Moral wrongfulness and insanity: a New Zealand sample

Introduction: This study sought to identify the common characteristics amongst defendants found legally insane, compared to those who were psychiatrically evaluated yet convicted of their crime. Method: A retrospective review of court-ordered psychiatric court reports and legal outcomes was conducted, for all defendants referred for insanity evaluations in the largest city in New Zealand (and its surrounding rural regions) for a 7-year period. Results: The majority (60%; 37) of those referred for evaluation were found legally insane. The opinion regarding moral wrongfulness was the single factor that differentiated successful insanity defendants from those who were found guilty. Conclusions: Despite the centrality of the insanity defence to forensic psychiatry, few studies internationally consider characteristics of those found insane, particularly in comparison with those who are found guilty. Psychiatrically evaluated defendants in this sample were relatively homogenous, perhaps due to the court liaison nurse screening process.