title: Low baseline serotonin-2A receptors predict clinical response to olanzapine in first-episode schizophrenia patients.
abstract: The purpose of this study was to determine whether platelet serotonin-2A (5-HT2A) binding sites and inositol 1,4,5 trisphosphate (IP3) concentrations before treatment can identify olanzapine-responsive patients. The study included 21 never medicated, first-episode schizophrenia patients (antipsychotic-naïve) and 21 patients with a DSM-IV-TR diagnosis of paranoid schizophrenia who had not received depot antipsychotic treatment in the previous 6 months or oral antipsychotic or antidepressant treatment in the previous 2 months (antipsychotic-free). In the antipsychotic-naïve group, olanzapine responders had a significantly lower number of 5-HT2A receptors and lower IP3 concentrations at baseline than non-responders. The combination of baseline 5-HT2A and IP3 values significantly predicted an improvement in negative symptomatology after 6 weeks of treatment with olanzapine. In the antipsychotic-free group, responders had significantly higher positive and lower negative symptomatology at baseline, together with a reduced number of 5-HT2A receptors. However, basal 5-HT2A receptors or IP3 concentrations did not significantly predict positive, negative or general clinical response. The reported results suggest that platelet 5-HT2A binding might be a trait marker that could help to identify those patients likely to show greater improvement in negative symptomatology after olanzapine treatment.
authors.affiliation: Department of Psychiatry, Hospital San Rafael, and Department of Clinical Chemistry, Ciutat Sanitaria i Universitaria de Bellvitge, Barcelona, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Arranz
authors.forename: Pilar
authors.initials: P
authors.lastname: Rosel
authors.forename: Luis
authors.initials: L
authors.lastname: San
authors.forename: Nicolás
authors.initials: N
authors.lastname: Ramírez
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Dueñas
authors.forename: Josep
authors.initials: J
authors.lastname: Salavert
authors.forename: Meritxell
authors.initials: M
authors.lastname: Centeno
authors.forename: Enrique
authors.initials: E
authors.lastname: del Moral
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D001569:Benzodiazepines / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D001665:Binding Sites; D005260:Female; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000097:blood; D008297:Male; D000077152:Olanzapine; D011237:Predictive Value of Tests; D044402:Receptor, Serotonin, 5-HT2A / Q000097:blood* / Q000378:metabolism; D012559:Schizophrenia / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D013997:Time Factors
chemical_list: D014150:Antipsychotic Agents; D044402:Receptor, Serotonin, 5-HT2A; D001569:Benzodiazepines; D015544:Inositol 1,4,5-Trisphosphate; D000077152:Olanzapine