The term "Pure O" OCD, or "Pure Obsessional" OCD, was once a popular way to describe a form of Obsessive-Compulsive Disorder dominated by obsessions, without apparent compulsions. The impetus for this was the observation that while most people with OCD had both distressing doubts, and obvious compulsions, like washing their hands or checking locks and fires, some individuals experienced only distressing intrusive thoughts without engaging in ritualistic behaviors. Attentive readers will note that I wrote that this “was” a popular term. That’s because our understanding of OCD has evolved significantly, and most experts now reject the idea that "Pure O" exists.
Obsessive-Compulsive Disorder, as defined in the DSM-5, is characterized by persistent, unwanted thoughts, images, OR urges (obsessions) that cause significant anxiety, along with repetitive behaviors or mental acts (compulsions) performed to reduce this distress. While the manual’s use of the word “or” implies that OCD can present with just obsessions or just compulsions, a consensus has emerged that there are always both obsessions and compulsions.
A crucial insight derived from the ideas of behavioral psychologists such as B.F. Skinner and O.H. Mowrer, is that if there is anxiety, there must be some kind of escape or avoidance behavior maintaining the anxiety, for if not, the person (or animal, as was often the case in the work of Skinner and his contemporaries) would soon learn from experience that there is no real threat and their anxiety would diminish. Escape or avoidance attempts, of which compulsions are one type, prevent this safety learning. Think of a child that resists riding a 2
-wheeler out of fear, or always carries a favored teddy bear in their school bag. Once they confront their fear without avoiding, escaping, or relying on the illusion of safety conferred by the teddy, they end up feeling better. So from a theory perspective, just as smoke indicates fire, obsessions invariably point to compulsions.
However, these compulsions may not be obvious behaviors. They can be internal and mental. For instance, someone with harm-related intrusive thoughts might engage in endless mental review of situations to ensure they haven't hurt anyone, or someone with relationship-focused obsessions might spend hours analyzing their feelings about their partner. Experts in OCD can detect extremely subtle and nearly imperceptible forms of compulsions such as wishing the obsession were gone or even doing therapeutic exposures with the expectation and goal of removing the obsessions. If ever a patient describes anxiety and distress from pure obsessions, OCD specialists are confident it's only a matter of time until they discover the compulsions the patient wasn’t able to report.
This understanding isn't merely academic – it has profound implications for treatment. OCD is maintained through a self-reinforcing cycle where compulsions provide temporary relief from anxiety, ultimately strengthening the obsessions. What many people previously identified as "Pure O" actually involves mental compulsions such as rumination, thought suppression, or mental checking. Even more subtly, behaviors like seeking reassurance, mentally "canceling out" bad thoughts, or performing exposure exercises with the explicit goal of eliminating obsessions can function as compulsions. These mental rituals can be so ingrained and automatic that both patients and less experienced clinicians might miss them entirely.
The path to recovery lies not just in identifying and reducing obvious compulsions, but in fundamentally shifting one's relationship with unwanted thoughts. This means learning to coexist with uncertainty and discomfort rather than struggling against it. Effective treatment involves helping individuals recognize and resist even the most subtle forms of compulsive behavior while developing a more accepting stance toward intrusive thoughts. Understanding that "Pure O" is a misconception helps ensure that these crucial mental compulsions don't fly under the radar, allowing for more comprehensive and effective treatment approaches.