title: Relationship between blood serotonergic variables, melancholic traits, and response to antidepressant treatments.
abstract: The relationship between peripheral serotonergic variables, melancholic traits, and clinical improvement after antidepressant treatment was examined in 83 drug-free major depressive patients. Plasma serotonin (5-HT) concentrations was lower in untreated melancholic patients (1.00 +/- 0.11 vs. 1.84 +/- 0.28 ng/mL, p < 0.008; N = 40 and 43, respectively). A tendency was observed for plasma 5-hydroxyindoleacetic acid (p < 0.06), whereas platelet 5-HT and plasma tryptophan did not differ between groups. After blood sampling and clinical ratings, treatment began with fixed doses of 5-HT uptake inhibitors (clomipramine or fluvoxamine), monoamine oxidase inhibitors, or tianeptine, a 5-HT uptake enhancer. There was no significant difference in response rates between patients with and without melancholic traits. The relationship between the clinical response at 6 weeks (>50% reduction of baseline Hamilton score) and the pretreatment values of biochemical variables was examined. Responders had a lower pretreatment platelet 5-HT (530 +/- 36 vs. 664 +/- 50 ng/10(9) platelets, p < 0.03; N = 44 and 39, respectively). Patients with a platelet 5-HT concentration above 800 ng/10(9) platelets had a lower response rate than those below this value (p < 0.003). This difference was maximal in the subgroup of patients treated with 5-HT uptake inhibitors (N = 49). In this subgroup, the response rates of patients with 5-HT concentrations below and above the cutoff point were, respectively, 70% and 17% (p < 0.001). A pretreatment platelet 5-HT value above 800 ng/10(9) platelets had a predictive value for a negative response of 92%. These results suggest the presence of biochemical differences in the peripheral serotonergic system between melancholic and nonmelancholic patients. The inverse relationship between the pretreatment platelet 5-HT content and clinical response may be useful in the investigation of the relationship between the 5-HT system and antidepressant response.
authors.affiliation: Department of Neurochemistry, Instituto de Investigaciones Biomédicas de Barcelona, CSIC, Barcelona, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Pérez
authors.forename: N
authors.initials: N
authors.lastname: Bel
authors.forename: P
authors.initials: P
authors.lastname: Celada
authors.forename: J
authors.initials: J
authors.lastname: Ortiz
authors.forename: E
authors.initials: E
authors.lastname: Alvarez
authors.forename: F
authors.initials: F
authors.lastname: Artigas
mesh_terms: D000328:Adult; D000928:Antidepressive Agents / Q000627:therapeutic use*; D001792:Blood Platelets / Q000378:metabolism; D002997:Clomipramine / Q000627:therapeutic use; D003866:Depressive Disorder / Q000097:blood* / Q000188:drug therapy; D003865:Major Depressive Disorder / Q000097:blood / Q000188:drug therapy; D005260:Female; D016666:Fluvoxamine / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012701:Serotonin / Q000097:blood*; D013841:Thiazepines / Q000627:therapeutic use; D014364:Tryptophan / Q000097:blood
chemical_list: D000928:Antidepressive Agents; D013841:Thiazepines; C050504:tianeptine; D012701:Serotonin; D014364:Tryptophan; D002997:Clomipramine; D016666:Fluvoxamine