Abstract
The criteria used to judge the success of treatment for mentally ill (psychotic) patients are the same for offenders and non-offenders. For those offender patients detained as psychopaths, the incremental validity of the medical concept is dubious and recourse is often made to the use of the criminal criterion of reconviction in order to measure therapeutic effectiveness. One such study is reported here and others are reviewed. It is argued that reconviction is not a valid measure of psychiatric treatment and that the criteria used to judge therapeutic effectiveness in forensic psychiatry should not differ from those used in all other forms of psychiatric care.