Platelet Monoamine Oxidase B Activity Did Not Predict Destructive Personality Traits or Violent Recidivism: A Prospective Study in Male Forensic Psychiatric Examinees

Abstract

Aims: This prospective study was designed to replicate previous findings of an association between the platelet monoamine oxidase B (MAO-B) activity and factors of relevance for criminal behaviour in a well-documented clinical study population. Methods: Subjects (n = 77, aged 17–76 years, median 30 years) were recruited among consecutive perpetrators of severe interpersonal violent and/or sexual crimes referred to forensic psychiatric investigation. Participants were extensively investigated by structured psychiatric, psychological and social workups, including state-of-the-art rating instruments and official records, and with laboratory tests including venous blood sampling for determination of MAO-B activity. A subset of 36 individuals had lumbar punctures to measure cerebrospinal fluid concentrations of monoamine neurotransmitter metabolites. Results: Platelet MAO-B activity did not show any significant correlation with assessments of childhood behavioural disorders, substance abuse, or psychosocial adversity, nor with any crime-related factors, such as scores on the Life History of Aggression Scale, the Psychopathy Checklist or recidivistic violent crime. No significant correlation was found between MAO-B and any of the monoamine metabolites. Analyses in subgroups of smokers/non-smokers did not change this overall result. Conclusions: The findings of the present study did not support the use of MAO-B as a biological marker for aggression-related personality traits or as a predictor for violent recidivism among violent offenders.

Detention in Juvenile Correctional Facilities Is Associated with Higher Platelet Monoamine Oxidase B Activity in Males

“…Furthermore, MAO-B activity was not associated with any index of different facets of delinquent behavior and psychopathy, with the only exception of verbal aggression evaluated by the OAS-M. This finding is also in accord with previous results showing a lack of association between platelet MAO-B and violent acts (homicide or not), history of suicide attempt, and history of heroin use [ 37 ], or indices of psychosocial adversity or crime-related factors, such as scores on the Life History of Aggression Scale and the Psychopathy Checklist [ 32 ], or with or without criminal recidivism [ 11 ]. It should be stated, however, that other reports documented a correlation of platelet MAO-B activity with criminal behavior in adolescents exposed to early life stress; this correlation disappeared in adolescents living in more favorable conditions, suggesting that this interaction is affected by an improved environment [ 38 , 39 ].…”

“…The lack of significant associations between CD and platelet MAO-B activity confirms and expands previous evidence documenting the lack of associations between this index with symptoms of disruptive behavior symptoms in boys [ 31 ] or with measures of childhood behavioral disorders in forensic psychiatric patients with a history of recidivistic violent crimes [ 32 ].…”

Violent Recidivism: A Long-Time Follow-Up Study of Mentally Disordered Offenders

“…At the subsequent trials, all were found guilty and sentenced: 46 (18–76 years old, median age 30 years) to compulsory forensic psychiatric care and 54 (17–68 years old, median age 32 years) to prison. Baseline data from this study, mainly on neuropsychiatric and biological covariates to violent criminality and aggression, has previously been reported [32], [33], [34], [35], including detailed descriptions of the participants.…”

Novelty, Stress, and Biological Roots in Human Market Behavior

“…Low activities of monoamine oxidase A (MAO-A), an enzyme that degrades amine neurotransmitters (e.g., dopamine, norepinephrine, and serotonin), have been linked to aggressive behavior. In addition, genetic studies have indicated important connections among several genetic variants of this enzyme, environment, and aggression [31,32]. However, the predictive validity of MAO-A for aggression remains uncertain [33].…”