Assessing psychotic symptoms in forensic evaluations of criminal responsibility – a pilot study using Positive And Negative Syndrome Scale

Description of symptoms and signs related to psychotic disorders at the time of the crime is essential in forensic evaluations of legal insanity. Knowledge of the content of forensic reports is important to improve and secure their quality. Here we report the findings of a pilot study using PANSS as an instrument to assess descriptions of psychotic symptoms in forensic psychiatric reports. Three experienced psychiatrists assessed 20 forensic reports focusing on forensic experts’ descriptions of the defendant’s mental state at the time of the observation and at the time of the alleged crime. PANSS was evaluated as a tool for examining relevant psychotic symptoms, and interrater reliability was calculated. Interrater reliability was satisfactory. It varied based on the percentage of symptoms not described in the reports and on the type of symptom. At both times more symptoms were described from the positive scale of PANSS, than from the negative and the general scale. This pilot study shows that PANSS can be used as an instrument for the structured assessment of psychotic symptoms in written forensic reports and indicates that psychotic symptoms at the time of the alleged crime are poorly described.