Psychiatric drugs shrink patients' brains
Alarming study has given a double meaning to the idea of going to see the shrink.
Tue, Feb 08 2011 at 7:11 PM
Researchers have long known that people with schizophrenia have smaller brains by volume than the general population, especially in the "grey matter" structures of the brain which deal with memory storage and higher reasoning. But a shocking new study has revealed that the antipsychotic drugs administered to mental health patients to "treat" them may actually be partly to blame for that brain volume reduction, according to Nature.
The study could have serious implications about the appropriate use of antipsychotic drugs, as well as complicate theories about how exactly these drugs are purported to work.
The research was led by Beng Choon Ho, a psychiatrist and neuroscientist at the University of Iowa in Iowa City. Using magnetic resonance imaging (MRI) to scan the brains of 211 patients diagnosed with schizophrenia over a 7.2-year period, with an average rate of 3 scans per patient, Ho's team found that antipsychotics explained 6.6% of the reduction in total brain volume and 1.7% of the change in total grey-matter volume.
Although the study is marred by the lack of a placebo control group (such a control would be unethical, since patients can't be deprived of the medications they may need), there are a number of facts from the study which reinforce its results nonetheless. For instance, the more antipsychotics that patients receive, the more likely they are to have a decreased amount of grey matter. The study also found that the greatest volume reduction came in those who had been recently diagnosed, meaning they had just started taking their medication.
In other words, the use of antipsychotic medication appears to be directly correlated with the advent of the brain loss.
Further corroboration for these results comes from animal studies, where there are fewer ethical considerations. For instance, one study by neuroscientist David Lewis found that healthy non-human primates given doses of antipsychotics similar to those given to humans showed brain volume reductions of around 10 percent.
"We did not expect to see this," said Ho. "We've been very careful to get it right because of the potential implications."
One such implication is that the antipsychotic drugs examined in Ho's research are helping patients by hurting them-- a paradoxical fact which ought to caution mental health officials about the real value of these drugs.
According to Lewis, the next step for researchers could be to study people with depression and bipolar disorder, too. Comparing changes in the brain volume of these patients, who are prescribed many other types of psychiatric drugs besides antipsychotics, to the changes among patients from Ho's study, could spell out just how far these concerns span.
In the meantime, Ho recommends that doctors exercise increased caution whenever prescribing antipsychotics.
"This will reinforce what I have always tried to do with my patients-- work with them in finding the lowest effective dose," he said.
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