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Serotonin 5-HT2A receptor (S-HT2A) binding is reported to be altered in individuals with suicidal behavior, mood disorders, and aggressive-impulsive traits. Genetic association with major depression, suicidal behavior, and aggressive-impulsive traits has not been established. This study examines the possible association of the 5-HT2A gene C102T polymorphism with the receptor binding kinetics, and clinical overt phenotypes. The study population included 63 healthy volunteers and 152 subjects with mood disorders, 56 of whom had a history of suicide attempts. All were Caucasian. Platelet 5-HT2A binding kinetics (Bmax and KD) were assayed and adjusted for seasonal variation. All subjects were genotyped for the T102C polymorphism. Clinical phenotype was determined by structured clinical interview. The IT genotype was associated with higher Bmax in all subjects (F =3.53, df = 2,211; p = 0.03), controlling for diagnosis. Bonferroni-adjusted post hoc testing showed higher binding in the VT compared with TC genotype in the control group (F = 7.56, df = 2,60, p = 0.001), but not in the mood-disordered subjects. No difference was found in genotype and allele distribution between the mood-disordered subjects, with and without suicide attempt history, and controls. Bmax was not related to a diagnosis of mood disorders. The TT genotype appears associated with higher platelet 5-HT2A Bmax in the healthy population, but this genotypic effect appears absent in mood disorders and unrelated to psychopathology. [ABSTRACT FROM AUTHOR]

Background: Seasonal variations in onset of mood disorders and in serotonergic function are reported, but their relationship is unclear. Methods: Circannual variation in platelet 5-HT2A binding was measured in 68 healthy subjects and 121 patients with a major depressive episode. In 73 patients the current episode began during Spring or Fall. Results: Significant, but different, circannual variations were found in patients compared with controls. Controls had two peaks of Bmax, one in Spring and another in Fall. Fall and Winter KD was 41% lower compared with Spring and Summer KD. Patients had a peak of Bmax in early Spring and a lesser one in late Fall. Bmax during Spring and Fall was 12% higher compared with Winter and Summer. KD was higher during October through February compared with the rest of the year. Bmax in patients was higher compared with controls in March. The opposite difference was observed in September–December. These differences from controls were mostly due to patients with an onset of the current major depressive episode during Spring or Fall. Conclusions: Patients with a major depressive episode differed from controls in circannual variation of platelet 5-HT2A binding. This may reflect a vulnerability to seasonal effects in patients with mood disorders. [Copyright &y& Elsevier]