Prevalence of comorbid substance use in major depressive disorder in community and clinical settings, 1990-2019: Systematic review and meta-analysis

Background: Comorbidity between Substance Use Disorders (SUDs) and major depression is highly prevalent. This systematic review and meta-analysis aimed to estimate the prevalence of SUDs in subjects diagnosed with a major depressive disorder (MDD) in community, inpatient and outpatient settings. Methods: A comprehensive literature search of Medline, EMBASE, PsycINFO and CINAHL databases was conducted from 1990 to 2019. Prevalence of co-morbid SUDs and MDD were extracted and odds ratios (ORs) were calculated using random effects meta-analysis. Results: There were 48 articles identified by electronic searches with a total sample size of 348,550 subjects that yielded 14 unique epidemiological studies, 2 national case registry studies, 7 large cohort studies and 20 clinical studies using in- or out-patients. The prevalence of any SUD in individuals with MDD was 0.250. Maximum prevalence was found with alcohol use disorder (0.208), followed by illicit drug use disorder (0.118) and cannabis use disorder (0.117). Meta-analysis showed the pooled variance of any AUD in men with MDD was 36%, which was significantly higher than that for females with MDD (19%, OR 2.628 95% CI 2.502, 2.760). Conclusions: Few studies were published over the last decade so current prevalence rates of SUD in MDD are needed. Meta-analysis revealed that SUDs in MDD are highly prevalent and rates have not changed over time. The persistently high prevalence suggests there is an urgent need for more informative studies to help develop better prevention and treatment options for reducing prevalence of SUDs in persons with major depression and co-morbid disorders.