Hanneke E. Creemers

Intrauterine cannabis exposure leads to more aggressive behavior and attention problems in 18-month-old girls

BACKGROUND The development of the fetal endocannabinoid receptor system may be vulnerable to maternal cannabis use during pregnancy and may produce long-term consequences in children. In this study, we aimed to determine the relationship between gestational cannabis use and childhood attention problems and aggressive behavior. METHODS Using a large general population birth cohort, we examined the associations between parental prenatal cannabis and tobacco use and childhood behavior problems at 18 months measured using the Child Behavior Checklist in N=4077 children. Substance use was measured in early pregnancy. RESULTS Linear regression analyses demonstrated that gestational exposure to cannabis is associated with behavioral problems in early childhood but only in girls and only in the area of increased aggressive behavior (B=2.02; 95% CI: 0.30-3.73; p=0.02) and attention problems (B=1.04; 95% CI: 0.46-1.62; p<0.001). Furthermore, this study showed that long-term (but not short term) tobacco exposure was associated with behavioral problems in girls (B=1.16; 95% CI: 0.20-2.12; p=0.02). There was no association between cannabis use of the father and child behavior problems. CONCLUSIONS Our results suggest that intrauterine exposure to cannabis is associated with an increased risk for aggressive behavior and attention problems as early as 18 months of age in girls, but not boys. Further research is needed to explore the association between prenatal cannabis exposure and child behavior at later ages. Our data support educating future mothers about the risk to their babies should they smoke cannabis during pregnancy.

CHRM2, Parental Monitoring, and Adolescent Externalizing Behavior Evidence for Gene-Environment Interaction

Psychologists, with their long-standing tradition of studying mechanistic processes, can make important contributions to further characterizing the risk associated with genes identified as influencing risk for psychiatric disorders. We report one such effort with respect to CHRM2, which codes for the cholinergic muscarinic 2 receptor and was of interest originally for its association with alcohol dependence. We tested for association between CHRM2 and prospectively measured externalizing behavior in a longitudinal, community-based sample of adolescents, as well as for moderation of this association by parental monitoring. We found evidence for an interaction in which the association between the genotype and externalizing behavior was stronger in environments with lower parental monitoring. There was also suggestion of a crossover effect, in which the genotype associated with the highest levels of externalizing behavior under low parental monitoring had the lowest levels of externalizing behavior at the extreme high end of parental monitoring. The difficulties involved in distinguishing mechanisms of gene-environment interaction are discussed.

DRD2 and DRD4 in relation to regular alcohol and cannabis use among adolescents: does parenting modify the impact of genetic vulnerability? The TRAILS study

AIMS The aims of the present study were to determine the direct effect of DRD2 and DRD4, as well as their interaction with parenting (i.e. rejection, overprotection and emotional warmth), on the development of regular alcohol and cannabis use in 1192 Dutch adolescents from the general population. METHODS Information was obtained by self-report questionnaires. Perceived rejection, overprotection and emotional warmth were assessed at age 10-12. Regular alcohol and cannabis use were determined at age 15-18 and defined as the consumption of alcohol on 10 or more occasions in the past four weeks, and the use of cannabis on 4 or more occasions in the past four weeks. Models were adjusted for age, sex, parental alcohol or cannabis use, and externalizing behavior. RESULTS Carrying the A1 allele of the DRD2 TaqIA polymorphism, or the 7 repeat DRD4, was not directly related to regular alcohol or cannabis use. In addition, adolescent carriers of these genetic risk markers were not more susceptible to the influence of less optimal parenting. Main effects for parenting indicated that overprotection increased the risk of regular alcohol use, whereas the risk of cannabis use was enhanced by parental rejection and buffered by emotional warmth. CONCLUSIONS Our findings do not support an association between DRD2/DRD4 and regular alcohol and cannabis use in adolescents. Given the substance-specific influences of rejection, overprotection and emotional warmth, these parenting factors might be promising candidates for prevention work.

Overlapping Genetic and Environmental Influences on Nonsuicidal Self-injury and Suicidal Ideation: Different Outcomes, Same Etiology?

IMPORTANCE Nonsuicidal self-injury (NSSI) and suicidal self-injury are very harmful behaviors and are associated with several psychiatric disorders. In the recently developed fifth edition of the DSM, NSSI and suicidal behavior disorder are for the first time introduced as conditions in their own right instead of symptoms of other psychiatric disorders. It is unclear to what extent NSSI and suicidal self-injury share the same underlying biological mechanisms and are influenced by the same environmental factors. OBJECTIVE To determine the relative importance of genetic and environmental influences on the variation in NSSI and suicidal ideation and their covariation. DESIGN, SETTING, AND PARTICIPANTS Classical twin design using a sample of 10,678 male and female adult twins (mean [SD] age, 32.76 [6.99] years) from the Australian Twin Registry, a population-based twin registry. Between 1996 and 2009, the twins participated in semistructured telephone interviews that primarily focused on psychiatric disorders. MAIN OUTCOMES AND MEASURES Lifetime presence of self-reported NSSI and suicidal ideation. RESULTS The prevalences of NSSI and suicidal ideation were 4.7% and 26.5%, respectively, and individuals who engaged in self-harm were much more likely to report suicidal ideation (odds ratio = 8.39; 95% CI, 6.84-10.29). Results from a bivariate genetic model indicated that genetic factors explain a substantial part of the variance in both NSSI (37% for men and 59% for women) and suicidal ideation (41% for men and 55% for women), while residual influences (including nonshared environmental influences and measurement error) explain the remainder of the variance. Shared (family) environment did not seem to play a role. Moreover, both behaviors were strongly correlated (r = 0.49 for men and 0.61 for women), and this correlation was largely explained by overlapping genetic influences (76% for men and 62% for women), whereas residual influences accounted for the remainder of the phenotypic correlation. CONCLUSIONS AND RELEVANCE Results indicated that the substantial correlation between NSSI and suicidal ideation is largely driven by overlapping genetic factors, suggesting that the 2 behaviors share similar biological underpinnings. Overlapping residual influences also explain part of the covariance between the 2 traits. Future research should further investigate which genetic and environmental influences underlie the vulnerability to NSSI and suicidal ideation.

Differences between juvenile offenders with and without substance use problems in the prevalence and impact of risk and protective factors for criminal recidivism

BACKGROUND Little is known about the needs of substance-using juveniles in treatment aimed at reducing criminal recidivism. Therefore, we aimed to examine treatment needs of substance-using juvenile offenders. METHODS Differences were examined between juvenile offenders who abstain from substance use (ASU; n=1974) and substance-using juvenile offenders without (SU; n=7000) and with substance use problems (SUP; n=3317), in the prevalence of risk/protective factors for criminal recidivism and strength of associations between risk/protective factors and criminal recidivism. We conducted secondary data analysis on recidivism risk assessments, collected with the Washington State Juvenile Court Assessment, and re-offending data. Analyses of variance and Partial correlations, adjusted for age, gender and ethnicity were applied, as well as Fishers z tests and logistic regression analyses. RESULTS Results showed that substance-using offenders, especially those with substance use problems, had more risk factors and less protective factors than ASU youths in the domains of school, use of free time, relationships, family, attitude, aggression and skills. The associations between most of the risk/protective factors and recidivism were stronger in the ASU group than in the SUP group. Substance use uniquely predicted recidivism, net of risk factors. CONCLUSIONS These results suggest that general interventions for juvenile offenders addressing risk and protective factors with the aim to reduce recidivism may be less effective for offenders with substance use problems, and that substance use (problems) should be addressed, too.

The relationship between cannabis involvement and suicidal thoughts and behaviors

BACKGROUND In the present study, we examined the relationship between cannabis involvement and suicidal ideation (SI), plan and attempt, differentiating the latter into planned and unplanned attempt, taking into account other substance involvement and psychopathology. METHODS We used two community-based twin samples from the Australian Twin Registry, including 9583 individuals (58.5% female, aged between 27 and 40). The Semi-Structured Assessment of the Genetics of Alcoholism (SSAGA) was used to assess cannabis involvement which was categorized into: (0) no cannabis use (reference category); (1) cannabis use only; (2) 1-2 cannabis use disorder symptoms; (3) 3 or more symptoms. Separate multinomial logistic regression analyses were conducted for SI and suicide attempt with or without a plan. Twin analyses examined the genetic overlap between cannabis involvement and SI. RESULTS All levels of cannabis involvement were related to SI, regardless of duration (odds ratios [ORs]=1.28-2.00, p<0.01). Cannabis use and endorsing ≥3 symptoms were associated with unplanned (SANP; ORs=1.95 and 2.51 respectively, p<0.05), but not planned suicide attempts (p>0.10). Associations persisted even after controlling for other psychiatric disorders and substance involvement. Overlapping genetic (rG=0.45) and environmental (rE=0.21) factors were responsible for the covariance between cannabis involvement and SI. CONCLUSIONS Cannabis involvement is associated, albeit modestly, with SI and unplanned suicide attempts. Such attempts are difficult to prevent and their association with cannabis use and cannabis use disorder symptoms requires further study, including in different samples and with additional attention to confounders.

Temperamental Risk Factors for Adolescent Cannabis Use: A Systematic Review of Prospective General Population Studies

In order to establish the evidence for prospective relationships between temperamental and personality indicators of behavioral undercontrol and adolescent cannabis use, we systematically searched relevant papers published through April 2008. We assessed and evaluated 14 studies, of which only 4 were considered of high quality. Using “best evidence” synthesis, we found weak to moderate evidence for prospective relations between a combination of high approach and low avoidance and several measures of cannabis use. The studys limitations are noted. This review provides suggestions and recommendations for future studies in this area.

A genetic perspective on the proposed inclusion of cannabis withdrawal in DSM-5

BACKGROUND Various studies support the inclusion of cannabis withdrawal in the diagnosis of cannabis use disorder (CUD) in the upcoming DSM-5. The aims of the current study were to (1) estimate the prevalence of DSM-5 cannabis withdrawal (criterion B), (2) estimate the role of genetic and environmental influences on individual differences in cannabis withdrawal and (3) determine the extent to which genetic and environmental influences on cannabis withdrawal overlap with those on DSM-IV-defined abuse/dependence. METHOD The sample included 2276 lifetime cannabis-using adult Australian twins. Cannabis withdrawal was defined in accordance with criterion B of the proposed DSM-5 revisions. Cannabis abuse/dependence was defined as endorsing one or more DSM-IV criteria of abuse or three or more dependence criteria. The classical twin model was used to estimate the genetic and environmental influences on variation in cannabis withdrawal, along with its covariation with abuse/dependence. RESULTS Of all the cannabis users, 11.9% met criteria for cannabis withdrawal. Around 50% of between-individual variation in withdrawal could be attributed to additive genetic variation, and the rest of the variation was mostly due to non-shared environmental influences. Importantly, the genetic influences on cannabis withdrawal almost completely (99%) overlapped with those on abuse/dependence. CONCLUSIONS We have shown that cannabis withdrawal symptoms exist among cannabis users, and that cannabis withdrawal is moderately heritable. Genetic influences on cannabis withdrawal are the same as those affecting abuse/dependence. These results add to the wealth of literature that recommends the addition of cannabis withdrawal to the diagnosis of DSM-5 CUD.

Family group conferencing in youth care: characteristics of the decision making model, implementation and effectiveness of the Family Group (FG) plans

BackgroundThe model of Family group-conferencing (FG-c) for decision making in child welfare has rapidly spread over the world during the past decades. Its popularity is likely to be caused by its philosophy, emphasizing participation and autonomy of families, rather than based on positive research outcomes. Conclusive evidence regarding the (cost) effectiveness of FG-c is not yet available. The aim of this protocol is to describe the design of a study to evaluate the (cost) effectiveness of FG-c as compared to Treatment as Usual.Method/DesignThe effectiveness of FG-c will be examined by means of a Randomized Controlled Trial. A multi-informant approach will be used to assess child safety as the primary outcome, and commitment of the social network, perceived control/ empowerment; family functioning and use of professional care as secondary outcomes. Implementation of FG-c, characteristics of family manager and family will be examined as moderators of effectiveness.DiscussionStudying the effectiveness of Fg-c is crucial now the method is being implemented all over the world as a decision making model in child and youth care. Policy makers should be informed whether the ideals of participation in society and the right for self-determination indeed result in more effective care plans, and the money spent on FG-c is warranted.Trial registrationDutch Trial Register number NTR4320. The design of this study is approved by the independent Ethical Committee of the Faculty of Social and Behavioral Sciences of The University of Amsterdam (approval number: 2013-POWL-3308). This study is financially supported by a grant from ZonMw, The Netherlands Organization for Health Research and Development, grant number: 70-72900-98-13158.

The effectiveness of family group conferencing in youth care: A meta-analysis

A meta-analytic study, involving 14 controlled studies (N=88495 participants), was conducted to examine the effectiveness of Family Group Conferencing (FGC) in youth care. Child safety (in terms of reports of child maltreatment and out-of-home placement) and involvement of youth care were included as outcome variables; study, sample and intervention characteristics were included as moderators. Overall, FGC did not significantly reduce child maltreatment, out-of-home placements, and involvement of youth care. Study and sample characteristics moderated the effectiveness of FGC. Retrospective studies found FGC to be more effective than regular care in reducing the recurrence of maltreatment and decreasing the number and length of out-of-home placements, whereas prospective studies found FGC to be not more effective than regular care. Moreover, FGC was found to increase the number and length of out-of-home placements for families with older children and minority groups. The findings of this study showed that robust research proving effectiveness of FGC is limited. It is, therefore, crucial for the safety and protection of children in youth care that, before broadly implementing this decision making model in youth care, more robust studies examining the effectiveness of FGC be conducted.