Altered spontaneous brain activity associated with intolerance of uncertainty and not-just-right experiences in...

Obsessive-compulsive disorder (OCD) is clinically heterogeneous, and traditional threat-based models do not fully explain this diversity. Intolerance of uncertainty (IU) and not-just-right experiences (NJREs) have emerged as clinically relevant features of OCD, but their associations with spontaneous brain activity remain unclear.

Fifty-seven patients with OCD and 38 healthy controls (HCs) underwent resting-state functional magnetic resonance imaging. Regional spontaneous activity was assessed using the amplitude of low-frequency fluctuations (ALFF). Clinical measures included the Intolerance of Uncertainty Scale, the Not-Just-Right Experiences Questionnaire-Revised, the Yale-Brown Obsessive Compulsive Scale, and the State Anxiety Inventory. Group differences in ALFF were examined, and partial correlations were performed within the OCD group after controlling for age, sex, education, mean framewise displacement, state anxiety, and medication status.

Compared with HCs, patients with OCD showed increased ALFF in the bilateral orbital middle frontal gyrus and decreased ALFF in the left precuneus and right superior parietal gyrus. They also exhibited significantly higher IU scores. Within the OCD group, greater IU was associated with more severe NJREs and obsessive-compulsive symptoms (both Bonferroni-corrected p < 0.0125). Although IU was not associated with regional ALFF, greater NJRE severity was associated with both higher symptom severity and increased ALFF in the right orbital middle frontal gyrus (r = 0.380, p = 0.006).

OCD is characterized by altered frontoparietal spontaneous activity and elevated IU. The observed associations among IU, NJREs, symptom severity, and orbitofrontal ALFF suggest that uncertainty-related vulnerability, incompleteness-related experiences, and altered intrinsic brain activity are interconnected clinical features of OCD.