The role of mnemonic discrimination in symptom severity and treatment response of obsessive-compulsive disorder

Mnemonic discrimination, the ability to differentiate novel stimuli from highly similar past ones, has been evidenced as a compelling factor for fear overgeneralization in anxiety disorders. However, very limited research has examined mnemonic discrimination in obsessive-compulsive disorder (OCD). The current study provided an initial examination of the relationship between mnemonic discrimination to OCD symptoms and treatment response. Patients (N = 48) in an intensive partial hospital/residential treatment program for OCD completed the Mnemonic Similarity Task at admission and discharge, along with self-report measures of OCD severity, trait worry, intolerance of uncertainty, and threat estimation. Results showed no significant relationship between mnemonic discrimination and baseline OCD symptom severity. Over the course of treatment, mnemonic discrimination did not change significantly, nor was it associated with OCD symptom reduction. Notably, however, there was a significant interaction between poor mnemonic discrimination and high trait worry to predict more severe OCD symptoms at baseline. Findings suggested that while mnemonic discrimination alone might not be a risk factor for OCD severity or impact treatment response, it could be a potential transdiagnostic risk factor that exacerbates internalizing symptoms when co-present with other cognitive vulnerabilities. Future studies should continue investigating the mechanistic link behind these relationships in larger, more representative samples.