Psychopathy and biological markers in a forensic psychiatric population

Abstract: The aim of this investigation was to determine the frequency of psychopathy and examine the co-morbidity pattern in a forensic psychiatric population in Sweden. In addition, possible biological markers were evaluated. The research subjects were 61 non-psychotic men, admitted for forensic psychiatric investigations in Uppsala during 1992 - 1994.Psychopathy, as assessed with the Psychopathy-Checklist-Revised (PCL-R), was common, and 25 % of the subjects had a high degree of psychopathy. Strong co-morbidity was found between psychopathy and Axis I and Axis II DSM-III-R disorders, particularly abuse/dependence disorders and borderline personality disorders. Psychopathy- and aggression-related personality traits, as measured with the Karolinska Scales of Personality (KSP), were significantly correlated with Hare's psychopathy traits. The KSP personality traits were stable over time and between situations, as shown by follow-up after two years.Low platelet MAO activity was found in subjects with disorders characterized by a high degree of psychopathy, defined by means of the KSP. However, there was no relationship with criminal behavior.Although clinically euthyroid, the research subjects had elevated serum levels of triiodothyronine compared to those in healthy men. Higher levels of triiodothyronine were found in subjects with conditions characterized by abuse and asocial and violent behavior.Serum levels of total testosterone, free testosterone and sex hormone-binding globulin were higher in subjects who had been given a diagnosis of type II alcoholism, antisocial personality disorder and/or antisocial behavioral traits of the PCL-R. Moreover, multiple regression analysis showed a relationship between free testosterone and the psychopathy-related scales of the KSP also when age and signs of hepatic damage were taken into account.