Gender Differences in the Normal Brain: Implications for Mental Illness

Abstract

A growing literature suggests that gender differences may exist in the human brain that have important implications for physical and mental health as well as the aging process. Magnetic resonance studies from the author's laboratory and others have revealed a variety of structural differences in the brain. As the brain ages, its tissue mass decreases and cerebrospinal fluid increases. This aging process appears to have a less steep slope in women than in men, suggesting that the female brain is slightly less vulnerable to the aging process. Using such functional techniques as positron-emission tomography and single-photon-emission computer tomography. Some investigators have observed a higher baseline rate of cerebral blood flow in women than in men. A large but highly controversial literature suggesting hemispheric specialization in the human brain may indicate that the female brain is somewhat less lateralized in cognitive functions, making it less vulnerable to the effects of injury at all stages of development. These differences in cerebral structure and function have important implications for the understanding of a variety of disease processes that affect men and women, including cerebral vascular disease, dementia, schizophrenia, depression, childhood disorders, and other illnesses. This presentation focuses on the implications for the understanding of schizophrenia, where gender differences have sometimes been noted in brain structure, involving cranial, cerebral, and ventricular size, as well as possible specific differences in such brain regions as the prefrontal cortex. Functional assessments of the brain involving both imaging techniques and neuropsychology also suggest differential patterns of dysfunction in schizophrenia in relation to gender differences. These findings highlight the importance of studying and understanding gender differences in the brain in relation to health and disease.