Abstract

This systematic review explores the bidirectional causal relationship between substance abuse and mental illness, two conditions that frequently co-occur and intensify one another. Substance abuse, involving harmful use of alcohol, drugs, or prescription medications, is strongly associated with mental illnesses such as depres sion, anxiety disorders, schizophrenia, and bipolar disorder. Both conditions share genetic, psychological, and environmental risk factors, and their co-occurrence contributes to disability, poor quality of life, and in creased healthcare and economic costs. Following PRISMA 2021 guidelines, a systematic search of PubMed/ MEDLINE, Scopus, Web of Science, and PsycINFO was conducted to identify peer-reviewed studies exam ining reciprocal effects of substance abuse and mental illness. Eligible studies included empirical research, systematic reviews, and meta-analyses that assessed how substance use influences mental health outcomes and, conversely, how mental illness predisposes individuals to substance misuse. Findings indicate that de pressive symptoms predict subsequent cigarette and e-cigarette use, while cannabis and alcohol use predict later depressive symptoms, particularly during the COVID-19 pandemic. These results highlight the role of societal stressors in amplifying the relationship between substance use and mental health. Evidence suggests that the relationship is neither purely unidirectional nor explained by a single factor but emerges from a convergence of neurobiological changes, executive dysfunction, self-medication tendencies, and broader so cial and cultural influences. The review underscores the importance of integrated treatment approaches that address both substance use and mental illness simultaneously, rather than in isolation. Preventive strategies, early detection, stigma reduction, and community-based interventions are crucial to breaking the cycle of comorbidity. Future research should prioritize longitudinal studies to clarify causality, identify protective factors, and develop evidence-based, culturally sensitive interventions that improve recovery outcomes across diverse populations.

DOI: doi.org/10.63721/25JPIR0119

To Read or Download the Article  PDF