A common figure for the dropout rate of exposure and response prevention (ERP) for people with obsessive-compulsive disorder is about 25%. During one OCD workshop I attended, 2 different presenters insinuated that these high rates of dropout were the result of one particularly overzealous researcher who pushed clients too hard! They suggested that, anecdotally, most people with OCD can tolerate exposure-work reasonably well.
A recent study from Utah State professor Michael Twohig’s lab decided to take a closer look at this.
Meta-Analysis
The researchers collected 21 studies of ERP for OCD and conducted a meta-analysis of dropout rates. In a meta-analysis, researchers try to compute variables in order to compare results across multiple studies with different methodologies.
The researchers looked at refusal of treatment and dropout. They also defined what they called “attrition” as a combination of: a.) people who refuse the treatment (i.e., ERP) altogether; b.) people who begin ERP treatment and dropout prematurely. They noted that few researchers track refusal rates, so this remains an understudied variable.
What they found
The researchers found that overall attrition (refusal + dropout) was 18.7%, 12.0% refused treatment, and 14.7% began treatment before dropping out. They did not find any strong predictors of dropout.
In comparing their results to other published research, the authors observed that the dropout rate of 18.7% is similar to those found for PTSD (18.3%) and major depressive disorder (17.5%) and for cognitive behavioral therapy across disorders (26.2%).
Summary
As many therapists are reluctant to use exposure, this study is important in providing evidence that people with OCD may be as open to ERP as they are to any other evidence-based treatment. This is important because ERP has the greatest research support and many people with OCD struggle to find therapists who offer effective treatment.
If you’d like to read the study yourself, you can download a pdf here.
