The psychological subtype of intimate partner violence and its effect on mental health: protocol for a systematic review and meta-analysis

Background/aim Psychological violence is estimated to be the most common form of intimate partner violence (IPV). Despite this, research on the independent effect of psychological violence on mental health is scarce. Moreover, the lack of a clear and consistent definition of psychological violence has made results difficult to compare. The present study therefore aims to consolidate knowledge on psychological violence by conducting a systematic review and random-effects meta-analysis on the association between psychological violence and mental health problems, when controlling for other types of violence (e.g. physical and sexual) and taking into account severity, frequency, and duration of psychological violence. Method The present study is registered in the International Prospective Register for Systematic Reviews (PROSPERO; #CRD42018116026) and the study design follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA; Additional file 1). A dual search will be conducted in the electronic databases PsycINFO, PubMed, EMBASE, and Web of Science. Data will be extracted using Endnote and Covidence and a meta-analysis will be conducted using Metafor-package in the programming language R. The Quality Assessment Tool for Quantitative Studies developed by the Effective Public Health Practice Project will be used to assess the quality of the included studies (i.e. weak, moderate and strong). Results and discussion The present review will help consolidate knowledge on psychological violence by evaluating whether frequency, severity or actual "type" of psychological violence produces the most harm. A thorough quality assessment will help overcome potential limitations regarding expected variations in terminology and assessment of psychological violence. Systematic review registration PROSPERO .