Metabolic correlates of temperament factors of personality: Gender differences

Abstract

376

Objectives: Gender differences in personality are considered to have biological bases. In an attempt to understand the gender differences of personality on neurobiological bases, we conducted correlation analyses between regional brain glucose metabolism and temperament factors of personality in males and females. Methods: We studied 36 healthy right-handed volunteers with FDG PET. There were 18 males (age, 33.8 ± 17.6 y) and 18 females (age, 36.2 ± 20.4 y). Three temperament factors of personality (novelty seeking (NS), harm avoidance (HA), reward dependence (RD)) were assessed using Cloninger’s 240-item Temperament and Characteristic Inventory within 10 days of FDG PET scan. Correlation between regional glucose metabolism and each temperament factor score was tested using SPM2 (P < 0.01 uncorrected, k=100). Results: In males, a significant negative correlation between NS score and glucose metabolism was observed in the bilateral superior temporal gyri, hippocampus and insula, while it was found in the bilateral middle frontal gyri, right superior temporal gyrus and left anterior cingulate cortex and putamen in females. A positive metabolic correlation with HA score was found in the right midbrain and left cingulate gyrus in males, but in the bilateral basal ganglia in females. A negative correlation with RD score was observed in the right middle frontal and left middle temporal gyri in males, while the correlation was found in the bilateral middle frontal gyri and right basal ganglia and superior temporal gyrus in females. Conclusions: These data demonstrate different metabolic correlates of temperament factors of personality between males and females with most striking differences in areas associated with monoaminergic activities. These results may help understand biological substrate of gender differences in personality and susceptibility to psychiatric illnesses such as depression.