Claims of amnesia for criminal offenses: psychopathology, substance abuse, and malingering

The forensic psychiatric examiner often encounters defendants who deny memory for their offense. Past research proposes a variety of factors to account for offense amnesia. To date there have been few systematic studies of offense amnesia in relation to psychiatric diagnosis, either alone or in combination with other known factors such as substance use and malingering. We studied 53 pretrial felony defendants who had been referred for psychiatric examination; 40% claimed amnesia for their offense. Examinees with psychotic disorders in general, and schizophrenia in particular, were relatively less likely to claim amnesia than were examinees with other diagnoses. Substance use at the time of the offense and associated substance use disorder diagnoses were positively associated with offense amnesia. Malingering diagnosed by general clinical criteria was a poor predictor of amnesia claims. These data suggests that two prominent reasons for referral for forensic psychiatric evaluation include the presence of psychotic symptoms and claims of amnesia for the offense.