Platelet activity and genetics of MAO B: How do they relate to impulsivity and aggression?

Abstract

Low platelet MAO B activity has been shown to be associated with alcoholism as well as impulsivity.So far it is not clear, if polymorphisms of the MAO B gene are related to MAO B levels in platelets and to aspects of alcoholism and impulsivity. So this study investigated, if the intron 13 A/G polymorphism of the MAO B gene is related to MAO B plasma levels and if both biomarkers relate to aspects of alcoholism and impulsivity. Methods: A sample of 60 male abstinent alcoholic patients participated in an experimental Go/NoGo discrimination task as a behavioral measure of impulsivity, filled in questionnaires on aggression and impulsivity, and gave blood samples for genetic analyses and MAO B activity in platelets. Results: Although platelet MAO activity and the genotype were neither associated to each other nor to aspects of alcohol history, both the G allele of the genotype and lower MAO B activity were related to faster reaction times in the behavioral impulsivity paradigm. On questionnaires G allele carriers scored higher on aggression, while A allele carriers were higher on experience seeking. MAO B activity, on the other hand, was associated with impulsivity. So the two biomarkers evidently differentially affect impulsivity and antisocial behavior but may both relate to the component of speed. Conclusions: The MAO B intron 13 A/G polymorphism may not be the most crucial of several genetic polymorphisms for MAO B activity, but does indicate relevance as a behavioral marker.