Sex and the Schizophrenic

Using state-of-the-art imaging, a Johns Hopkins University team has identified a brain abnormality in male schizophrenics that could help explain why the disease looks different in men and women.

Men are up to twice as likely to develop schizophrenia, which is characterized by disordered thinking, emotional withdrawal, and hallucinations. The disease also strikes males earlier in life than females, more severely affects their cognitive functions, and isn't as amenable to drugs. Now, Hopkins neuroscientist Godfrey Pearlson says his team has found evidence that schizophrenia is indeed a "sexually dimorphic disorder."

In a study published in this month's American Journal of Psychiatry, the researchers used functional magnetic resonance imaging to compare the size of the inferior parietal lobe (IPL), which is involved in higher cognitive functions such as language, attention, and spatial awareness, in 30 male and female schizophrenics and 30 closely matched controls. They found that the left IPL in male schizophrenics is smaller than the right--the opposite of what is found in normal males--about 16% smaller than normal. There were no significant differences in females.

Another study in the same journal goes a step further: Martha Shenton and colleagues at Harvard Medical School in Boston showed that the size difference is localized in a particular part of the IPL: the angular gyrus, an area associated with word meanings and associations.

Scientists have long puzzled over whether sex differences in schizophrenia are simply "modulations" in how the illness is expressed or are central to its very nature, says Jill Goldstein, a clinical neuroscientist at Harvard Medical School. The Hopkins findings indicate the latter, she says.