SSRIs antidepressant activity is influenced by Gβ3 variants

The aim of the present study was to test a possible effect of the G-protein beta3-subunit (Gbeta3) C825T gene variant on the antidepressant activity of selective serotonin reuptake inhibitors (SSRIs) in a sample of major and bipolar depressives, with or without psychotic features. Four hundred and ninety inpatients were treated with fluvoxamine 300 mg/day (n=362) or paroxetine 40 mg/day (n=128) and either placebo or pindolol in a double-blind design for 6 weeks. The severity of depressive symptoms was weekly assessed with the Hamilton Rating Scale for Depression. Gbeta3 allelic variants were determined in each subject using a PCR-based technique. Subjects with Gbeta3 T/T variants showed better response to treatment (P=0.009) and this effect was independent from analyzed demographic and clinical variables. These results confirm preliminary reports and shed further light on the genetics of the response to antidepressant treatments. (C) 2003 Elsevier Science B.V./ECNP All rights reserved.