Cannabis use and episodic memory performance among adolescents: Moderating effects of depression symptoms and sex.

OBJECTIVE: Cannabis use has been linked to poorer episodic memory. However, little is known about whether depression and sex may interact as potential moderators of this association, particularly among adolescents. The current study addresses this by examining interactions between depression symptoms and sex on the association between cannabis use and episodic memory in a large sample of adolescents. METHOD: Cross-sectional data from 360 adolescents (M age = 17.38, SD = .75) were analyzed at the final assessment wave of a two-year longitudinal study. We used the Drug Use History Questionnaire to assess for lifetime cannabis use, and the Computerized Diagnostic Interview Schedule for Children, Fourth edition to assess the number of depression symptoms in the past year. Subtests from the Wechsler Memory Scale, Fourth Edition and the California Verbal Learning Test, Second Edition were used to assess episodic memory performance. RESULTS: The effect of the three-way interaction among cannabis use, depression symptoms, and sex did not have a significant impact on episodic memory performance. However, follow-up analyses revealed a significant effect of the two-way interaction of cannabis use and depression symptoms on episodic memory, such that associations between cannabis use and episodic memory were only significant at lower and average levels of depression symptoms. CONCLUSIONS: Contrary to our hypotheses, we found that as depression symptoms increased, the negative association between cannabis use and episodic memory diminished. Given the use of a predominantly subsyndromic sample, future studies should attempt to replicate findings among individuals with more severe depression.

Genetic versus environmental influences on callous-unemotional traits in preadolescence: The role of parenting and parental psychopathology.

Children with callous-unemotional (CU) traits are at risk for severe conduct problems. While CU traits are moderately heritable, parenting also predicts risk. However, few studies have investigated whether parenting factors (e.g., acceptance, conflict, parental psychopathology) moderate the etiology of CU traits, while accounting for gene-environment correlations. To address this knowledge gap, we used data from 772 twin pairs from the Adolescent Brain and Cognitive Development Study to test bivariate models that explored overlapping etiological influences on CU traits and child reports of their parenting environment. We also used gene-by-environment interaction models to test whether parenting moderated genetic versus environmental influences. There were no overlapping etiological influences on CU traits and parental acceptance, but modest genetic and non-shared environmental overlap between CU traits and family conflict. Parental acceptance and psychopathology moderated non-shared environmental influences, with stronger non-shared environmental influences on CU traits among children who experienced lower parental acceptance and greater parental psychopathology. Family conflict only moderated environmental influences when models did not covary for conduct problems. Parental acceptance and parental psychopathology may be specific environmental protective and risk factors for CU traits, whereas family conflict may represent a general environmental risk factor for both CU traits and conduct problems.

Evidence Lacking for Cannabis Users Slacking: A Longitudinal Analysis of Escalating Cannabis Use and Motivation among Adolescents.

OBJECTIVE: Reduced motivation is often noted as a consequence of cannabis use. However, previous work has yielded mixed results and focused largely on adults. To address these limitations, this study examined longitudinal associations between cannabis use and self-reported motivation in a large adolescent sample. METHOD: Participants were 401 adolescents aged 14-17 at baseline who completed five bi-annual assessments. We assessed motivation at three timepoints using two self-report questionnaires: the Apathy Evaluation Scale and the Motivation and Engagement Scale (disengagement, persistence, planning, self-efficacy, and valuing school subscales). Controlling for relevant covariates, we used latent growth curve modeling to characterize patterns of cannabis use and motivation over time, examining bidirectional influences between these processes. RESULTS: On average, adolescent cannabis use frequency increased significantly over time. The disengagement and planning facets of motivation also increased significantly over time, whereas other aspects of motivation remained stable. At baseline, greater cannabis use was associated with greater disengagement, lower planning, and lower valuing of school. Greater baseline cannabis use also predicted lesser increases in disengagement over time. After controlling for the effect of sex, age, depression, and use of alcohol and nicotine, only the baseline association between cannabis use and valuing school remained significant. CONCLUSIONS: Our results do not support a prospective link between cannabis use and reduced motivation among adolescents. Although most observed associations were accounted for by covariates, greater cannabis use was cross-sectionally associated with lower perceived value of school, which may contribute to poorer educational and later life outcomes.

Exercise, Decision-Making, and Cannabis-Related Outcomes among Adolescents.

OBJECTIVE: Poor decision-making may represent a risk factor for adverse cannabis-related outcomes, whereas exercise has been linked to better executive functioning and substance use outcomes. This study examines the associations between self-reported exercise and cannabis use (CU) outcomes over 6 months among adolescents, and whether these are mediated by exercise-related effects on decision-making. Method: Participants were 387 adolescents aged 15-18 who completed two assessments 6 months apart. Self-reported past 6-month hours/week of exercise were assessed at baseline. At the 6-month follow-up, participants completed measures assessing past 6-month CU frequency, presence of CU disorder (CUD), and CU-related problems, as well as risky decision-making tasks (Iowa Gambling Task, Game of Dice Task, Cups Task), which were used to derive a latent construct of decision-making. We used prospective mediation to examine the role of decision-making in the relationship between exercise and CU outcomes. Results: More self-reported exercise at baseline predicted greater CU frequency at the 6-month follow-up, but did not predict the presence of a CUD, or cannabis-related problems. After controlling for confounds, baseline exercise did not predict better decision-making at follow-up. Decision-making did not predict CU outcomes, and indirect effects of decision-making were not significant. Conclusions: Contrary to hypotheses, adolescents reporting more exercise at baseline also reported higher CU frequency in our sample. This association may be explained by factors like sample characteristics or sports types, but more research is needed to explore this. Results did not support a mediating role for decision-making in the associations between exercise and CU outcomes.Supplemental data for this article can be accessed online at https://doi.org/10.1080/10826084.2021.1906279.

Adverse Effects of Cannabis Use on Neurocognitive Functioning: A Systematic Review of Meta- Analytic Studies.

Objective: As the perceived risk of cannabis use continues to decline among youths and access continues to increase, it has become more important to synthesize the rapidly growing literature on the effects of cannabis on neurocognition. Hundreds of studies examining associations between cannabis use and neurocognitive functioning have been published in recent decades. However, results often differ across individual studies, particularly when sample sizes are small. Meta-analytic methods help to make sense of this literature and have been increasingly applied to studies on cannabis use and neurocognition. Methods: A systematic literature search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted to identify peer-reviewed meta-analyses of neurocognitive or functional neuroimaging data that examined associations between cannabis use and non-acute effects on neurocognitive functioning (n = 8). Results: Current findings suggest that regular healthy cannabis users, regardless of age, display poorer neurocognitive functioning relative to nonusers of small to medium effect sizes across many neurocognitive domains, as well as functional brain alterations when compared to non-users. Adverse effects are not uniform across neurocognitive domains and evidence for adolescent-onset users having poorer neurocognitive outcomes remains equivocal based on these studies. However, less is known about cannabis effects on neurocognition among clinical samples, as findings from specific clinical samples revealed mixed results. Conclusions: Meta-analyses have played an important role in helping to grasp the totality of results from a large body of literature on cannabis effects on neurocognition, yet more research (particularly large-scale longitudinal studies) is needed to identify critical periods or patterns of use that are more likely to result in negative outcomes.

Decision-Making as a Latent Construct and its Measurement Invariance in a Large Sample of Adolescent Cannabis Users.

OBJECTIVE: Relative to the vast literature that employs measures of decision-making (DM), rigorous examination of their psychometric properties is sparse. This study aimed to determine whether three measures of DM assess the same construct, and to measure invariance of this construct across relevant covariates. METHOD: Participants were 372 adolescents at risk of escalation in cannabis use. DM was assessed via four indices from the Cups Task, Game of Dice Task (GDT), and Iowa Gambling Task (IGT). We used confirmatory factor analysis to assess unidimensionality of the DM construct, and moderated nonlinear factor analysis (MNLFA) to examine its measurement invariance. RESULTS: The unidimensional model of DM demonstrated good fit. MNLFA results revealed that sex influenced mean DM scores, such that boys had lower risk-taking behaviors. There was evidence of differential item functioning (DIF), such that IQ and age moderated the IGT intercept and GDT factor loading, respectively. Significant effects were retained in the final model, which produced participant-specific DM factor scores. These scores showed moderate stability over time. CONCLUSIONS: Indices from three DM tasks loaded significantly onto a single factor, suggesting that these DM tasks assess a single underlying construct. We suggest that this construct represents the ability to make optimal choices that maximize rewards in the presence of risk. Our final DM factor accounts for DIF caused by covariates, making it comparable across adolescents with different characteristics. (JINS, 2019, 25, 661-667).

Is Cannabis Use Associated with Various Indices of Motivation among Adolescents?

Decreased motivation is often noted as a consequence of cannabis use (CU). Previous work has yielded mixed findings, relied mostly on adult samples, and varied to the extent that it accounted for potential confounds. This study examines associations between CU and several motivation indices among adolescents. We hypothesized that regular cannabis users would report lower motivation than light users, and that greater lifetime and past 30-day CU amounts would be associated with decreased motivation. Participants were 79 adolescents, ages 14-18, classified as recent regular cannabis users (n = 36) or light users (n = 43). Frequency and amount of substance use were assessed across participants' lifetime and during the past 30 days. Motivation was measured through the Apathy Evaluation Scale and Motivation and Engagement Scale. To examine associations between CU and our motivation indices, we conducted a series of two-step hierarchical multiple regressions. Variables found to correlate with any motivation measure were entered on step 1 (e.g., mental health, other substance use) and the relevant CU variable was entered on step 2. After controlling for confounds, no significant differences were observed between regular and light users on any motivation index, p > .01. Similarly, no associations between motivation and lifetime or past 30-day CU amount were observed, p > .01. Our findings do not support a link between reduced motivation and CU among adolescents after controlling for relevant confounds. Future studies will examine the levels of CU which influence motivation in adolescents, and the conditions under which this link becomes manifest.

Does Cannabis Use Cause Declines in Neuropsychological Functioning? A Review of Longitudinal Studies.

Cannabis use has been linked to impairments in neuropsychological functioning across a large and continually expanding body of research. Yet insight into underlying causal relations remains limited due to the historically cross-sectional nature of studies in this area. Recently, however, studies have begun to use more informative design strategies to delineate these associations. The aim of this article is to provide a critical evaluation and review of research that uses longitudinal designs to examine the link between cannabis use and neuropsychological functioning. In summarizing the primary findings across these studies, this review suggests that cannabis use leads to neuropsychological decline. However, across most studies, these associations were modest, were present only for the group with the heaviest cannabis use, and were often attenuated (or no longer significant) after controlling for potential confounding variables. Future studies with neuropsychological data before and after initiation of cannabis use, along with careful measurement and control of "shared risk factors" between cannabis use and poorer neuropsychological outcomes, are needed to better understand who, and under what conditions, is most vulnerable to cannabis-associated neuropsychological decline. (JINS, 2017, 23, 893-902).

Decision-Making Does not Moderate the Association between Cannabis Use and Body Mass Index among Adolescent Cannabis Users.

OBJECTIVES: Results from research conducted on the association between cannabis use and body mass index (BMI) reveal mixed findings. It is possible that individual differences in decision-making (DM) abilities may influence these associations. METHODS: This study analyzed how amount of cannabis use, DM performance, and the interaction of these variables influenced BMI and clinical classifications of weight among adolescents (ages 14 to 18 years; 56% male; 77% Hispanic). The sample consisted primarily of cannabis users (n=238) without a history of significant developmental disorders, birth complications, neurological conditions, or history of mood, thought, or attention deficit/hyperactivity disorder at screening. Furthermore, few participants engaged frequently in other drug use (except for alcohol and nicotine). RESULTS: Analyses revealed that more lifetime cannabis use was associated with a higher BMI and greater likelihood of being overweight/obese. Interactions between DM and cannabis use on BMI were not significant, and DM was not directly associated with BMI. DISCUSSION: Our findings suggest that among adolescents, cannabis use is associated with a greater BMI regardless of DM abilities and this association is not accounted for by other potential factors, including depression, alcohol use, nicotine use, race, ethnicity, or IQ. (JINS, 2016, 22, 944-949).

Advances in urea cycle neuroimaging: Proceedings from the 4th International Symposium on urea cycle disorders, Barcelona, Spain, September 2013.

Our previous imaging research performed as part of a Urea Cycle Rare Disorders Consortium (UCRDC) grant, has identified specific biomarkers of neurologic injury in ornithine transcarbamylase deficiency, OTCD. While characterization of mutations can be achieved in most cases, this information does not necessarily predict the severity of the underlying neurological syndrome. The biochemical consequences of any mutation may be modified additionally by a large number of factors, including contributions of other enzymes and transport systems that mediate flux through the urea cycle, diet and other environmental factors. These factors likely vary from one patient to another, and they give rise to heterogeneity of clinical severity. Affected cognitive domains include non-verbal learning, fine motor processing, reaction time, visual memory, attention, and executive function. Deficits in these capacities may be seen in symptomatic patients, as well as asymptomatic carriers with normal IQ and correlate with variances in brain structure and function in these patients. Using neuroimaging we can identify biomarkers that reflect the downstream impact of UCDs on cognition. This manuscript is a summary of the presentation from the 4th International Consortium on urea cycle disorders held in, Barcelona, Spain, September 2, 2014.

Investigating neurological deficits in carriers and affected patients with ornithine transcarbamylase deficiency.

BACKGROUND: Urea cycle disorders are caused by dysfunction in any of the six enzymes and two transport proteins involved in urea biosynthesis. Our study focuses on ornithine transcarbamylase deficiency (OTCD), an X-linked disorder that results in a dysfunctional mitochondrial enzyme, which prevents the synthesis of citrulline from carbamoyl phosphate and ornithine. This enzyme deficiency can lead to hyperammonemic episodes and severe cerebral edema. The objective of this study was to use a cognitive battery to expose the cognitive deficits in asymptomatic carriers of OTCD. MATERIALS AND METHODS: In total, 81 participants were recruited as part of a larger urea cycle disorder imaging consortium study. There were 25 symptomatic participants (18 female, 7 male, 25.6 year s ± 12.72 years), 20 asymptomatic participants (20 female, 0 male, 37.6 years ± 15.19 years), and 36 healthy control participants (21 female, 15 male, 29.8 years ± 13.39 years). All participants gave informed consent to participate and were then given neurocognitive batteries with standard scores and T scores recorded. RESULTS: When stratified by symptomatic participant, asymptomatic carrier, and control, the results showed significant differences in measures of executive function (e.g. CTMT and Stroop) and motor ability (Purdue Assembly) between all groups tested. Simple attention, academic measures, language and non-verbal motor abilities showed no significant differences between asymptomatic carriers and control participants, however, there were significant differences between symptomatic and control participant performance in these measures. CONCLUSIONS: In our study, asymptomatic carriers of OTCD showed no significant differences in cognitive function compared to control participants until they were cognitively challenged with fine motor tasks, measures of executive function, and measures of cognitive flexibility. This suggests that cognitive dysfunction is best measurable in asymptomatic carriers after they are cognitively challenged.

The urea cycle disorders.

The urea cycle is the primary nitrogen-disposal pathway in humans. It requires the coordinated function of six enzymes and two mitochondrial transporters to catalyze the conversion of a molecule of ammonia, the α-nitrogen of aspartate, and bicarbonate into urea. Whereas ammonia is toxic, urea is relatively inert, soluble in water, and readily excreted by the kidney in the urine. Accumulation of ammonia and other toxic intermediates of the cycle lead to predominantly neurologic sequelae. The disorders may present at any age from the neonatal period to adulthood, with the more severely affected patients presenting earlier in life. Patients are at risk for metabolic decompensation throughout life, often triggered by illness, fasting, surgery and postoperative states, peripartum, stress, and increased exogenous protein load. Here the authors address neurologic presentations of ornithine transcarbamylase deficiency in detail, the most common of the urea cycle disorders, neuropathology, neurophysiology, and our studies in neuroimaging. Special attention to late-onset presentations is given.

Motives for Cannabis Use and Risky Decision Making Influence Cannabis Use Trajectories in Teens.

The current study will examine the interactive effects of motives for cannabis use (i.e., health or recreational) and risky decision making (DM) on cannabis use trajectories among adolescents. Data from 171 adolescents, aged 14-17 at the initial visit (baseline), were prospectively analyzed across five time points approximately six months apart. Latent growth curve modeling and linear regression analyses were used. We found a significant interactive effect of "recreational motives" and risky DM on the rate of cannabis use over time. Specifically, among those less likely to use cannabis for recreational purposes, riskier DM was associated with a faster increase in the rate of use over time relative to those with lower risky DM. Additionally, a significant main effect showed that those with a greater proclivity to use cannabis for health purposes had higher initial levels of use at baseline and faster increases in the rate of use over time. Regardless of risky DM, using cannabis for health purposes is associated with faster increases in cannabis use escalation. Additionally, risky DM does impact the association between recreational motives for use and cannabis use trajectories. Future work should examine these associations with additional motives for cannabis use that have been previously validated within the literature.

An exploratory follow-up study of cannabis use and decision-making under various risk conditions within adolescence.

OBJECTIVE: Studies examining the associations between decision-making (DM) and cannabis use (CU) often use cross-sectional, adult samples, and composite scores or single tasks to assess DM. The present study explored differential associations between tasks assessing DM under various risk conditions (i.e., ambiguous vs. explicit; gain vs. loss) and CU frequency, CU-related problems, and CU disorder (CUD) onset across a 2-year period within adolescence. METHOD: Adolescents (n = 401, 90% Hispanic) aged 14-17 at baseline participated in five biannual assessments. CU frequency, CU-related problems, and CUD were assessed using the Drug Use History Questionnaire, Marijuana Problems Scale, and Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, fourth edition, respectively. DM was assessed using the Iowa gambling task (IGT), Game of Dice Task (GDT), and Cups Task. We used latent growth curve modeling to examine bidirectional associations between DM and escalation in CU frequency and CU-related problems, and discrete time survival analyses to determine whether baseline performance across DM tasks predicted CUD onset. RESULTS: Baseline performance on the GDT predicted greater escalation in CU (ß = .200, p = .008) and CU-related problems (ß = .388, p = .035). No other significant associations were found. CONCLUSIONS: DM under explicit risk may be a more salient risk factor for escalating CU and CU-related problems than DM under ambiguous risk. Deficits in executive functioning could partially explain the results. Findings suggest that neurocognitive development should inform prevention and intervention efforts focused on reducing CU. Given the exploratory nature of the present study, replication of findings is needed. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Risky decision-making as an antecedent or consequence of adolescent cannabis use: findings from a 2-year longitudinal study.

BACKGROUND AND AIMS: Although poor decision-making (DM) has been correlated with problematic cannabis use (CU), cross-sectional designs make it difficult to determine whether poor DM represents an antecedent and/or consequence of CU. The current study measured bidirectional associations between CU and DM among adolescents over 2 years and compared these findings to those observed with episodic memory, which is consistently reported as a consequence of CU. We also measured the role of DM as a risk factor for cannabis use disorder (CUD) onset. DESIGN: Two-year longitudinal study with five bi-annual assessments. PARTICIPANTS: Participants were 401 adolescents aged 14-17 years at baseline. SETTING: Miami, Florida, USA. MEASUREMENTS: CU frequency and CUDs were assessed at each time-point through the Drug Use History Questionnaire and Structured Clinical Interview for DSM-IV, respectively. Neurocognition was assessed at odd time-points throughout the Iowa Gambling Task, Game of Dice Task and Cups Task [decision-making (DM)] and the Wechsler Memory Scale IV and California Verbal Learning Test II (episodic memory). We used latent growth curve modeling to examine bidirectional influences between CU and neurocognition over time. We applied discrete time survival analyses to determine whether baseline DM predicted CUD onset. FINDINGS: Greater lifetime CU frequency was associated with poorer episodic memory at baseline (bs = -14.84, -16.44, Ps = 0.038, 0.021). Greater CU escalation predicted lesser gains in immediate episodic memory (b = -0.05, P = 0.020). Baseline DM did not predict CU escalation (b = 0.07, P = 0.421), nor did escalation in CU predict changes in DM (b = 0.02, P = 0.352). Baseline DM also did not predict CUD onset (adjusted OR = 1.01, 95% confidence interval = 0.98-1.06). CONCLUSIONS: This study replicates findings that poorer episodic memory in adolescents appears to be a consequence of cannabis use, even among adolescents at earlier stages of use. Poor decision-making does not appear to be either a consequence of or a risk factor for escalating cannabis use or onset of cannabis use disorder among adolescents.

Sex differences in bidirectional associations between conduct problems and cannabis use across two years of adolescence.

BACKGROUND: There is a large body of research that has identified bidirectional associations between conduct problems and cannabis use. Despite growing knowledge regarding comorbidities between conduct problems and cannabis use, it remains unclear whether these findings generalize across both males and females. The current study examined sex differences in longitudinal associations between conduct problems and cannabis use in a predominantly Hispanic sample of adolescents followed over a two-year period. METHODS: Participants were 401 adolescents (89.8% Hispanic, 46% female; Mage = 15.5) taking part in a two-year longitudinal investigation examining the associations between neurocognitive functioning and cannabis use. The sample consisted predominantly of youth selected for risk of cannabis escalation, with 90% reporting using cannabis, nicotine, or alcohol prior to baseline. Negative binomial cross-lagged regressions and simple slope difference tests were used for all analyses. RESULTS: We found support for bidirectional associations between conduct problems and cannabis use, controlling for demographics, covariates, and baseline frequencies. Simple slope difference tests revealed that there was a significant, positive association between baseline cannabis use and subsequent conduct problems among females but not males. In contrast, the association between baseline conduct problems and subsequent frequency of cannabis use did not differ as a function of sex. CONCLUSIONS: Our results underscore the importance of viewing cannabis use as a risk factor for maladjustment rather than solely as a consequence, particularly among female adolescents. Information gained from temporal sequencing of cannabis use and conduct problem symptoms can guide the selection of intervention programs for referred youth.

Neural response to monetary loss among youth with disruptive behavior disorders and callous-unemotional traits in the ABCD study.

Etiological models highlight reduced punishment sensitivity as a core risk factor for disruptive behavior disorders (DBD) and callous-unemotional (CU) traits. The current study examined neural sensitivity to the anticipation and receipt of loss, one key aspect of punishment sensitivity, among youth with DBD, comparing those with and without CU traits. Data were obtained from the Adolescent Brain and Cognitive Development (ABCD)SM Study (N = 11,874; Mage = 9.51; 48% female). Loss-related fMRI activity during the monetary incentive delay task was examined across 16 empirically-derived a priori brain regions (e.g., striatum, amygdala, insula, anterior cingulate cortex, medial prefrontal cortex) and compared across the following groups: (1) typically developing (n = 693); (2) DBD (n = 995), subdivided into those (3) with CU traits (DBD + CU, n = 198), and (4) without CU traits (DBD-only, n = 276). Latent variable modeling was also employed to examine network-level activity. There were no significant between-group differences in brain activity to loss anticipation or receipt. Null findings were confirmed with and without covariates, using alternative grouping approaches, and in dimensional models. Network-level analyses also demonstrated comparable activity across groups during loss anticipation and receipt. Findings suggest that differences in punishment sensitivity among youth with DBD are unrelated to loss anticipation or receipt. More precise characterizations of other aspects punishment sensitivity are needed to understand risk for DBD and CU traits.

Adolescent Cannabis Use and Conduct Problems: The Mediating Influence of Callous-Unemotional Traits.

Cannabis use has been linked to an increased risk of engaging in conduct problem behaviors. However, little existing research has considered intervening processes and shared risk factors that may contribute to this association. The current investigation examines whether callous-unemotional traits, which have shown associations with adolescent cannabis use and conduct problem development, may exhibit a mediating influence on this relationship. Using a longitudinal cohort of youth (n = 390) at increased risk for escalating in their use of cannabis, we found that baseline cannabis use (age~15) was associated with higher levels of trait-like conduct problems (ages~16 & 17), even after controlling for important autoregressive and cross-lagged effects, along with a number of other shared risk factors (e.g., co-occuring substance use, age, sex). Findings also revealed that callous-unemotional traits partially mediated this relationship, with the hypothesized model accounting for approximately one-third of the variance in the conduct problem outcome (R2=.34). These results indicate that callous-unemotional traits may play an important intermediary role in the association between cannabis use and the development of problem behaviors.

Bidirectional Longitudinal Associations Between Cannabis Use and Body Mass Index Among Adolescents.

Introduction: Literature on the association between cannabis use and body mass index (BMI) among adults suggests that greater cannabis use is associated with a lower BMI. However, results are mixed among adolescents, with both cross-sectional and longitudinal studies finding positive, negative, and nonsignificant associations between cannabis use and BMI. This longitudinal study aims to shed light on these associations by prospectively examining the associations between cannabis use and BMI across a 2-year window in a large sample of adolescent cannabis users. Methods: Participants were 401 adolescents ages 14-17 at baseline who were at risk for escalation in their use of cannabis. We conducted a parallel process latent growth curve model to examine associations between the cannabis use intercept, BMI intercept, cannabis use slope, and BMI slope. Results: Results showed that baseline BMI predicted a positive and significant association with cannabis use slope. In addition, there was a significant and negative correlation between the cannabis use slope and the BMI slope. These significant associations remained after controlling for relevant covariates. Conclusions: Results are consistent with the adult literature that reports a negative association between cannabis use and BMI. Future research should focus on uncovering the mechanisms that may drive the association between cannabis use and BMI.

Effects of Adolescent Cannabis Use on Motivation and Depression: A Systematic Review.

PURPOSE OF REVIEW: This article reviews recent behavioral and neuroimaging studies to elucidate whether adolescent cannabis use is related to reduced motivation and increased risk of depression. RECENT FINDINGS: Recent work suggests that heavy adolescent cannabis use predicts poorer educational outcomes, often presumed to reflect reduced academic motivation, as well as increased levels of depressive symptoms. However, evidence of a link between cannabis use and general motivation was lacking. Factors such as concurrent alcohol and tobacco use, trajectories of cannabis use during adolescence, and cannabis-related changes in underlying neurocircuitry may impact associations among cannabis use, motivation, and depression. SUMMARY: Heavy adolescent cannabis use is associated with poorer educational outcomes and increased levels of depressive symptoms. The role of depression in how cannabis may affect motivation, broadly, is not yet clear, as most studies have not examined associations among all three constructs. Future work should explore possible overlap between cannabis effects on motivation and depression, and clarify the temporality of these associations.