Antipsychotics are increasingly prescribed for bipolar disorder in place of mood stabilizers, according to a new study, but research to validate their superior effectiveness remains to be done.

In 1998, 18% of treatment visits for bipolar disorder resulted in prescription of an antipsychotic drug, according to “Trends in use of second-generation antipsychotics for treatment of bipolar disorder in the United States, 1998-2009” (Psychiatric Services, January 2012). By 2009, the figure was 49%.

More precisely, in the 12 months after the FDA in 2000 approved olanzapine for bipolar disorder, its use increased by 92%, and use of other second-generation antipsychotics rose 42%. Meanwhile, prescription of mood stabilizers such as lithium dropped from 82% to 67% of treatment visits for the same years, the study found. And by 2009, more than half of all the treatment visits reviewed for the study produced a prescription for an antipsychotic but no mood stabilizer.

Antipsychotics have become the largest single source of profit for the pharmaceutical industry, grossing an estimated $14 billion in profits a year. The vast majority of these dollars are generated by second-generation antipsychotics, which are still patent-protected. Despite their widespread use, these drugs are controversial: They are substantially more expensive than older, first-generation antipsychotics such as Haldol and loxapine; their side effects include life-shortening conditions such as morbid obesity and diabetes; and little evidence of their effectiveness has been produced. (For a new study of the biological mechanisms that may cause antipsychotics to produce obesity, see "How antipsychotic medications cause metabolic side effects such as obesity and diabetes," Molecular Psychiatry, Jan.31).

“Currently, there is little high-quality scientific evidence that second-generation agents are superior to less expensive first-generation antipsychotics and mood stabilizers in the treatment of bipolar affective disorder,” the four co-authors wrote. The lack of research reflects in part the “limited economic incentive” for pharmaceutical companies to study the effectiveness of expensive second-generation antipsychotics with generic first-generation drugs that have lost patent protection."  

“The magnitude and rapidity of the changes we describe reinforce the importance of studies that compare the benefits and side effects of second-generation,” the authors conclude.

An estimated 2.2 Americans suffer severe bipolar disorder, and about half of them are not in treatment in any given 12-month period. Side effects are commonly blamed for non-adherence to prescribed medications. For these patients, their family members and the communities where they live, research into medication effectiveness cannot come soon enough.

This study was based on a nationally representative audit of office-based physicians. The full text of the report is available only to subscribers of Psychiatric Services. For an abstract, click here. For a related blog, read "The Emerging 'Crisis in Medication Development.'"

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