Unraveling the Association Between Schizophrenia and Substance Use Disorder-Predictors, Mechanisms and Treatment Modifications: A Systematic Review

Abstract

Individuals with schizophrenia are particularly vulnerable to substance abuse problems. Comorbidity with substance use disorders (SUDs) frequently results in early death and increased dysfunction observed in schizophrenia. This dual diagnosis can be explained through multiple general mechanisms. Tobacco, alcohol, cannabis, and cocaine are substances widely used by individuals with schizophrenia. This study highlights the predictors, mechanisms responsible for the relationship between substance use disorder and schizophrenia and how it can help with the treatment of both disorders. The publications were rigorously reviewed after being found in multiple databases. The study's inclusion criteria were research published within the last five years, publications written in English, full-text availability, and human studies. A total of ten papers were selected for examination from a total of 9,106 articles found using the search method across several databases. This study follows the rules listed within the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist 2009. The information gathered from these published studies was used to investigate the elements that contribute to the link between schizophrenia and substance abuse. Here, we evaluate a close relationship between schizophrenia and substance use disorders. The articles studied exhibit a bidirectional association between the two disorders in most individuals. From our analysis, the comorbidity between the two disorders is partially due to shared polygenic liability. Individuals with schizophrenia have dysfunctional Mesocorticolimbic brain reward circuits indicating a history of substance use. An underlying genetic vulnerability to schizophrenia may be triggered by extensive cannabis usage at a young age. A combination of psychological and pharmacological interventions for both disorders can significantly improve the outcome.

The impact of lifetime substance use on psychiatric comorbidities and treatment seeking in patients with alcohol use disorders

“…Hence, data regarding benzodiazepines should be treated with particular caution in this case. We also found a relationship between cannabis use and the occurrence of disorders from the F20–F29 group, which is well-documented in the literature 6 , 7 , 21 , 22 . The literature also provides data on the relationship between COC use and the occurrence of disorders from the F20–F29 group 22 .…”

Mortality in people with schizophrenia: a systematic review and meta‐analysis of relative risk and aggravating or attenuating factors

“…Additionally, comorbid substance use, and cannabis use in particular, can worsen adherence to antipsychotics [182][183][184] . All these factors point to the need to screen for and address substance use disorders as early as possible when treating patients with schizophrenia 185,186 .…”

Self-Entropic Broadening Theory: Toward a New Understanding of Self and Behavior Change Informed by Psychedelics and Psychosis

“…The case of Syd Barrett, the frontman of Pink Floyd who purportedly left the band due to the development of schizophrenia precipitated by excessive LSD use, may further illustrate this potential relationship between chronic LSD exposure and psychosis (Fusar-Poli, 2007). However, it is worth mentioning these cases were likely confounded by use of cannabis, which is a well-known risk factor for development of schizophrenia (Masroor et al, 2021), and has also been shown to alter dopaminergic signaling in the striatum (Sami et al, 2015), including the associative striatum (see Sami et al, 2015, for a review) which is widely implicated in psychosis (Conn et al, 2020). Further complicating the picture, first generation antipsychotics, with significant antidopaminergic action, were tried in three of the four cases of LSD-induced psychosis and found to be ineffective (Glass and Bowers, 1970).…”