Platelet monoamine oxidase in affective illness and alcoholism.

The authors review the literature on the relationship of platelet monoamine oxidase (MAO) to affective disorders and alcoholism. Although some studies have reported an association between low platelet MAO and bipolar illness, others have failed to replicate this finding. Alcoholism has been related to affective disorders, and it is of note that three studies have found low MAO in alcoholics. Given the physiological consequences of alcoholism, however, the interpretation of these findings is unclear. The authors conclude that nonspecificity of low platelet MAO as a possible correlate of bipolar affective disorder, as well as schizophrenia, increases the burden of proof necessary before findings of low platelet MAO can be accepted as primary.