Moclobemide response in depressed patients: Association study with a functional polymorphism in the monoamine oxidase-A promoter

Monoamine oxidase A (MAOA) is one of the key enzymes in the metabolism of monoaminergic neurotransmitters which supposedly play an important role in the etiology of affective disorders. Moreover, MAO-A inhibitors such as moclobemide are effective in the pharmacotherapy of depressive syndromes. Recently, a novel functional repeat polymorphism in the promoter of the MAO-A gene has been reported, with the longer alleles [3a, 4, 5] being more active than the shorter one[3] (Deckert et al., 1999). We tried to identify whether these polymorphisms are involved in the pharmaco-response to moclobemide. 64 patients (15 males, 49 females) were included in the study. DSM-IV diagnosis of major depression was achieved on the basis of a structured interview (SCID). Mean age was 51.89 years and mean age of onset 41.07 years. Response was measured weekly with the following instruments: HAMD, CGI, GAS, SDS, SAS, Bf-S and Bf-S. Plasma levels were assessed at least twice. The primary efficacy outcome measure was evaluated by the reduction in HAMD score from baseline. Logistic regression analyses of the results revealed no significant association. Therefore, it is unlikely that the functional polymorphism in the monoamine oxidase-A promoter plays a major role in the clinical response to moclobemide.