Kelli Lehto „Depression- and anxiety-related gene variants: effects on personality traits and healt-related behaviour“
On 20 February 2015 Kelli Lehto will defence her doctoral thesis „Depression- and anxiety-related gene variants: effects on personality traits and healt-related behaviour“ in the Council of the Faculty of the Social Sciences and Education.
Professor Jaanus Harro, University of Tartu
Professor Zoltan Rihmer, Semmelweis University
Previous findings have indicated that some personality traits are increasing the risk for depression. Personality traits and depression are both to a significant extent heritable and are considered to share some of the genetic components. Unraveling the genetic basis of these phenotypes has proven to be difficult. The purpose of this dissertation was to study the effects of several depression-related gene variants, 5-HTTLPR, BDNF Val66Met, COMT Val158Met and TPH2 G-703T, on personality traits in a large population representative sample. In addition, we aimed to study gene × gene interactions, time and sex as possible modulators, and furthermore, to assess if there are any genotype effects on other health-related behaviours. Indeed, we found that all candidate genes under investigation had influence on personality traits. The COMT genotype was affecting Neuroticism, a trait for excessive worrying and anxiety. The main effects of BDNF and TPH2 gene variants were on Conscientiousness, a trait for dutifulness, precision and self-discipline. In addition, these genotype effects on Conscientiousness were modulated by the 5-HTTLPR polymorphism. Also we found the effects of TPH2 and COMT on Neuroticism to be age-dependent. Although we did not find any genotype effects on the history of mood and anxiety disorders, there were associations with health-related behaviour. We found the BDNF polymorphism to affect the emergence of eating disorder symptoms and COMT polymorphism to influence depressiveness, educational attainment, and also socioeconomic status assessment. The difficulties in unraveling the genetic foundations of personality traits suggest a large number of additional factors, which may modulate the emergence of genotype effects. With these results on a large population representative study, we highlight the significance of considering time, sex and gene × gene interactions as possible modulators of genotype effects.