The assessment of anhedonia in clinical and non-clinical populations: further validation of the Snaith-Hamilton Pleasure Scale (SHAPS).

BACKGROUND: Anhedonia, the inability to experience pleasure, is a major endophenotype of depression. In addition to this, it is an important clinical feature of schizophrenia and substance abuse disorders. Valid instruments to measure anhedonia are sparse.
METHODS: In the present study, a short, 14-item instrument, the Snaith-Hamilton Pleasure Scale (SHAPS) to measure anhedonia in normal and clinical samples was further validated. Various aspects of the reliability and validity of the SHAPS that have not been addressed before, were examined in three separate studies. First, we assessed the internal consistency, convergent and discriminative validity of the SHAPS in a non-clinical sample. Second, the test-retest reliability of the SHAPS was investigated in another sample. In the third study, the internal consistency, convergent and discriminative validity of the SHAPS was tested by administering the scale in three clinical samples of psychiatric inpatients.
RESULTS: The SHAPS was found to be highly reliable in terms of internal consistency and test-retest stability. Further, the SHAPS correlated in a theoretically meaningful way with other measures of affect and personality. Patients with a depression, psychosis or substance dependence scored significantly higher on the SHAPS than non-patient controls. Patients with a depression displayed the highest SHAPS-score. LIMITATIONS: The absence of structured assessment data to validate the clinical diagnoses.
CONCLUSIONS: The current study shows that the SHAPS is a reliable and valid questionnaire to assess hedonic tone in patient and non-patient populations. Because it is a brief scale it seems to be a very useful instrument for measuring anhedonia in clinical and research settings.