1. ¹Department of Pharmacology and Psychiatry, Faculty of Medicine, University of Extremadura, Badajoz, Spain
2. ²University of Beira Interior, Faculty of Health Sciences, Covilhã, Portugal
3. ³Department of Psychiatry, University of Debrecen, Medical and Health Science Center, Debrecen, Hungary
4. ⁴Mérida Psychiatric Hospital, Mérida, Spain

Correspondence: A LLerena, Faculty of Medicine, University of Extremadura, Av. de Elvas, Badajoz s/n E-06071, Spain. Tel/Fax: +34 924 289467; E-mail: allerena@unex.es

Received 6 May 2003; Revised 19 June 2003; Accepted 24 July 2003.

Abstract

Alteration of monoaminergic neurotransmission has been implicated in the pathophysiology of mood disorders, and CYP2C9 enzyme activity has been shown to be modulated by serotonin in vitro. The present study was aimed at analysing the frequency of CYP2C9 alleles (^*1, ^*2, ^*3) among patients suffering from major depressive disorder. In all, 70 such suffering psychiatric outpatients were studied. The CYP2C9 genotypes were determined by allele-specific PCR. The CYP2C9^*3 allele frequency was higher (P<0.01) among the patients suffering from major depression than in a population of 89 schizophrenic patients (odds ratio=3.3) and 138 healthy volunteers (odds ratio=2.8). The results suggest that CYP2C9 genetic polymorphism may be related to a major depressive disorder due to an alteration in endogenous metabolism, although a linkage between CYP2C9 and some other gene related to depression cannot be ruled out.