NEW YORK (Reuters Health) Dec 27 - More than a third of patients with obsessive-compulsive disorder (OCD) who are receiving recommended doses of selective serotonin reuptake inhibitors (SSRIs) do not perceive sustained long-term benefit from the treatment, according to a new study. Further, few OCD patients receive the recommended doses of cognitive-behavioral therapy (CBT).

"Significant advances have been made in the treatment of OCD, a common and frequently debilitating psychiatric disorder," Dr. Maria C. Mancebo and colleagues from Brown University Medical School, Providence, Rhode Island, write in a study published in the November issue of the Journal of Clinical Psychiatry. "The short-term efficacy of pharmacotherapy and behavioral interventions for OCD is well established."

In the current study, the researchers studied 293 adults with primary OCD who were enrolled in the Brown Longitudinal Obsessive Compulsive Study. The team collected data at intake interviews between June 2001 and October 2004. The Clinical Global Impressions-Improvement Scale-patient version was used to assess patient impressions of response.

Overall, 182 subjects (78%) were taking recommended doses of SSRIs at intake. Of these, 112 (62%) rated themselves as being very much or much improved. The remaining 70 subjects rated themselves as minimally improved, unchanged, or worse while taking the recommended doses of SSRIs. These patients had been receiving their current SSRIs for a mean of 2.7 years.

Forty-two subjects were receiving SSRIs and a neuroleptic augmentation. Of these, 12 (29%) reported a response.

A total of 111 patients (38%) received at least the recommended 13 lifetime sessions of CBT. Although the mean number of sessions was 37, only 71 patients (24%) reported completing a continuous course of 13 weekly sessions.

Of 27 patients who received a course of CBT in the past year, 18 (67%) rated themselves as very much or much improved. Sixty-eight percent of patients who received the recommended course of 13 weekly sessions rated themselves as responders, compared to 47% of those who received less than the recommended dose (p < 0.015).

"In conclusion, this study documents the need for a better understanding of how evidence-based treatments for OCD are used in clinical settings, as well as the long-term-durability of effects," Dr. Mancebo's team writes.

"Further studies of treatment effectiveness using controlled treatments in naturalistic settings are needed in order to understand whether intensive exposure and ritual prevention delivered by nonexpert therapists show similar effects to those of clinical trials," they suggest.