In the Netherlands, in approximately 30% of the more serious criminal cases, a pretrial forensic mental health report (FMHR) is requested to inform the court whether a mental disorder was present at the time of alleged crime, whether this disorder affected behavior and decision-making at the time of the offense and how this disorder may affect future (criminal) behavior. While informative for sentencing decisions, information about mental disorders or risk is irrelevant for the question whether the defendant committed the alleged crime. Yet based on cognitive psychological theory of evidence evaluation and integration, we hypothesized that information in an FMHR would affect the evaluation of evidence as well as the ultimate decision about guilt. Using an experimental vignette study among 200 law and criminology students with manipulation of the presence and content of an FMHR, we found a main effect of the presence of an FMHR report on decisions about guilt. The proportion of guilty verdicts increased with almost 20% when an FMHR was present compared to when this report was absent, irrespective of the type of disorder (schizophrenia or personality disorder) or level of recidivism risk (low or high) present in the report. We did not find support for our hypothesis that this effect could be explained by assimilation of other available evidence. Implications for further research and practice are discussed.

In contrast to jurisdictions with bifurcated criminal justice proceedings, in Belgium and the Netherlands a defendant’s assessed risk of recidivism is known to triers of fact prior to making decisions about guilt. In three experiments conducted in those two countries, we investigated whether information about recidivism risk would bias the fact finders’ evaluations of evidence and the defendant’s credibility, and their final decision on guilt. Specifically, student participants (Belgian sample: N = 368; Dutch sample: N = 236) and jury-eligible Belgian participants (N = 75) read a vignette about an aggravated assault with circumstantial evidence and a defendant who denied committing the alleged offense. Participants were randomly assigned to one of three vignettes: one without risk information, one describing a low risk of recidivism, and one describing a high risk of recidivism. We found no direct or indirect effect of risk on the proportion of guilty verdicts or on the evaluation of the evidence. We did find that participants who read that the defendant was low risk evaluated the innocence claim as being more credible, compared to those who were given high-risk information or no risk information. Moreover, higher credibility ratings were associated with a higher likelihood of a not-guilty verdict. While preliminary, these findings suggest recidivism risk information may influence fact finding, and merit replication, especially with judges.