Platelet monoamine oxidase activity as a biological marker in a Swedish forensic psychiatric population

Platelet monoamine oxidase (MAO) activities were determined in 58 non-psychotic males at forensic psychiatric examinations. The aim of the study was to investigate the role of platelet MAO activity as a biological marker in forensic psychiatry, a clinical field with growing need of safe predictors for both treatment outcome and behavior. The study population was heterogeneous with respect to clinical and personality disorders and personality traits. The results confirmed the role of platelet MAO activity as a biological marker for stable personality traits such as impulsiveness, monotony avoidance and aggressiveness. Disorders with high frequencies of these personality traits such as borderline personality disorder and type II alcoholism could secondarily be associated with low levels of platelet MAO activity, whereas no such associations could be found regarding other clinical or personality disorders. Neither psychopathy as assessed by the means of PCL-R nor behavior such as abuse or criminality could be associated with platelet MAO activity. The conclusion is that, due to its close relationship with stable personality traits, platelet MAO activity serves a marker for vulnerability also in forensic psychiatric populations. On the other hand it is not a marker for clinical or personality disorders, or behavior per se.