Background: The purpose of this systematic review was to examine the association and directionality between mental health disorders and substance use among adolescents and young adults in the U.S. and Canada. Methods: The following databases were used: Medline, PubMed, Embase, PsycINFO, and Cochrane Library. Meta-analysis used odds ratios as the pooled measure of effect. Results: A total of 3656 studies were screened and 36 were selected. Pooled results showed a positive association between depression and use of alcohol (odds ratio (OR) = 1.50, 95% confidence interval (CI): 1.24–1.83), cannabis (OR = 1.29, 95% CI: 1.10–1.51), and tobacco (OR = 1.65, 95% CI: 1.43–1.92). Significant associations were also found between anxiety and use of alcohol (OR = 1.54, 95% CI: 1.19–2.00), cannabis (OR = 1.36, 95% CI: 1.02–1.81), and tobacco (OR = 2.21, 95% CI: 1.54–3.17). A bidirectional relationship was observed with tobacco use at baseline leading to depression at follow-up (OR = 1.87, CI = 1.23–2.85) and depression at baseline leading to tobacco use at follow-up (OR = 1.22, CI = 1.09–1.37). A unidirectional relationship was also observed with cannabis use leading to depression (OR = 1.33, CI = 1.19–1.49). Conclusion: This study offers insights into the association and directionality between mental health disorders and substance use among adolescents and young adults. Our findings can help guide key stakeholders in making recommendations for interventions, policy and programming.

Catatonia is a rare but life-threatening condition characterized by a constellation of psychomotor disturbances. The most widely used treatments of catatonia include benzodiazepines and electroconvulsive therapy. Despite the widespread use of benzodiazepines and the high response rate of catatonia to ECT, there are instances where catatonia does not respond to first-line treatments. This study aimed to evaluate the efficacy of repetitive transcranial magnetic stimulation (rTMS) in managing catatonia. A systematic literature search was conducted on the following databases: Medline, PubMed, Cochrane Library, Embase, PsycINFO and ClinicalTrials.gov for registered but not yet published studies. Out of 244 initially identified articles, there remained eight case reports and 1 case series eligible after screening. Of the twelve total cases, nine showed clinical improvement. However, there was significant heterogeneity in the complexity of the clinical situation, the severity of clinical features of catatonia, underlying causes, and rTMS treatment protocols between studies. The results of this study are inconclusive. However, rTMS might be trialed for the management of catatonia when first-line treatment options fail, are unavailable, or need to be used with caution. Our review incorporating the most up to date evidence highlights the need for more extensive, standardized, randomized clinical trials to investigate the efficacy of rTMS for treating catatonia.