Evaluation of anhedonia with the Snaith-Hamilton Pleasure Scale (SHAPS) in adult outpatients with major depressive disorder.

Anhedonia or inability to experience pleasure not only is a core symptom of major depressive disorder (MDD), but also is identified as an important component of the positive valence system in the NIMH Research Domain Criteria. The Snaith-Hamilton Pleasure Scale (SHAPS) has been developed for the assessment of hedonic experience or positive valence, but has not been well-studied in depressed outpatient populations. The current study examined the reliability and validity of the SHAPS using a sample of adult outpatients with treatment resistant MDD. Data for the current study were obtained from 122 adult outpatients with a diagnosis of MDD and non-response to adequate treatment with an SSRI and who participated in Project TReatment with Exercise Augmentation for Depression (TREAD). A Principal Components Analysis was used to define the dimensionality of the SHAPS. Convergent and discriminant validity were evaluated via correlations of the SHAPS total score with "gold standard" measures of depression severity and quality of life. The SHAPS was found to have high internal consistency (Cronbach's coefficient α = .82). A Principal Components Analysis suggests that the SHAPS is mainly "unidimensional" and limited to hedonic experience among adult outpatients with MDD. Convergent and discriminant validity were assessed by examining the Spearman rank-order correlation coefficient between the SHAPS total score and the HRSD17 (rs = 0.22, p < .03), IDS-C30 (rs = 0.26, p < .01), IDS-SR30 (rs = 0.23, p < .02), QIDS-C16 (rs = 0.22, p < .03), QIDS-SR16 (rs = 0.17, p < .10), QLES-Q (rs = -0.32, p < .002), and the pleasure/enjoyment item (sub-item 21) of the IDS-C (rs = 0.44, p < .0001) and IDS-SR (rs = 0.38, p < .0002). The self-administered SHAPS showed modest sensitivity (76%) and specificity (54%) with the self-administered pleasure/enjoyment single item (sub-item 21) of IDS-SR30. The current study shows that the SHAPS is a reliable and valid instrument to assess hedonic experience or positive valence in adult outpatients with MDD and provides a broader assessment of this important domain.