The vulnerability to mood disorders, impulsive-aggression, eating disorders, and 
suicidal behavior varies greatly with gender, and may reflect gender differences 
in central serotonergic function. We investigated the relationships of gender, 
mood, impulsivity, aggression and temperament to 5HT(2A) receptor binding in 21 
healthy subjects using [18F]altanserin and PET neuroimaging. Binding potentials 
in pre-defined regions-of-interest (ROI) were calculated using the Logan 
graphical method, corrected for partial volume effects, and compared by gender 
with age co-varied. SPM analysis was used for voxel level comparisons. 
Altanserin binding (BP(P)) was greater in male than female subjects in the 
following nine ROIs: hippocampus (HIP) and Lt. HIP, lateral orbital frontal 
cortex (LOF) and Lt. LOF, left medial frontal cortex (Lt. MFC), left medial 
temporal cortex (Lt. MTC), left occipital cortex (Lt. OCC), thalamus (THL) and 
Lt. THL. Differences in Lt. HIP and Lt. MTL remained significant after 
Bonferroni correction. Gender differences were noted in the co-variation of 
psychological traits with BP(P) values in specific ROIs. Among males alone, 
aggression was negatively correlated with BP(P) values in Lt. LOF and Lt. MFC, 
and Suspiciousness positively correlated in LOF, Lt. LOF and Lt. MFC. Among 
female subjects alone, Negativism was positively correlated with BP(P) values in 
HIP, and Verbal Hostility in Lt. HIP. Altanserin binding in Lt. MTC was 
positively correlated with Persistence, with no significant gender effect. 
Gender differences in 5HT(2A) receptor function in specific ROIs may mediate 
expression of psychological characteristics such as aggression, suspiciousness 
and negativism. Future studies of 5HT(2A) receptor function and its relationship 
to behavior should control for gender.