engleski

Is baseline platelet serotonin concentration a good predictor of the therapeutic response to paroxetine

There is a substantial evidence for the abnormalities in central serotonin (5-hydroxytryptamine, 5-HT) neurotransmission in depression. Serotonin is involved in the pharmacotherapy of depression, since most antidepressant drugs are targeted to affect 5-HT function. Among them, selective serotonin reuptake inhibitors (SSRI) achieve their effect by blocking 5-HT reuptake mechanisms. Platelets might be used as a limited peripheral model for studying the pharmacodynamics of 5-HT in the central serotonergic neurons. The aim of the study was 1) to determine the relationship between baseline platelet 5-HT concentration and therapeutic response to 4-5 weeks treatment with a SSRI, paroxetine (20 mg/day) in 50 nonsuicidal, nonpsychotic female patients with major depression (DSM-IV criteria), and 2) to evaluate whether pre-treatment platelet 5-HT concentration might indicate the therapeutic response to paroxetine. Clinical improvement was defined as a reduction of ≥ 50% in Hamilton Rating Scale for Depression (HAMD) total scores. The results (expressed as means ± SD), were evaluated using one-way ANOVA followed by Tukey's test. Before treatment, responders (26.0 ± 2.1) and non-responders (27.4 ± 2.5) had similar HAMD scores. After treatment, responders (7.0 ± 4.7) had significantly (F=180.9 ; df= 3, 96 ; p<0.001) lower HAMD scores than non-responders (22.0 ± 5.0). Pre-treatment platelet 5-HT concentration (nmol/mg protein) was significantly (F=41.86 ; df=4, 172 ; p<0.001) lower in 34 responders (1.09 ± 0.21) than in 16 non-responders (1.48 ± 0.55). Baseline platelet 5-HT concentration was increased in non-responders when compared to corresponding 77 female drug-free healthy controls (1.18 ± 0.21). Before treatment platelet 5-HT values in responders were similar to values in healthy subjects. Post-treatment platelet 5-HT concentration was similarly decreased in both responders (0.40 ± 0.32) and non-responders (0.60 ± 0.31). The study was open, and included a small number of patients, and needs to be replicated. Since treatment with SSRI is long, costly and one third of the patients do not respond to treatment, there is a search for the possible biological predictor of the therapeutic outcome. Our preliminary data indicate that pre-treatment values of platelet 5-HT in drug-free female depressed patients might have a prognostic value as a biological marker for the treatment response to paroxetine.

baseline platelet serotonin; predictor; therapeutic response; paroxetine

doi:10.1017/S1461145704004547