Abstract
BACKGROUND: Anhedonia, a diminished response to pleasurable stimuli extensively studied in mental disorders and chronic pain, has been reported as prevalent among patients with deep endometriosis. Anhedonia is considered a multifaceted transdiagnostic construct involving cognitive, affective, and behavioral processes related to the anticipation and experience of pleasure. In this study, we aim to expand on previous findings by exploring the presence of anhedonia in patients with ultrasound diagnosed (UD) endometriosis compared to a control group, and by examining how its anticipatory and consummatory components contribute to the loss of pleasure in this condition. METHODS: A total of 216 patients with UD endometriosis and 229 controls were recruited from a hospital gynecological service. Sociodemographic and clinical information was collected, and participants completed an online survey assessing anhedonia using a gold-standard measure, the Snaith-Hamilton Pleasure Scale (SHAPS). To assess anticipatory and consummatory components, the Temporal Experience of Pleasure Scale (TEPS) was administered, along with additional psychological measures of mood and anxiety. A moderated multiple regression model was performed to predict anhedonia scores based on TEPS subscales and diagnosis status. An additional model including anxiety, depression and dysmenorrhea was also conducted. Analyses were conducted using R version 4.4.3 and RStudio, with p-values set at < 0.05. RESULTS: Clinically pathological anhedonia was more prevalent in patients with UD endometriosis than in controls (31% vs. 15%, p < .001). UD endometriosis participants also reported greater menstrual pain, more chronic pain comorbidities, higher anxiety, and increased use of mental health services and hormonal treatments (all p < .05). In moderated regression analyses, UD endometriosis diagnosis, lower anticipatory pleasure, and lower consummatory pleasure significantly predicted anhedonia (p < .05), while depression was not predictive. A significant diagnosis × anticipatory pleasure interaction (p < .001) indicated stronger impairment among patients with UD endometriosis. This effect remained after adjusting for relevant covariates (anxiety, depression and dysmenorrhea). Depression was not predictive of anhedonia levels. CONCLUSIONS: Our findings confirm that patients with UD endometriosis consistently show deficits in deriving pleasure from everyday life experiences independently from depressive symptoms and directly influenced by anxiety and marginally dysmenorrhea. Notably, a specific impairment in anticipatory pleasure suggests a disruption in cognitive-affective processing associated with this chronic inflammatory condition. These results support the relevance for multidisciplinary care in UD endometriosis and highlight the transdisciplinary value of assessing anhedonia. Interventions targeting cognitive and affective processes may be essential for restoring health and improving quality of life in this patient population.