Juror decision making: Does juror stigma, mental health literacy, or the description of a defendant's mental health status, impact decision-making in a mock criminal trial?

Mental health information presented in a trial context was a significant predictor of juror guilt ratings.

• Participants (n = 243) were randomly assigned to one of three conditions varying the amount of mental health information provided.
• The three conditions were: 'control' (mental health explanation could be reasonably inferred but not directly stated), 'symptoms only' (clear mental health symptoms described but no diagnosis), and 'symptoms + diagnosis' (symptoms plus a diagnosis of paranoid schizophrenia).
• Regression analyses identified mental health information as an important predictor of guilt judgements.
• Participants watched a series of videos depicting a fictional criminal trial of an alleged offence of Criminal Damage.

The addition of a diagnosis of paranoid schizophrenia was associated with a reduction in guilt ratings compared to symptoms alone.

• The 'symptoms + diagnosis' condition only differed from the 'symptoms only' condition by additionally describing the condition as 'paranoid schizophrenia'.
• The reduction in guilt ratings associated with the paranoid schizophrenia diagnosis held even after controlling for all other factors including stigma and mental health literacy.
• This was described as 'a particularly notable finding' by the authors.
• This finding has implications for how mental health conditions are described in the courtroom.

Baseline stigma towards mental health conditions was an important predictor of juror guilt judgements.

• Stigma was measured using a standardised scale at baseline.
• Regression analyses identified stigma as one of the important predictors of guilt alongside mental health information and mental health literacy.
• Stigma was included as a covariate in analyses examining the effects of mental health information on guilt ratings.

Mental health literacy (MHL) was an important predictor of guilt, and participants with higher MHL were particularly influenced by increasing mental health information.

• MHL was measured using a standardised scale at baseline.
• Regression analyses identified MHL as an important predictor of guilt.
• Interaction effects indicated that people with higher MHL showed greater decreases in guilt judgements as the amount of mental health information increased.
• The interaction between MHL and mental health information condition was a significant finding in the regression analyses.

The study used an experimental mock trial methodology with random assignment to conditions and video-based stimuli.

• Total sample size was n = 243 participants.
• Participants were randomly assigned to one of three experimental conditions.
• Guilt ratings were measured as the dependent variable.
• Standardised scales were used to measure both stigma towards mental health conditions and mental health literacy (MHL).
• The alleged offence depicted was Criminal Damage.