Chronic Anxiety Requires Long-Term Treatment to Prevent Relapse

Fran Lowry

December 16, 2010

December 16, 2010 — Patients with chronic generalized anxiety disorder (GAD) who are receiving antidepressant therapy need to be continuously treated for at least 12 months to prevent relapse, according to a new study.

"Clinicians should not be afraid to treat their chronically anxious patients for at least 12 months and probably even longer," lead study author Karl Rickels, MD, Stuart and Emily Mudd Professor of Psychiatry at University of Pennsylvania, Philadelphia, told Medscape Medical News.

"Full remission of symptoms should be the treatment goal, and this goal is not reached for many patients unless they are treated for at least 6 months."

The study is published in the December issue of the Archives of General Psychiatry.

There were very few data on long-term treatment of GAD with medication and no data at all on whether 12 months of treatment was better than 6 months of treatment, Dr. Rickels explained.

Therefore, he and his team set out to examine the long-term efficacy of treatment with venlafaxine extended release (XR) in patients with chronic GAD who had responded therapeutically to an initial 6-month course of venlafaxine XR treatment.

The 18-month study was composed of 3 treatment phases: a 6-month, open-label, venlafaxine XR, flexible-dose treatment phase, which included 268 patients; a 6-month, randomized, double-blind, placebo-controlled relapse phase, which included 136 (50.7%) of the open-label patients; and a final 6-month, randomized, double-blind, placebo-controlled relapse phase, which included 59 (43.4%) of the first relapse phase patients.

The study showed relapse rates in phase 2, or at months 6 through 12 of the study, were 9.8% for patients taking venlafaxine XR compared with 53.7% for patients taking placebo (P < .001).

Relapse rates after 12 months of venlafaxine XR treatment were 6.7% for patients who were taking venlafaxine XR for the full 18 months, 20.0% for patients taking placebo for 12 months (months 6 to 18), and 32.3% for placebo patients who switched at month 12 to placebo (P < .14).

The study also found that patients treated with venlafaxine XR for 12 months before being shifted to placebo experienced a lower relapse rate (32.4%) than patients shifted to placebo after taking venlafaxine XR for only 6 months (53.7%; P < .03).

A major limitation of the study was its high attrition rate, said Dr. Rickels.

"Only patients who are willing to take medication for their anxiety for an extended period of time, who are able to cope with the adverse events that may occur, and who are able to cope with the slow onset of improvement and are willing to go up to the highest doses of drug allowed by the [US Food and Drug Administration], will benefit from long-term treatment," he said. "This excluded 40 patients in our study who dropped out of treatment before completing at least 6 weeks of treatment."

Dr. Rickels said that patients particularly suited to long-term treatment are those patients who have had anxiety for several years and whose anxiety clearly affects their quality of life.

Commenting on the study for Medscape Medical News, Richard Steinbook, MD, professor of psychiatry at University of Miami Miller School of Medicine in Florida, said the study confirms clinical experience.

"This study confirms what we have always experienced clinically on a more scientific basis. Now we can say with more scientific certainty that these patients do require longer term treatment."

He also approved of the study design.

"This was a relapse prevention study. It gave patients the opportunity to compare themselves over the long haul with others who have been switched to placebo," Dr, Steinbook said.

"Dr. Rickels has been one of the mainstays in this area. He has spent over 30 years working with this group in a variety of treatment approaches. This is a useful study."

This study was supported by the US Public Health Service. Wyeth Pharmaceuticals Inc provided all study medication. Dr. Rickels reports financial relationships with Cephalon Inc, Hoffman-LaRoche Inc, Jazz Pharmaceuticals, Johnson & Johnson, Novartis Pharmaceuticals, Pfizer Inc, Epix (PreDix) Pharmaceuticals, PGxHealth LLC, Genaissance Pharmaceuticals Inc, Pamlab, Pfizer Inc, Wyeth, Boehringer Ingelheim, and Neuropharm. Dr. Steinbook has disclosed no relevant financial relationships.

Arch Gen Psychiatry. 2010;67:1274-1281. Abstract


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