Cocaine Use Disorder: Anhedonia and Emotional Flattening

Anhedonia, the reduced capacity to experience or pursue pleasure, is common among individuals with cocaine use disorder (CUD) and may contribute to poor treatment outcomes. This blunted emotional experience may extend beyond diminished positive affect to include reduced sensitivity to negative emotions, suggesting a broader emotional flattening. This narrowing of the emotional spectrum has been noted in other clinical populations and, if also present in individuals with CUD, may offer a key target for more effective treatment strategies. We hypothesized that individuals with greater anhedonia would rate images more neutrally, regardless of valence or arousal, and that this emotional flattening would extend to physiological responses, including heart rate reactivity and facial muscle activity (corrugator EMG). To test this, 53 participants (83% male) diagnosed with moderate-to-severe CUD based on DSM-5 criteria completed the Snaith-Hamilton Pleasure Scale (SHAPS), a validated 4-point measure of anhedonia, and the Emotional Picture Rating Task (EPRT). In the EPRT, participants viewed 36 emotional images (positive, neutral, and negative) from the Nencki Affective Picture System. After each 6-second image presentation, they rated the valence (-4 to +4) and arousal (0 to 9), while heart rate and corrugator EMG were continuously recorded. Mixed-effects models revealed a significant interaction between picture type and anhedonia on valence ratings, indicating that higher anhedonia was associated with reduced differentiation in valence. A quadratic pattern emerged for arousal ratings, but anhedonia did not significantly moderate this effect. Physiologically, anhedonia did not significantly influence heart rate deceleration or acceleration, but also typical emotional heart rate patterns were not observed in the overall sample, possibly due to cocaine-related cardiac disruptions. Corrugator activity varied by picture type as expected but did not differ by anhedonia level. These findings suggest that while anhedonia in CUD is associated with subjective emotional flattening, this is not mirrored in physiological measures. These findings highlights the potential value of interventions that increase emotional sensitivity across the full emotional spectrum. Treatments such as Acceptance and Commitment Therapy, Radically Open DBT, and interoceptive-based approaches may be particularly effective for addressing this pattern in individuals with CUD.