The Influence of Mental Illness Stigma on Juror Decision-Making

The current study examined the influence of a defendant’s mental illness diagnostic labels on mock jurors’ decision-making in a hypothetical criminal case. Due to the present stigmatization of mental illness in the United States, it was hypothesized that if a criminal defendant of a violent crime were given a mental illness diagnosis, specific labels would significantly impact jurors’ perceptions of guilt. Specifically, it was predicted that defendants diagnosed with antisocial personality disorder (ASPD) or borderline personality disorder (BPD) would have more guilty verdicts in comparison to a control. In contrast, those diagnosed with schizophrenia would receive fewer guilty verdicts compared to a control. Participants read a vignette describing a fictional robbery and aggravated assault case, where the defendant was labeled with one of the three diagnoses or had no mental illness description. After reviewing the vignette and jury instructions, participants rendered a verdict. Results revealed no statistically significant correlation between diagnostic labels and verdicts given.