A commonly used psychiatric drug shrinks brains

Haldol reduces brain size dramatically just two hours after an injection. As the heading in a Nature News story runs, Antipsychotic deflates the brain.

Just two hours after injection with haloperidol, an antipsychotic commonly prescribed to treat schizophrenia, healthy volunteers experienced impaired motor abilities that coincided with diminished grey-matter volume in the striatum — a brain region that mediates movement.

These changes have been observed physically taking place in the functional magnetic resonance imaging (fMRI) scans of healthy participants who voluntarily took the drug.

Lindenberg, professor of psychiatry and psychotherapy at the University of Heidelberg in Mannheim, Germany, and a lead author on the report in Nature Neuroscience. “Studies have found that the volume of brain regions changes over a number of days, but this is in one to two hours, and in half that time it bounces back.”

If the brain were an accordion, this finding wouldn’t be so worrisome. Not being designed for rapid inflation and deflation, I would have some tribidation about putting anybody on a drug that shrunk brain area sizes so dramatically. The brain of nature isn’t a brain of rubber either, and so when it bounces back, there is always going to be a question as to whether all of it bounced back.

The findings may also hint at why people with bipolar disorder have reduced grey matter in parts of their brains after manic mood swings. Andrew McIntosh at the University of Edinburgh, UK, says that the connection between the brain-shrinking effects of an antipsychotic reported in this study and the grey-matter reduction he and others have observed in schizophrenic and bipolar patients is “a bit uncertain but this paper definitely makes this worthy of further investigation”.

This is not the only study, by the way, indicating that some of the loss of gray matter often attributed to “serious mental illness” may actually be caused by the psychiatric drugs used to treat such maladies.