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Schizophrenia Drugs Linked to Diabetes

Evidence Mounts That Newer Schizophrenia Medications Boost Blood Sugar
WebMD Health News

June 3, 2003 -- Newer schizophrenia medications have largely taken care of the nerve and muscle side effects associated with older drugs. But evidence is now mounting that some of these newer medications boost blood sugar levels and may lead to diabetes.

"It's really a substitution of one side effect for another," Michael J. Sernyak, MD, of the Yale School of Medicine, tells WebMD. "Because of the newer 'atypical' drugs, the days are gone when people literally became as rigid as a board from schizophrenia drugs."

In a new study of 121 people with schizophrenia, Yale researchers found that close to 25% of them developed high blood sugar levels while taking Clozaril, the first of these newer schizophrenia medications -- called "atypical antipsychotics."

The high blood sugar levels put them at risk of developing diabetes in the future. But the study's lead researcher says it's not an indictment of this or other newer schizophrenia drugs, which are now the first-line defense in treating schizophrenia.

Rather, his study -- and other research -- suggests that schizophrenia patients and their doctors need to be especially vigilant against diabetes during treatment.

What's the Real Cause?

But is it schizophrenia drugs that boost diabetes risk -- or schizophrenia itself?

"Apart from the drugs, schizophrenia by itself is associated with a higher frequency of diabetes than what is seen in the general population," says psychiatrist David Garver, MD, of the University of Louisville School of Medicine and a spokesman for the American Psychiatric Association.

"We don't know the exact reason, but the association is clear. So with any drug taken for schizophrenia, or with the condition itself, you are going to see a greater risk of diabetes than in people without the illness."

In fact, some studies suggest that people with schizophrenia have a four- to six-fold risk of diabetes compared with the general population -- and the rates are highest among those under age 40.

One possible explanation: Those with schizophrenia typically have higher levels of cortisol, known as the "stress hormone," because the body releases it during times of agitation. And high coristol levels can cause problems in the way blood sugar is metabolized, says Sernyak.

So What Now?

"If you realize this risk is hanging over your head, you need to try every way you can to prevent the development of diabetes. That means addressing things like weight gain or being overweight, and exercising, not smoking, and watching your diet," Sernyak says. "And patients receiving these drugs should really be treated as being at relatively high risk of developing diabetes."

His study, published in the May issue of the Journal of Clinical Psychiatry, follows previous research -- including some of his own -- linking Clozaril with a higher risk of diabetes.

In a review of 38,000 schizophrenics, Sernyak reported in the American Journal of Psychiatry last year that those taking Clozaril were 25% more likely to develop diabetes than those receiving other drugs. And a Swedish study indicated that patients taking Clozaril were more than twice as likely to develop diabetes than those taking other schizophrenia medications.

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