A 2-year prospective follow-up study of the course of obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) is a common and frequently debilitating psychiatric disorder with considerable burden to both the individual and society in terms of lost productivity. Despite the increased recognition of the public health significance of OCD over the last 2 decades, surprisingly little is known about the long-term course and prognosis of the disorder. Clinical trials of cognitive-behavioral therapy (CBT) and/or serotonin reuptake inhibitors (SRIs), and much less frequently neurosurgery, document sustained effects of treatment.1–6 Prospective, observational studies of illness course have several advantages over follow-up studies of treatment trials. Most treatment trials, due to sample size, have limited power to address the likelihood of remission and relapse over time or which clinical characteristics affect these probabilities. Efficacy studies also have more stringent inclusion criteria and often exclude comorbid disorders such as depression, substance abuse, personality disorders, and medical problems, limiting the generalizability of the sample. Observational studies of illness course are designed to detect patterns of remission and relapse in representative clinical samples. These studies, which now exist for the other psychiatric disorders, have added valuable, new, unanticipated information on prognosis, patterns of remission and relapse, factors affecting these patterns, and the underutilization of effective treatments.7–11 Early retrospective reports of OCD course suggested the illness is usually chronic and lifelong.12 In contrast, a study by Skoog and Skoog13 on the course of OCD in 144 inpatients treated prior to the introduction of current OCD treatments reported low remission rates within the first decade (11% full remission; 17% partial remission) but slightly higher rates at the 40-year follow-up (20% full remission; 28% partial remission). Despite these low remission rates, two-thirds of the inpatients were improved within a decade after onset of OCD, and 83% were improved at the 40-year follow-up. Course findings from studies of adults with OCD conducted since the 1990s, when effective treatments of OCD (namely, CBT and SRIs) became widely available, have been inconsistent.4,14–19 Four prospective studies in particular have reported on the long-term course of treatment-seeking adults with OCD in naturalistic clinical settings.14–16,18 Rates of achieving at least partial remission (subclinical OCD symptoms) range from 52% of 66 outpatients treated over a 2-year prospective period in a US OCD specialty clinic15 to 76% of 75 patients followed up 11–13 years after initial treatment at a psychiatric hospital in India.18 Rates of full remission (no OCD symptoms) in these studies range from 17%15 to 43%.18 Differences in methodology may account for some of the variability in remission rates across studies. For example, in the study conducted by Reddy and colleagues,18 the majority of subjects were drug treatment–naive at study intake. All but one study were limited by small sample sizes,15,16,18 and the study with the largest sample size (N = 100) comprised patients ascertained for an anxiety disorder other than OCD.14 This article presents the first 2 years of longitudinal observation from the Brown Longitudinal Obsessive Compulsive Study (BLOCS). In this prospective study, we followed 214 patients whose primary reason for seeking clinical treatment was OCD and who reported that OCD was the most problematic disorder over their lifetime. On the basis of previous findings,13,15 we hypothesized that a substantial proportion of subjects would improve to the point of partial remission (subclinical symptoms), but full remission (no symptoms) would be observed less frequently. On the basis of our clinical experience and a review of putative predictors of outcome in OCD,17,19–21 we also hypothesized that greater symptom severity and the presence of hoarding as principal obsession would be associated with a lower likelihood of remission of OCD. Finally, consistent with previous findings that poor insight in OCD does not predict treatment response,22 we hypothesized that the presence of poor insight would not be associated with likelihood of remission.