Sexually dimorphic changes in the amygdala in relation to delusional beliefs in first episode psychosis

Background: Few attempts have been made to examine the relationship between amygdala abnormalities and specific symptoms in psychosis. The present study explored the relationship between amygdala morphology and mood congruent and mood incongruent delusional beliefs.
Methods: Amygdala volumes were measured in 43 patients presenting with delusional beliefs in the context of their first episode of psychosis and 43 healthy volunteers matched for age and gender.
Results: Left-greater-than-right-asymmetry of the amygdala varied as a function of gender and mood congruence of delusional beliefs, due to asymmetrical enlargement of the left amygdala in women presenting with predominantly mood incongruent delusions. However, there was no difference in amygdala volumes across groups.
Conclusions: Amygdala abnormalities in women may be associated with aberrant emotional processing that Could contribute to the development of mood incongruent delusional beliefs. Sexually dimorphic changes in the amygdala may contribute to differential phenotypic illness expression in men and women.