Thyroid hormones and personality traits in attempted suicide

The research on thyroid hormones and personality traits is quite sparse and mainly focused on male forensic psychiatric populations in which the relationship between thyroid hormones and psychopathy and aggression-related personality traits has been reported. The suicidal temperament hypothesis suggests that certain personality traits such as aggression, anxiety proneness, impulsivity, and low socialization may render an individual vulnerable to the risk of suicide. The aim of this study was to investigate personality traits assessed by the Karolinska Scales of Personality (KSP) in relation to hormones in the hypothalamic-pituitary-thyroid (HPT) axis in 100 euthyroid suicide attempters. Standard multiple regression analyses were performed with TSH, T3, T4, and the T3/T4 ratio, respectively, as the dependent variable and KSP factors (Anxiety Proneness, Aggressiveness, and Impulsivity) and subscales (Detachment, Social Desirability, and Socialization) as independent variables. In men, but not in women, the regression model of the T3/T4 ratio was significant and the results suggested that high scores on Aggressiveness and low ones on Detachment were associated with a low T3/T4 ratio. These results indicate that HPT function may be related to Aggressiveness and Detachment in male suicide attempters.