Quantitative trait loci for neuroticism: an allelic association study with the serotonin receptor (HTR2) and monoamine oxidase A (MAOA) genes

Neuroticism is an important liability factor for the development of anxiety and depressive disorders. Genetic studies of these disorders might be more profitably focused on this liability trait than on the disorders themselves. Quantitative genetic studies have shown a heritability of ˜ 0.42 for neuroticism. Advances in molecular genetics now make it possible to identify allelic variation at particular loci associated with such quantitative traits. Reported here are the results of an allelic association study of neuroticism with two candidate genes: the serotonin receptor (HTR2) and monoamine oxidase A (MAOA) genes. As a secondary issue, associations with extraversion were also investigated. Elderly subjects aged 70 + participating in a longitudinal study were assessed for neuroticism and extraversion on the first wave of the study and DNA was collected on the second wave, 3.6 years later. Data on both neuroticism and genotype were available for 432 subjects. No associations were found between genotype and either personality trait, despite there being sufficient statistical power to detect small associations.