Cannabis Involvement and Nonsuicidal Self-Injury: A Discordant Twin Approach

The impact of recreational cannabis legalization on youth: the Colorado experience

Over the past two decades, cannabis policies have liberalized in the United States, culminating in the legalization of recreational cannabis in Colorado and Washington state in 2012. This review will focus on the impact of recreational cannabis legalization in Colorado. While the prevalence of past-year and past-month cannabis use has remained relatively steady among adolescents post-legalization, the prevalence of young adult use has continued to rise. Cannabis products with increased potency have become more prevalent and widely used. There are concerns that the use of products with increased potency will increase risk for cannabis use and comorbid mental health disorders, particularly cannabis-induced psychosis and suicidal behavior, although more research is needed to fully understand the impact of high-potency products. Since the legalization of recreational cannabis, numerous additional public health concerns have emerged: unintentional overdoses requiring acute care visits, electronic vaping-associated lung injury, increased motor vehicle collisions related to cannabis consumption, and higher rates of cannabis use during pregnancy. Lessons learned from the first decade of cannabis legalization emphasize the need for research efforts to provide evidence-based guidelines, inform prevention strategies, and implement selective interventions for at-risk populations including youth, individuals with comorbid mental health disorders, and individuals who are pregnant.

Limited psychological and social effects of lifetime cannabis use frequency: Evidence from a 30-year community study of 4,078 twins

BACKGROUND

Cannabis use is associated with outcomes like income, legal problems, and psychopathology. This finding rests largely on correlational research designs, which rely at best on statistical controls for confounding. Here, we control for unmeasured confounders using a longitudinal study of twins.

METHOD

In a sample of 4,078 American adult twins first assessed decades ago, we used cotwin control mixed effects models to evaluate the effect of lifetime average frequency of cannabis consumption measured on substance use, psychiatric, and psychosocial outcomes.

RESULTS

On average, participants had a lifetime cannabis frequency of about one to two times per month, across adolescence and adulthood. As expected, in individual-level analyses, cannabis use was significantly associated with almost all outcomes in the expected directions. However, when comparing each twin to their cotwin, which inherently controls for shared genes and environments, we observed within-pair differences consistent with possible causality in three of the 22 assessed outcomes: cannabis use disorder symptoms (βW-Pooled = .15, SE = .02, p = 1.7 × 10-22), frequency of tobacco use (βW-Pooled = .06, SE = .01, p = 1.2 × 10-5), and illicit drug involvement (βW-Pooled = .06, SE = .02, p = 1.2 × 10-4). Covariate specification curve analyses indicated that within-pair effects on tobacco and illicit drug use, but not cannabis use disorder, attenuated substantially when covarying for lifetime alcohol and tobacco use.

CONCLUSIONS

The cotwin control results suggest that more frequent cannabis use causes small increases in cannabis use disorder symptoms, approximately 1.3 symptoms when going from a once-a-year use to daily use. For other outcomes, our results are more consistent with familial confounding, at least in this community population of twins. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Examining the relationship between non-suicidal self-injury and mental health among female Arab minority students: the role of identity conflict and acculturation stress

Background and objective

Research suggests that individuals from minority backgrounds, including immigrants and ethnic minorities, may be at a higher risk for non-suicidal self-injury (NSSI). The aim of the present research is to examine the relationship between non-suicidal self-injury (NSSI) and identity conflict and acculturation stress, depression, and risk behaviors among female Arab minority students.

Methods

The sample analyzed consisted of 1,529 female Arab students (85.8% B.A. students, 14% M.A. students) aged 21-54 (M = 23, SD = 4.17). The participants completed self-reported questionnaires assessing NSSI engagement, identity conflict and acculturation stress, depression, and risky substance use behavior.

Results

As expected, we found a significant positive association between NSSI and identity crisis. In addition, an identity conflict and acculturation stress impact the effect of depression and risky substance use behaviors in engaging in self-injury. Namely, participants were more likely to engage in NSSI when they also experienced identity conflict and acculturation stress and exhibited depressive symptoms and tended to display risky substance use behavior.

Conclusion

These findings provide evidence that the relationship between depression, risky substance use behavior, and NSSI may be stronger among individuals who experience higher levels of identity conflict and acculturation stress. Implications for intervention and future research are briefly presented.

Cannabis and Intentional Self-injury: a Narrative Review

Purpose of Review

Observational studies assessing the association of cannabis use with subsequent intentional self-injury have reported mixed findings. Longitudinal studies examining the association of cannabis use with subsequent suicide death are notably rare. Our objective was to review longitudinal studies examining cannabis use and subsequent self-harm, suicide attempt, or suicide death.

Recent Findings

Few population-based studies have focused on self-harm with considerable variability across studies in how this outcome has been operationalized. Studies assessing the association between cannabis use and suicide attempt are equivocal in their conclusions and heterogenous in terms of samples utilized and assessment of confounding bias. The results of one meta-analysis were suggestive of dose dependency. For suicide death, the findings are inconsistent, and there is reason for concern of selection bias.

Summary

The existing evidence base on these associations is not yet rigorous enough to allow drawing conclusions on causality. However, cannabis might be seen as an adverse prognostic marker for intentional self-injury.

Variations of cannabis-related adverse mental health and addiction outcomes across adolescence and adulthood: A scoping review

INTRODUCTION

Evidence supporting associations between cannabis use and many health outcomes is growing, however it remains unclear how such associations vary across the lifespan. We therefore aim to answer the following questions: (1) Are the risks of cannabis's adverse effects on mental health and addiction-related outcomes different in adolescents than in adults? (2) What are the relationships between these cannabis's adverse effects and (a) an individual's age at first cannabis use, (b) age at assessment, and (c) duration of cannabis use?

METHODS

We searched Medline, Embase, CINAHL, and PsychINFO from inception to 18 October 2021. Two reviewers independently screened studies and descriptively synthesized results.

RESULTS

We included 140 studies. Cannabis effects on mental health and addiction-related outcomes were worse in adolescents, early cannabis initiators and cannabis users who consumed for longest periods. Evidence of worse long-term adverse effects in adolescents was substantial for psychosis, cannabis, and nicotine use disorders; mixed for depression, suicidality, other substance use and disorders; and limited for anxiety. Additionally, acute cannabis exposure had the opposite trend with adults more often reporting adverse effects than adolescents.

CONCLUSION

The available evidence suggests that cannabis use should be delayed as late as possible in adulthood and shortened in duration across the lifespan to decrease the risk of negative outcomes, while emphasizing the need for adapted harm reduction approaches. This scoping review provides evidence on the role of age and duration of exposure as determinants of cannabis-related adverse effects, which may inform prevention and harm reduction strategies.

SYSTEMATIC REVIEW REGISTRATION

https://doi.org/10.17605/OSF.IO/BYG72.

Dual-harm in adolescence and associated clinical and parenting factors

PURPOSE

Both aggression toward others and self peak in adolescence and interpersonal violence and suicide are among the leading causes of death in young people worldwide. Individuals who show both aggression toward others and self, i.e. dual-harm, may experience the worst outcomes. The current study investigates clinical and parenting factors associated with dual-harming in adolescence, to provide new insights for prevention and treatment.

METHODS

In a prospective cohort of adolescents, oversampled on emotional and behavioral problems (n = 1022; aged 12-17 years), we investigated co-occurrence in harm toward others and self and presented findings in an area-proportional Euler diagram. Four harm groups (no harm, other-harm, self-harm, and dual-harm) were compared on intelligence scores, general functioning, emotional and behavioral problems, substance use, parental hostility, and harsh parenting with ANCOVAs and logistic regressions.

RESULTS

In adolescents that other-harmed, the risk of self-harm was 1.9 times higher than for those who did not harm others. Dual-harm adolescents reported worse overall functioning, more emotional and behavioral problems, more parental hostility and harshness, and were more likely to use substances than those who did not engage in aggressive behaviors. No evidence of differences in intelligence scores between groups were found.

CONCLUSION

These findings highlight a vulnerable group of adolescents, at risk of future suicide, violent offending, and the development of severe psychopathology. Dual-harm is a promising marker for early intervention and referral to specialized mental health professionals. Further research is needed to examine underlying pathways and risk factors associated with persistent dual-harm trajectories into adulthood.

The relationship between alcohol and cannabis use with nonsuicidal self-injury among adolescent inpatients: Examining the 90 days prior to psychiatric hospitalization

BACKGROUND

This study examined the trajectories of alcohol use, cannabis use, suicide planning (SP), and nonsuicidal self-injury (NSSI) prior to hospitalization and examined the role of alcohol and cannabis use, independently and jointly, in predicting NSSI on a daily level and over time.

METHODS

Participants included 71 adolescents hospitalized for suicide risk (75% female; 25% male; M_age = 15.79). All participants drank alcohol at least once in the prior 90-days. We conducted mixed effect models to assess the trajectories of alcohol use, cannabis use, and NSSI over the 90-days prior hospitalization. To test the effect of SP, alcohol use, and cannabis use on NSSI, we conducted logistic random effect models, while controlling for demographics.

RESULTS

SP (OR = 4.47, p < 0.001) and suicide ideation (SI) (OR = 10.09, p < 0.001) significantly increased the odds of engaging in NSSI. Neither cannabis nor alcohol use independently predicted the odds of engaging in NSSI, however, the co-occurrence of alcohol and cannabis use increased the odds of engaging in NSSI on a given day (OR = 30.5, p < 0.05).

CONCLUSIONS

Study findings extend current knowledge about the longitudinal and day-to-day relationships between alcohol and cannabis use and NSSI. Results underscore the importance of developing interventions that address polysubstance use among suicidal adolescents engaging in NSSI.

Cannabinoid use and self-injurious behaviours: A systematic review and meta-analysis

BACKGROUND

The increasing availability of high-potency cannabis-derived compounds and the use of synthetic cannabinoids may be responsible for severe side effects like cognitive impairment, psychosis or self-injurious behaviours (SIB). In particular, SIB like non-suicidal self-injury (NSSI) and deliberate self-harm (DSH) raise growing concern as a possible consequence of cannabis use. However, the research to date has not addressed the relationship between cannabinoid use and SIB systematically.

METHODS

We conducted a systematic review on PubMed up to March 2020, using search terms related to cannabinoids and SIB.

RESULTS

The search yielded a total of 440 abstracts. Of those, 37 studies published between 1995 and 2020 were eligible for inclusion. Cannabinoid use was significantly associated with SIB at the cross-sectional (OR=1.569, 95%CI [1.167-2.108]) and longitudinal (OR=2.569, 95%CI [2.207-3.256]) level. Chronic use, presence of mental disorders, depressive symptoms, emotional dysregulation and impulsive traits might further increase the likelihood of self-harm in cannabis users. Synthetic cannabinoids may trigger highly destructive SIB mainly through the psychotomimetic properties of these compounds.

CONCLUSION

Cannabinoid use was associated with an increased prevalence of self-injury and may act as a causative factor with a duration-dependent manner. Emotional regulation and behavioural impulsivity functions might crucially moderate this association. Future studies should further investigate the mechanisms underlying this association, while exploring potential therapeutic applications of substances modulating the endocannabinoid system.

Cannabis use, depression and self-harm: phenotypic and genetic relationships

BACKGROUND AND AIMS

The use of cannabis has previously been linked to both depression and self-harm; however, the role of genetics in this relationship is unclear. This study aimed to estimate the phenotypic and genetic associations between cannabis use and depression and self-harm.

DESIGN

Cross-sectional data collected through UK Biobank were used to test the phenotypic association between cannabis use, depression and self-harm. UK Biobank genetic data were then combined with consortia genome-wide association study summary statistics to further test the genetic relationships between these traits using LD score regression, polygenic risk scoring and Mendelian randomization methods.

SETTING

United Kingdom, with additional international consortia data.

PARTICIPANTS

A total of 126 291 British adults aged between 40 and 70 years, recruited into UK Biobank.

MEASUREMENTS

Phenotypic outcomes were life-time history of cannabis use (including initial and continued cannabis use), depression (including single-episode and recurrent depression) and self-harm. Genome-wide genetic data were used and assessment centre, batch and the first six principal components were included as key covariates when handling genetic data.

FINDINGS

In UK Biobank, cannabis use is associated with an increased likelihood of depression [odds ratio (OR) = 1.64, 95% confidence interval (CI) = 1.59-1.70] and self-harm (OR = 2.85, 95% CI = 2.69-3.01). The strength of this phenotypic association is stronger when more severe trait definitions of cannabis use and depression are considered. Using consortia genome-wide summary statistics, significant genetic correlations are seen between cannabis use and depression [rg = 0.289, standard error (SE) = 0.036]. Polygenic risk scores for cannabis use and depression explain a small but significant proportion of variance in cannabis use, depression and self-harm within a UK Biobank target sample. However, two-sample Mendelian randomization analyses were not significant.

CONCLUSIONS

Cannabis use appeared to be both phenotypically and genetically associated with depression and self-harm. Limitations in statistical power mean that conclusions could not be made on the direction of causality between these traits.

The Impact of Cannabis Use Disorder on Suicidal and Nonsuicidal Self-Injury in Iraq/Afghanistan-Era Veterans with and without Mental Health Disorders

The objective of this study was to assess the association between cannabis use disorder (CUD) and self-injury among veterans. As expected, after adjusting for sex, age, sexual orientation, combat exposure, traumatic life events, traumatic brain injury, posttraumatic stress disorder, depression, alcohol use disorder, and noncannabis drug use disorder, CUD was significantly associated with both suicidal (OR = 3.10, p = .045) and nonsuicidal (OR = 5.12, p = .009) self-injury. CUD was the only variable significantly associated with self-injury in all three models examined. These findings are consistent with prior research among civilians and suggest that CUD may also increase veterans' risk for self-injurious behavior.