The serotonin transporter 5-HTTPR polymorphism is associated with current and lifetime depression in persons with chronic psychotic disorders.

Variation in the serotonin transporter gene (SLC6A4) promoter region has been shown to influence depression in persons who have been exposed to a number of stressful life events.We evaluated whether genetic variation in 5-HTTLPR, influences current depression, lifetime history of depression and quantitative measures of depression in persons with chronic psychotic disorders. This is an association study of a genetic variant with quantitative and categorical definitions of depression conducted in the southwest US, Mexico and Costa Rica. We analyzed 260 subjects with a history of psychosis, from a sample of 129 families.We found that persons carrying at least one short allele had a statistically significant increased lifetime risk for depressive syndromes (P < 0.02, odds ratio 2.18, 95% CI 1.10-4.20).The 'ss' or 'sl' genotype at the 5-HTTLPR promoter polymorphic locus increases the risk of psychotic individuals to develop major depression during the course of their illness.