Externalizing behavior problems and cigarette smoking as predictors of cannabis use: the TRAILS Study

Nicotine and Alcohol Use as Predictors of Recreational Cannabis Use in Adolescence: A Systematic Review and Narrative Synthesis

Background: The prevalence of recreational cannabis use among adolescents is a growing public health concern due to its link to short- and long-term adverse effects on adolescents' wellbeing, physical health, mental health, and interpersonal behaviors. Method: Five databases were searched from inception to March 17, 2023, for exposure (nicotine product, alcohol) and outcome (recreational cannabis) in adolescents (persons aged 10-19 years). The studies were screened independently by two reviewers, and the quality of the studies was assessed with Newcastle Ottawa and AXIS tool. PRISMA guidelines were employed in this review. Result: Twenty-one (21) studies involving 2,778,406 adolescents were included in the appraisal and heterogeneity was found among these studies. Ascertainment bias was commonly detected in thirteen (13) of the included studies. Among the substances examined as potential exposures, nicotine-product use emerged as a significant factor associated with future cannabis use among adolescents, particularly in mid-adolescence and in places where recreational cannabis use has been legalized. Conclusion: Current evidence suggests an association between nicotine-product use and subsequent recreational cannabis use among adolescents. However, further research is needed to establish causality between exposure to nicotine substances and the use of recreational cannabis within this age demographic. Additionally, there is a need for the development of prevention programs and targeted policies that continuously inform and update this vulnerable sub-population about the risks associated with cannabis use for leisure.

Developmental pathways of adolescent cannabis use: Risk factors, outcomes and sex-specific differences

BACKGROUND

Characterizing patterns of adolescent cannabis use (CU), as well as risk factors and outcomes uniquely associated with these pathways is essential for informing treatment and prevention efforts. Yet, few studies have examined these issues among youth at-risk of engaging in problematic cannabis use. Further, research accounting for use of other substances or sex differences in patterns of CU remains exceedingly sparse.

METHODS

Trajectory-based modeling was used to identify underlying CU pathways among a predominantly Hispanic (90%) sample of at-risk youth (n = 401; 46% female) across adolescence (ages∼14-18), controlling for baseline substance use and participant demographics. Adolescent psychopathology (i.e., conduct disorder, attention deficit hyperactivity disorder, anxiety, and depression) was examined as a predictor and outcome of CU.

RESULTS

Three trajectories of adolescent CU were identified, with most youth (74%) engaging in relatively "low" levels of use, followed by ∼12% exhibiting an early-initiating "chronic" course, and 14% "escalating" in use. Although boys and girls both experienced increased levels of CU across adolescence, boys were more likely to exhibit escalating and chronic patterns of use. Findings revealed unique associations between adolescent CU pathways and facets of psychopathology; most notably, the relatively robust and bidirectional association between CU trajectories and conduct problem symptoms.

CONCLUSIONS

Specific facets of psychopathology may confer unique associations with CU across development, including the initiation and exacerbation of CU during adolescence.

The interplay between externalizing disorders polygenic risk scores and contextual factors on the development of marijuana use disorders

Externalizing disorders have been extensively linked to substance use problems. However, less is known about whether genetic factors underpinning externalizing disorders and environmental features interact to predict substance use disorders (i.e., marijuana abuse and dependence) among urban African Americans. We examined whether polygenic risk scores (PRS) for conduct disorder (CD) and attention-deficit hyperactivity disorder (ADHD) interacted with contextual factors (i.e., parental monitoring, community disadvantage) to influence risk for marijuana use disorders in a sample of African American youth. Participants (N=1,050; 44.2% male) were initially recruited for an elementary school-based universal prevention trial in a Mid-Atlantic city and followed through age 20. Participants reported on their parental monitoring in sixth grade and whether they were diagnosed with marijuana abuse or dependence at age 20. Blood or saliva samples were genotyped using the Affymetrix 6.0 microarrays. The CD and ADHD PRS were created based on genome-wide association studies conducted by Dick et al. (2010) and Demontis et al. (2017), respectively. Community disadvantage was calculated based on census data when participants were in sixth grade. There was an interaction between the CD PRS and community disadvantage such that a higher CD PRS was associated with greater risk for a marijuana use disorder at higher levels of neighborhood disadvantage. This finding should be interpreted with caution owing to the number of significance tests performed. Implications for etiological models and future research directions are presented.

"Gateway hypothesis" and early drug use: Additional findings from tracking a population-based sample of adolescents to adulthood

To evaluate the consistency of the relationship between early drug use in adolescence and illegal drug use in adulthood as proposed in the "gateway theory" and to determine whether pre-existing depressive symptoms modifies this relationship. We used contractual data from the National Longitudinal Study of Adolescent to Adult health data spanning a 14 year period. We assessed the relationship between gateway drugs at baseline (age 11-20 years) and drug use in adulthood using generalized estimating equation (GEE) regression models. Gateways drugs used in early adolescence were significantly associated with marijuana use, illegal drugs and cocaine in older adolescence, but over time these relationships were not consistent in adulthood. Changes in the pattern of psychoactive drug use were important predictors of drug use in adulthood. A history of higher depressive symptoms was associated with higher frequencies of psychoactive drug use over time. Users of mental health services in adolescence were less likely to use drugs in older adolescence and in adulthood. Relationships between early drug use and later drug use in adulthood cannot be solely explained by the gateway hypothesis. Collectively, adolescent drug prevention and treatment programs should apply theory-based and evidence-proven multisectoral intervention strategies rather than providing a brief counseling on individual's behaviors. This evidence should include understanding that changes in behavior should involve broader analyses of the underlying social context for drug use and in particular the role of the community social norms in driving a group's behaviors.

Correlates of cannabis use among high school students in Shamva District, Zimbabwe: A descriptive cross-sectional study

BACKGROUND

We set out to determine the predisposing, enabling, and reinforcing factors that influence cannabis use in young people aged 13 to 19 years in Shamva District, Zimbabwe.

METHODS

A descriptive cross-sectional study focusing on the correlates of cannabis use was conducted among 311 school-going adolescents who were selected using multistage sampling.

RESULTS

Eight percent of the students in our sample reported current use of cannabis. Associations were found between cannabis use and alcohol consumption (P < 0.001), cigarette smoking (P < 0.001), and having had engaged in sexual intercourse (P < 0.001). Significant relationships were found between recreational use of cannabis and having family members, friends, and parents who have used cannabis (P < 0.001).

CONCLUSIONS

Students who reported using alcohol, smoking cigarettes, and having had engaged in sexual activity were more likely to use cannabis. There is need for identification of these risky behaviours among students, and ecological frameworks and holistic approaches in health promotion programming should be fostered in an effort to increase awareness of the potential harmful effects of cannabis use on adolescents' health and life outcomes.

Multidimensional family therapy decreases the rate of externalising behavioural disorder symptoms in cannabis abusing adolescents: outcomes of the INCANT trial

BACKGROUND

US-based trials have shown that Multidimensional Family Therapy (MDFT) not only reduces substance abuse among adolescents, but also decreases mental and behavioural disorder symptoms, most notably externalising symptoms. In the INCANT trial, MDFT decreased the rate of cannabis dependence among Western European youth. We now focus on other INCANT outcomes, i.e., lessening of co-morbidity symptoms and improvement of family functioning.

METHODS

INCANT was a randomised controlled trial comparing MDFT with individual therapy (IP) at and across sites in Berlin, Brussels, Geneva, The Hague, and Paris. We recruited 450 boys and girls aged 13 up to 18 years with a cannabis use disorder, and their parent(s), and followed them for 12 months. Mental and behavioural characteristics (classified as 'externalising' or 'internalising') and family conflict and cohesion were assessed.

RESULTS

From intake through 12 months, MDFT and IP groups improved on all outcome measures. Models including treatment, site, and referral source showed that MDFT outperformed IP in reducing externalising symptoms.Adolescents were either self-referred to treatment (mostly on the initiative from people close to the teen) or referred under some measure of coercion by an external authority. These two groups reacted equally well to treatment.

CONCLUSIONS

Both MDFT and IP reduced the rate of externalising and internalising symptoms and improved family functioning among adolescents with a cannabis use disorder. MDFT outperformed IP in decreasing the rate of externalising symptoms. Contrary to common beliefs among therapists in parts of Western Europe, the 'coerced' adolescents did at least as well in treatment as the self-referred adolescents.MDFT shows promise as a treatment for both substance use disorders and externalising symptoms.

TRIAL REGISTRATION ISRNCT

ISRCTN51014277.

What clinical differences distinguish depressed teens with and without comorbid externalizing problems?

OBJECTIVE

This study examined differences in co-occurring symptoms, psychosocial correlates, health care utilization and functional impairment in youth who screened positive for depression, stratified by whether or not they also self-reported externalizing problems.

METHODS

The AdoleSCent Health Study examined a random sample of youth ages 13-17 enrolled in a health care system. A total of 2291 youth (60.7% of the eligible sample) completed a brief depression screen: the two-item Patient Health Questionnaire. The current analyses focus on a subset of youth (n=113) who had a follow-up interview and screened positive for possible depression on the Patient Health Questionnaire 9 using a cutoff score of 11 or higher [1]. Youth were categorized as having externalizing behavior if their score was ≥ 7 on the Pediatric Symptom Checklist (PSC) externalizing scale [2,3]. χ(2) tests and Wilcoxon rank sum tests were used to compare groups.

RESULTS

Differences between groups included that youth with depression and externalizing symptoms had a higher rate of obesity and had higher self-reported functional impairment than youth with depression symptoms alone.

CONCLUSIONS

Adding screening for externalizing problems to existing recommendations for depression screening may help primary care providers to identify a high-risk depressed group of youth for referral to mental health services.

Genetic and environmental influences underlying externalizing behaviors, cigarette smoking and illicit drug use across adolescence

We investigated genetic and environmental influences common to adolescent externalizing behavior (at age 12), smoking (at age 14) and initiation of drug use (at age 17) using the FinnTwin12 cohort data. Multivariate Cholesky models were fit to data from 737 monozygotic and 722 dizygotic twin pairs. Heritability of externalizing behavior was 56%, that of smoking initiation/amount 20/32%, and initiation of drug use 27%. In the best-fitting model common environmental influences explained most of the covariance between externalizing behavior and smoking initiation (69%) and amount (77%). Covariance between smoking initiation/amount and drug use was due to additive genetic (42/22%) and common environmental (58/78%) influences. Half of the covariance between externalizing behavior and drug use was due to shared genetic and half due to the environments shared by co-twins. Using a longitudinal, prospective design, our results indicate that early observed externalizing behavior provides significant underlying genetic and environmental influences common to later substance use, here manifested as initiation of drug use in late adolescence.

Patterns of use, sequence of onsets and correlates of tobacco and cannabis

BACKGROUND

While most individuals initiate their use of tobacco prior to onset of cannabis use, recent reports have identified a smaller subset of youth who report onset of cannabis use prior to tobacco use. In this study, we characterize patterns of cannabis and tobacco use (tobacco but not cannabis, cannabis but not tobacco or both) and compare the factors associated with onset of tobacco before cannabis and cannabis before tobacco.

METHODS

Data on 1812 offspring aged 12-32 years, drawn from two related offspring of Vietnam Era twin studies, were used. Individuals were divided into tobacco but not cannabis (T), cannabis but not tobacco (C) and users of both substances (CT). Those who used both could be further classified by the timing of onset of tobacco and cannabis use. Multinomial logistic regression was used to characterize the groups using socio-demographic and psychiatric covariates. Furthermore, data on parental smoking and drug use was used to identify whether certain groups represented greater genetic or environmental vulnerability.

RESULTS

22% (N=398) reported T, 3% (N=55) reported C and 44% reported CT (N=801). Of the 801 CT individuals, 72.8% (N=583), 9.9% (N=77) and 17.3% (N=139) reported onset of tobacco before cannabis, cannabis before tobacco and onsets at the same age. C users were as likely as CT users to report peer drug use and psychopathology, such as conduct problems while CT was associated with increased tobacco use relative to T. Onset of tobacco prior to cannabis, when compared onset of cannabis before tobacco or reporting initiation at the same age was associated with greater cigarettes smoked per day, however no distinct factors distinguished the group with onset of cannabis before tobacco from those with initiation at the same age.

CONCLUSION

A small subset of individuals report cannabis without tobacco use. Of those who use both cannabis and tobacco, a small group report cannabis use prior to tobacco use. Follow-up analyses that chart the trajectories of these individuals will be required to delineate their course of substance involvement.

Externalizing behaviors and cigarette smoking as predictors for use of illicit drugs: a longitudinal study among Finnish adolescent twins

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.