Prevalence of comorbid substance use disorders with anxiety disorders or post-traumatic stress disorder in people seeking treatment for substance abuse: a systematic review protocol.

OBJECTIVE: This systematic review will aim to assess evidence of the prevalence of comorbid substance use disorders with anxiety disorders or post-traumatic stress disorder in people seeking treatment for substance use. INTRODUCTION: Research shows that anxiety disorders and post-traumatic stress disorder are highly prevalent in people with substance use disorders and can worsen the treatment outcomes, increasing the risk of relapse and poor adherence. However, evidence from systematic reviews on the prevalence of these comorbidities in substance use treatment settings is limited. INCLUSION CRITERIA: Participants will be people seeking treatment for substance use. Studies will be included if they have investigated the prevalence of the comorbid substance use disorders with anxiety disorders or post-traumatic stress disorder in treatment settings. METHODS: Primary studies will be screened from the databases MEDLINE, PsycINFO, CINAHL, and Embase, and from searches to source gray literature. Eligible cross-sectional and cohort studies published after 1994 with no language limits will be retrieved, and their methodological quality will be assessed. Data extraction will include study details, methods, and outcomes. Results will be described by narrative summary or, if studies are sufficiently similar, a meta-analysis will be performed. Prevalence data will be pooled for meta-analysis by a random effects model. The results will be presented graphically in a forest plot. Data heterogeneity will be statistically tested using χ2 and I2 tests. If substantial heterogeneity is detected, sources of heterogeneity will be explored by subgroup analysis and meta-regression, and results will be presented by a narrative summary. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42020149956.