To Be Or Not To Be: Is OCD an Anxiety Disorder?

OCD used to be classified as an anxiety disorder. However, in the most recent update to the Diagnostic and Statistical Manual (DSM-5), OCD has been moved to a new category, the Obsessive-Compulsive and Related Disorders (OCRDs). Does this mean that OCD is not based in anxiety? Does this impact how we treat OCD? Let’s look at how this change in classification impacts clinical practice and decisions about treatment. We’ll start with the basics and go from there…

How is OCD defined? The primary diagnostic criteria for OCD remain largely the same in the new DSM-5. OCD requires the presence of obsessions (intrusive thoughts, urges, or images that cause distress) and/or compulsions (repetitive behaviors or mental acts that are performed in response to obsessions). In reality, virtually all patients with OCD experience both obsessions and compulsions. This is because OCD is maintained by a vicious cycle in which 1) an obsession arises, 2) the individual feels discomfort and is compelled to resist the obsession through ritualized behavior, distraction, or neutralization, and 3) the individual feels a (temporary) relief from his/her discomfort after performing the compulsion. Although only short-term, this immediate relief reinforces the cycle so that the individual’s compulsive behaviors become habitual. Furthermore, by repeatedly escaping the obsession through reliance on compulsions, the individual does not get the opportunity to test or correct faulty appraisals. This leads to continued fear when the obsession recurs and explains why obsessions and compulsions go hand in hand.
What was the rationale for moving OCD to a new category? The cycle described above is similar to the anxiety-avoidance cycle that is characteristic of anxiety disorders more broadly. And the DSM-5 acknowledges that there is a close relationship between OCD and the anxiety disorders. Why then move OCD out of the Anxiety Disorders category? The DSM-5 notes that OCD shares certain core features with the other OCRDs – Trichotillomania (Hair-Pulling Disorder), Excoriation (Skin-Picking Disorder), Hoarding Disorder, and Body Dysmorphic Disorder. Specifically, repetitive behavior is thought to be a hallmark symptom of this group of disorders.
What do clinicians need to know about the new OCRD category? For the answer to this (and the next) question, we turn to recent publications by Jonathan Abramowitz and Ryan Jacoby at the University of North Carolina at Chapel Hill. They note that while the disorders in this category do share repetitive behavior of some kind, the nature of the behavior varies across disorders. In OCD and Body Dysmorphic Disorder (BDD), repetitive behavior reduces distress, while in Trichotillomania and Excoriation, it contributes to pleasure or gratification. Essentially, it is the difference between “compulsive” (risk aversion) behavior and “impulsive” (pleasure-seeking) behavior.
How does this distinction impact treatment considerations? Abramowitz and Jacoby note that since the function of the repetitive behaviors seen in Obsessive Compulsive and Related Disorders is different, the recommended treatment will be different. While exposure therapy (and Exposure and Response Prevention specifically) is effective in treating OCD and BDD, it is not recommended for Trichotillomania and Excoriation because of the absence of a fear-based trigger and a fear-avoidance response. Instead, the effective treatments for these two latter disorders are Habit Reversal Training and Stimulus Control.
So, is OCD an anxiety disorder? No, according to the DSM-5, as it shares stronger similarities with the OCRDs. However, there remain strong similarities between OCD and anxiety disorders. Most notably, OCD is maintained by an anxiety-avoidance cycle and responds to exposure-based interventions. Changes in the DSM often bring about helpful insights and greater clarity for practicing clinicians. In the case of re-classifying OCD into the OCRD category, it also requires clinicians to carefully evaluate the function of repetitive or compulsive behavior in order to choose the appropriate form of treatment.
 
References:
Abramowitz, J. & Jacoby R. (2014). Obsessive-Compulsive Disorder and the DSM-5. Clinical Psychology: Science and Practice, 21, 221-235.
Abramowitz, J. & Jacoby R. (2014). The Use and Misuse of Exposure Therapy for Obsessive-Compulsive and Related Disorders. Current Psychiatry Reviews, 10, 273-283.