Antidepressants' effectiveness may vary according to severity of depression.

Moral of the story: Antidepressants may not be useful for all patients with depression.

Source: AMA Morning Rounds 1/6/10

Antidepressants' effectiveness may vary according to severity of depression.

The New York Times (1/6, A12, Carey) reports that "some widely prescribed" medications "for depression provide relief in extreme cases, but are no more effective than placebo pills for most patients," according to a study published Jan. 6 in the Journal of the American Medical Association. After reviewing "data from previous trials on two types of" medicines, paroxetine (Paxil) or imipramine (Tofranil), researchers found that "their effectiveness varies according to the severity of the depression being treated."

        USA Today (1/6, Rubin) explains that University of Pennsylvania researchers "pooled data from six trials in which a total of 718 depressed patients were randomly assigned to take either an antidepressant or a placebo." After obtaining "patient-specific data from scientists involved with each trial," the team found that "antidepressants were more effective than a placebo only for patients with very severe depression, who made up 40% of trial participants but...represent fewer than 30% of depressed people who seek treatment in the real world."

        While "antidepressant medications probably provide little or no benefit to people with mild or moderate depression," the Los Angeles Times (1/6, Roan) reports that the study also suggests that "the mere act of seeing a doctor, discussing symptoms, and learning about depression probably triggers the improvements many patients experience while on medication." Meanwhile, "other research has also found that antidepressants are most effective for severe symptoms, said" Philip Wang, MD, PhD, deputy director of the National Institute of Mental Health. While antidepressants may not "work well for mild to moderate depression, it's also possible that people enrolled in antidepressant studies have robust placebo responses that mask some of the impact of the medication."

        According to the Wall Street Journal (1/6, Dooren), study author Robert DeRubeis, PhD, pointed out that the majority of studies assessing antidepressant medications included patients with severe depression and that such studies were submitted to the Food and Drug Administration for approval of these medicines. In contrast, because far fewer studies have included patients with mild depression, it remains unclear just how effective antidepressants, such as fluoxetine (Prozac) or paroxetine (Paxil), are in this large patient population.

        Meanwhile, Bloomberg News (1/6, Bennett) reports, "doctors, policy makers, and consumers should be made aware that there's little evidence to show antidepressants will benefit the majority of patients with less severe symptoms," the study authors concluded. Forbes (1/6, Langreth), the Columbus (OH) Dispatch (1/6, Crane), and Reuters (1/6, Stern) cover the story, as did HealthDay (1/5, Gardner), WebMD (1/5, Doheny), and MedPage Today (1/5, Gever).