But the results leave open the possibility that some medications, including the one in the trial, may still be an effective treatment for certain patients.
More than 1.2 million people in the United States are thought to suffer from kleptomania, the guilt-ridden, impulsive stealing of inexpensive and unneeded items. The condition differs from shoplifting, in which the action is usually planned and motivated by need or monetary gain. People suffering from kleptomania often fail to seek treatment for fear of legal repercussions.
The medication in the trial was escitalopram, marketed as Lexapro. The drug belongs to a class of antidepressants known as selective serotonin reuptake inhibitors, and earlier studies have suggested that SSRIs can be effective in treating some impulse control disorders, such as skin picking. In an earlier, non-blinded open-label phase of the kleptomania study, when trial participants were aware that they were taking escitalopram and not a placebo, 78 percent of the patients responded to the drug.
In the second phase of the study, conducted as a double-blind, placebo-controlled trial, the benefit was not seen.
"When we randomized people to drug vs. placebo, the same proportion of people relapsed on drug as relapsed on placebo, suggesting that it was really a placebo response in the initial phase of the study," said Lorrin Koran, MD, professor of psychiatry and behavioral sciences and first author of the study, which will be published in the March issue of the Journal of Clinical Psychiatry.
In the double-blind trial, 15 subjects were assigned to receive either a placebo or escitalopram . For both groups, the relapse rates were effectively the same, with three of seven patients on the drug relapsing, compared with four of eight on the placebo.
Koran says that the small number of subjects in the study makes it impossible to know with certainty whether the results of the trial are really indicative of the effectiveness of escitalopram.
"For some people, I think these drugs really do work. And for others, maybe not, but until you have large studies you can't tease that out," he said.
Koran emphasized that the results of the clinical trial are not definitive, and some people may be helped by therapy involving medication. For others, receiving psychological treatment, perhaps in combination with medication, may prove most effective. But regardless, he said, "People with this disorder should definitely seek treatment."
This study was funded by Forest Laboratories, which makes and markets Lexapro. Koran has served as a paid speaker for Forest Laboratories, as has second author Elais Aboujaoude, MD, clinical assistant professor of psychiatry and behavioral sciences and director of Stanford's Impulse Control Clinic. Nona Gamel, clinical research manager, was also a co-author on the study.
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