We aimed to determine whether individuals with obsessive-compulsive disorder (OCD) and demographically matched healthy individuals can be clustered into distinct clinical subtypes based on dimensional measures of their self-reported compulsivity (OBQ–44 and IUS–12) and impulsivity (UPPS–P).

Participants (n=217) were 103 patients with a clinical diagnosis of OCD; 79 individuals from the community who were “OCD-likely” according to self-report (Obsessive-Compulsive Inventory–Revised scores equal or greater than 21); and 35 healthy controls. All data were collected between 2013 and 2015 using self-report measures that assessed different aspects of compulsivity and impulsivity. Principal component analysis revealed two components broadly representing an individual's level of compulsivity and impulsivity. Unsupervised clustering grouped participants into four subgroups, each representing one part of an orthogonal compulsive-impulsive phenotype.

Clustering converged to yield four subgroups: one group low on both compulsivity and impulsivity, comprised mostly of healthy controls and demonstrating the lowest OCD symptom severity; two groups showing roughly equal clinical severity, but with opposing drivers (i.e., high compulsivity and low impulsivity, and vice versa); and a final group high on both compulsivity and impulsivity and recording the highest clinical severity. Notably, the largest cluster of individuals with OCD was characterized by high impulsivity and low compulsivity. Our results suggest that both impulsivity and compulsivity mediate obsessive-compulsive symptomatology.

Individuals with OCD can be clustered into distinct subtypes based on measures of compulsivity and impulsivity, with the latter being found to be one of the more defining characteristics of the disorder. These dimensions may serve as viable and novel treatment targets.

To determine the rates and associated illness characteristics of obsessive-compulsive disorder (OCD) patients who describe their symptoms as either rewarding or habitual.

Seventy-three treatment-seeking OCD patients had their dominant compulsive behavior assessed with a structured interview (the Temporal Impulsive-Compulsive Scale–Revised) to track the progression of rewarding (ie, gain in positive affect), aversive (ie, decrease in negative affect), and neutral (or non-affective) states and a self-report scale (the Self-Report Habit Index) to evaluate their habitual features. Additional measures included structured diagnostic interviews for axis I and II disorders, measures of OCD symptoms severity, and a battery of instruments to comprehensively assess relevant aspects of sensitivity to reward and fear.

Almost half (49%) of our OCD patients (particularly washers) endorsed that they anticipated obtaining a reward (ie, positive affect) from the enactment of their dominant compulsive behavior. Washers stood out in that their positive affects during and after compulsive behaviors were highly (and positively) correlated with duration of illness. In contrast, habit strength did not differ between washers, checkers, and arrangers, although it also correlated with duration of illness among checkers. Furthermore, the severity of OCD and comorbidity with impulse control disorders predicted up to 35% of the variance in the habit strength of OCD behaviors.

Compulsive washing may be more clearly characterized by problems in reward processing. In contrast, duration of checking, severity of OCD, and comorbidity with impulse control disorders shape compulsive behaviors by imparting them with habitual tendencies.