uterine blood flow. [Copyright &y& Elsevier]

Objective: Increased knowledge about the mechanisms by which some individuals are at risk for early onset of cannabis use might contribute to the improvement of prevention efforts. We focus on the roles of early-adolescent high-intensity pleasure, disruptive behavior, and their interplay in the prediction of onset of cannabis use 2 years later. Method: Data from 81% (n = 1,804) of the participants (51.9% girls) of the Tracking Adolescents' Individual Lives Survey (TRAILS), a prospective general population study in the north of The Netherlands, were analyzed. Measures included parent-reported high-intensity pleasure, and parent and self-reported general disruptive behavior, attention-deficit hyperactivity, oppositional problems, and conduct problems (Child Behavior Checklist/6-18 and Youth Self-Report) at ages 10-12. Onset of cannabis use was assessed at age 12-14 by means of self-reports. Analyses were carried out in Mplus. Results: Early adolescent high-intensity pleasure and disruptive behavior, mainly conduct problems and to some extent attention-deficit hyperactivity, predicted the onset of cannabis use in adolescence. Although we found some mediation by general disruptive behavior, conduct problems, and attention-deficit hyperactivity, the contribution of high-intensity pleasure in predicting the onset of cannabis use was found to be mainly independent from disruptive behavior. Conclusions: The unique contribution of both high-intensity pleasure and disruptive behavior points in the direction of different pathways toward onset of cannabis use. [ABSTRACT FROM AUTHOR]

Abstract: Background: While temperamental characteristics have been related to the onset of cannabis use, it is not clear at what point(s) along the trajectory from early onset of tobacco use (EOT) to early onset of cannabis use (EOC) these characteristics exert their impact. This study examined if (1) temperamental characteristics predispose to EOT that on its turn predisposes to EOC, and (2) temperament moderates the importance of EOT on the progression to EOC. Methods: Data from 1848 (83%) participants in the TRacking Adolescents’ Individual Lives Survey (TRAILS), a prospective population study of Dutch adolescents, were analyzed. We used parent-reports on the Early Adolescent Temperament Questionnaire to assess the dimensions of high-intensity pleasure, frustration, effortful control, shyness and fearfulness at age 10–12. EOT and EOC were defined as use at least once before the ages of 12 and 13 years, respectively, assessed by means of self-reports. We performed mediation and moderation analyses in Mplus. Results: High levels of high-intensity pleasure predisposed to entrance in the trajectory from EOT to EOC. Once tobacco use had been initiated at early age, low levels of shyness and high levels of high-intensity pleasure increased the risk of progression to EOC. Conclusions: Besides a common liability for EOT and EOC based on temperament, the risk of transition from tobacco to cannabis use is modified by temperamental characteristics. Differences in interplay with other risk factors may explain the impact of temperament on distinct points along the substance use trajectory. [Copyright &y& Elsevier]