Fluoxetine Appears Effective In Less-Severe Depression

A 12-week regimen of fluoxetine appears to be successful in ameliorating depressive symptoms in patients who do not meet criteria for major depressive disorder.

But improvement in psychosocial functioning with fluoxetine may take longer than 12 weeks in these patients, according to a study in the October American Journal of Psychiatry.

The study suggests that a widely accepted assumption about the usefulness of pharmacologic intervention in subacute or “minor” depression may need to be reversed. That assumption rests on a 1988 study by Paykel and colleagues showing that patients with minor depression did not respond significantly better to the antidepressant amitriptyline than to placebo. It was published in the January 1988 Pharmacopsychiatry.

The new study was conducted by Lewis Judd, M.D., chair of the department of psychiatry at the University of California, San Diego, and researchers at four other institutions and Eli Lilly and Co. in Indianapolis.

It was supported in part by grants from the National Institute of Mental Health, the Roher Fund of the University of California, San Diego, and an unrestricted investigator-initiated contract from Eli Lilly and Co., which manufactures the Prozac brand of fluoxetine.

In the study, 162 patients with minor depressive disorder were randomly assigned to receive fluoxetine or placebo in a 12-week, double-blind study; of those, 59 in each treatment group completed the study. At baseline, all patients were mildly to moderately depressed with a corresponding degree of functional impairment.

Over the 12-week period, the fluoxetine group showed significantly greater improvement in scores on the 30-item clinician-rated Inventory of Depressive Symptomatology, the 17-item and 21-item Hamilton Depression Rating Scale, the Beck Depression Inventory, and the Clinical Global Impression severity scale.

However, the fluoxetine group did not improve more than the placebo group on any of three measures of psychosocial functioning. Those measures included the Global Assessment of Functioning (GAF) Scale and the social function and emotional role function scores on the Medical Outcomes Study 36-Item Short Form Health Survey. But secondary statistical analysis showed that the rate of improvement—though not the absolute score—on the GAF measure was significantly greater in the fluoxetine group than in the placebo group.

“Findings from this rigorously controlled study indicate that minor depressive disorder can be treated successfully with fluoxetine, but full normalization of associated psychosocial function may require longer treatment,” the authors wrote. “It is also likely that other SSRIs or newer non-SSRI antidepressants might produce similar results under similar experimental conditions.”

The study, “Randomized, Placebo-Controlled Trial of Fluoxetine for Acute Treatment of Minor Depressive Disorder,” is posted online at<http://ajp.psychiatryonline.org/cgi/content/full/161/10/1864>.▪

Am J Psychiatry 2004 161 1864