Differential response to deep brain stimulation in harm-avoidant vs. disgust subtypes of obsessive-compulsive disorder

Background: Deep brain stimulation (DBS) is a promising intervention for obsessive-compulsive disorder (OCD) refractory to conventional therapies. However, preoperative factors that reliably predict treatment response are not well established. Among patients with contamination OCD, some are concerned with substances potentially causing harm to themselves or others ("harm-avoidant"), while others are viscerally repulsed by them ("disgust"). Disgust-oriented OCD is associated with attenuated psychotherapy outcomes; relationship with DBS outcome has yet to be examined. Here, we compare clinical outcomes following DBS between harm-avoidant and disgust OCD subtypes. Methods: We conducted a retrospective cohort study of 14 contamination OCD patients (7 female, 7 male) undergoing DBS between 2019 and 2024 and categorized them as harm-avoidant or disgust based on clinical features. We assessed demographics and Yale-Brown Obsessive-Compulsive Scale-Second Edition (Y-BOCS-II) scores preoperatively and longitudinally. Results: Among 14 patients with contamination OCD, the harm-avoidant (n=10) and disgust (n=4) groups had similar demographic characteristics and baseline Y-BOCS-II scores (harm-avoidant: 40.4 +/- 4.2, disgust: 40.0 +/- 6.9, p=0.92, Welch's t-test). At the latest follow-up, harm-avoidant patients achieved significantly lower Y-BOCS-II scores (harm-avoidant: 13.8 +/- 11.1, disgust: 30.5 +/- 3.1; p=0.001, Welch's t-test). Nine of ten harm-avoidant patients achieved response status (>=35% score reduction) compared to only one of four disgust patients (p=0.04, Fisher's exact test). Conclusions: Disgust OCD patients experienced attenuated improvement following DBS compared to harm-avoidant OCD patients. If confirmed in larger cohorts, these findings could motivate preoperative phenotypic stratification, inform decision-making about DBS candidacy, and guide alternative therapeutic strategies for disgust patients.