Rationale: Low platelet monoamine oxidase (MAO) activity is associated with problem drinking and other deviant behaviors. Since the majority of alcohol abusers are smokers, and tobacco smoke has a direct inhibitory effect on the enzyme, these associations may not be meaningful.
Objective: The authors compared platelet MAO activity and impulsivity in police-referred subjects caught driving while intoxicated and in control subjects, controlling for smoking.
Methods: Platelet MAO activity was measured radioenzymatically and impulsivity scores obtained from questionnaires. Smoking status was self-reported.
Results: Subjects caught driving while intoxicated had significantly higher dysfunctional impulsivity and lower platelet MAO activity than control subjects. This difference in platelet MAO activity between the two groups was significant in non-smokers and ex-smokers.
Conclusions: These findings demonstrate that platelet MAO activity is lower in subjects with socially deviant behavior, and the association of low platelet MAO and problem drinking is not an artifact of smoking.