Are bipolar people smart?

Bipolar disorder : Manic mood swings can destroy gray matter

With every manic or depressive episode, gray matter in the brain of people with bipolar disorder is destroyed.

This is the result of a study with 21 patients suffering from bipolar disorder, a disease characterized by alternating manic and depressive episodes. The patients' brains were scanned using magnetic resonance imaging at the beginning and at the end of a four-year phase in which each had at least one, and some even six episodes. In all cases, the gray matter in the temporal lobe and cerebellum was reduced compared to the control group. Memory and coordination are associated with this area of ​​the brain.

Patients with multiple episodes during this four-year period showed the greatest differences in gray cell mass. "There is a significant correlation with the number of episodes," says Andrew McIntosh of the University of Edinburgh, author of the article published in the Journal of Biologal Psychiatry (1).

Everyone loses brain mass over time, but this process seems to accelerate in people with certain mental disorders, including Alzheimer's and schizophrenia. Now there is also bipolar disorder.

Scientists had already suspected that bipolar disorder was associated with the loss of gray brain matter, according to Lars Kessing of the University of Copenhagen - this is the first confirmation that they are correct.

Language skills

When McIntosh compared gray matter loss to the patients' speech IQ at the beginning and end of the study, a trend emerged. When gray matter was destroyed, the patient's ability to form words and other language-related skills decreased. McIntosh adds that the effect was not statistically significant - possibly because the study of 21 patients was not large enough.

Gray matter has been associated with intelligence in the past.

McIntosh also investigated whether this effect was drug-dependent - patients with bipolar disorder often receive lithium, antidepressants, or antipsychotics. "The medication doesn't seem to have any effect," he says, but adds that it would be going too far to say that medication has no effect on the brain.

For example, drugs can limit the number of manic or depressive episodes, which is now an important factor when looking at the damage done to the brain.

"This finding suggests that we should do more to prevent manic and depressive episodes," Kessing agrees.

McIntosh's group will now investigate factors that could contribute to gray matter loss. In this context, stress hormones could be considered as well as genetic factors.

Researchers suggest that occasionally being in a bad mood or upset is not enough to destroy the brain. "It's not about just being moody," explains Kessing, "these patients have pretty serious bipolar disorder."

(1) Moorhead, T.W.J. et al. Biol Psychiatry doi: 10.1016 / j.biopsych.2007.03.005 (2007).

This article was first published on July 20, 2007 at [email protected] doi: 10.1038 / news070716-16. Translation: Sonja Hinte. © 2007, Macmillan Publishers Ltd

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