No abstract

Increasing amounts of data suggest that affective disorders might be related to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, one of the stress-response systems. Arginine vasopressin (AVP) influences several symptoms, relevant to affective disorders, notable memory processes, pain sensitivity, synchronization of biological rhythms and the timing and quality of REM sleep. We examined whether genetic variations in the AVP receptor 1b gene (AVPR1b) could be associated with increased susceptibility to affective disorders using a gene-based association analysis of single-nucleotide polymorphisms (SNPs). Five SNPs were identified in AVPR1b and genotyped in two well-diagnosed samples of patients with recurrent major depression and matched controls. In the Swedish sample, we observed significant allele (P¼0.02) and genotype (P¼0.01) association with SNP AVPR1b-s3, and in the Belgian sample, a borderline significant association with SNP AVPR1b-s5 (P¼0.04). In both patient-control samples, the haplotype defined by alleles A-T-C-A-G for the AVPR1b-s SNPs s1-s2-s3-s4-s5 was significantly over-represented in controls compared to patients. Our data support a protective effect of this major haplotype for recurrent major depression.

Background: Since several studies show season of birth variations in morbidity, suicidal behavior and CSF (cerebrospinal fluid) monoamine metabolites, we investigated season of birth variations in personality in the population. Methods: We analyzed by multiple logistic regressions the Temperament and Character Inventory (TCI) for 2,130 individuals taking part in the Betula prospective random cohort study of Umeå, Sweden. Results: The personality dimensions were correlated significantly with age and gender. We stratified the data according to age, gender and the season of TCI measurement. By the median split in each stratum, a high-value group and a low-value group were obtained for each of the personality dimensions. Those born during February to April were significantly more likely than those born during October to January to have high NS (novelty seeking) among women, particularly the subscale NS2 (impulsiveness vs. reflection), and to have high PS (persistence) among men. Temperament profiles also showed season of birth variations. Conclusions: We discuss the associations in the literature between personality and the monoamines serotonin and dopamine, and suggest that our results are compatible with a hypothesis of season of birth variation in the monoamine turnover. The personality traits are likely to be influenced by several genetic and environmental factors, one of them being the season of birth.