Anatomical alterations in the Superior Temporal Gyrus (STG) have been reported in schizophrenia. The STG is one of the most asymmetric and lateralized structure of the brain, and the process of lateralization seems to vary according to gender. Although it has been suggested that patients with schizophrenia do not show normal brain lateralization, only few studies investigated it in the STG considering the effects of sex.

The objective of this study is to evaluate sexual dimorphism in STG volumes in a sample of patients with schizophrenia compared to age-and sex-matched healthy controls.

Seventy-two right-hander males (40 schizophrenia patients and 32 controls) and 45 right-hander females (18 schizophrenia patients and 27 controls) underwent clinical evaluation and a 1.5 T MRI scan. Gray and white matter volumes of regions of interests within the STG were detected, including the Heschl's Gyrus (HG) and the planum temporale (PT).

Female patients with schizophrenia presented a reduction in left PT gray matter volumes (F = 4.58, P = 0.03) and a lack of the normal PT asymmetry index (t = 0.27; P = 0.79) compared to female controls (t = 5.47; P < 0.001). No differences were found between males for volumes or laterality. Also, in patients with schizophrenia STG gray and white volumes negatively correlated with positive symptoms (r = −0.33, P = 0.02 and r = −0.29, P = 0.03 respectively), whereas left PT gray matter volumes were negatively associated to duration of illness (r = −0.27, P = 0.04).

Sexual dimorphism plays a key role on PT in schizophrenia, underlying the importance of gender as a modulator of brain morphology and lateralization of schizophrenia.

The authors have not supplied their declaration of competing interest.