Doctoral defence: Katrin Tomson-Johanson "Impulsivity, serum lipids and serotonin-related functional gene variants"

On 23 August at 12:00, Katrin Tomson-Johanson will defend her thesis "Impulsivity, serum lipids and serotonin-related functional gene variants".

Supervisor:
Jaanus Harro, University of Tartu

Opponent: 
Dr István Bitter, Semmelweis University (Hungary)

Summary:
Impulsivity, a key feature in several psychological disorders like substance abuse and suicidality, often arises from hasty, ill-considered decisions leading to adverse outcomes. Notably, impulsivity isn't uniformly detrimental; it can be categorized into functional-, which is beneficial under certain conditions, and dysfunctional impulsivity, characterized by a lack of thoughtful decision-making when required. High impulsivity levels have been linked to both lower serotonergic activity and low cholesterol levels.

Current study involving a representative birth cohort from the Estonian Children Personality Behaviour and Health Study examined the complex interactions between cholesterol, genetic markers, and impulsivity from childhood through young adolescence. We found significant associations between the risk genotype of 5-HTTLPR polymorphism and decreased LDL and total cholesterol levels. Interestingly, low cholesterol levels during early childhood predicted high impulsivity in adult males, underscoring cholesterol’s role in developing impulsivity.

Furthermore, the study highlights that the -1438A/G HTR2A polymorphism's A/A genotype correlation with maladaptive impulsivity in 25-year-olds is affected by cholesterol levels. In females, high cholesterol intensifies maladaptive impulsivity, whereas in males, higher cholesterol appears to moderate genotype effects.

Risk behaviours and impulsivity show varying patterns across different ages and sexes, with males showing more adaptive impulsivity and females showing more maladaptive tendencies. Cholesterol levels don’t uniformly influence risk behaviours or suicidal thoughts across genders and ages, though certain profiles in 25-year-old males are linked to increased suicide risk.

The study underscores the importance of considering multiple interacting factors when researching impulsivity. By utilizing a diverse and representative sample, the study provides a broader, more accurate view of how genetic, environmental, and physiological factors converge to influence impulsivity and associated psychiatric conditions. This comprehensive approach offers valuable insights into impulsivity’s complex nature and its implications for mental health, pointing to the need for continued research in this area.