Juror decision-making concerning defendants with mental health conditions – a systematic review of experimental studies

This systematic review explores the methodological characteristics, features and findings of empirical research adopting an experimental mock juror design to investigate legal decision-making regarding defendants with mental health conditions. A systematic search was conducted using MEDLINE, CINAHL, PsycINFO, PsyArticles and Web of Science, with thirty-two eligible studies included within the final review. Study quality was assessed using the Appraisal Tool for Cross-Sectional Studies (AXIS). All studies were conducted across the United States and Canada, with the exception of one conducted in the United Kingdom. Studies varied significantly in their aims, sampling, variables manipulated and other methodological characteristics. Many effects were reported as non-significant, although a range of significant aggravating and mitigating effects were found in relation to the effect of different diagnostic terms, types of evidence presented and other defendant or participant characteristics on mock jurors’ verdict and sentencing decisions. Inconsistencies in direction of effect were found even amongst the higher quality studies. Strengths, limitations, and recommendations for future research are discussed.