Low-pleasure beliefs in patients with schizophrenia and individuals with social anhedonia.

Anhedonia in schizophrenia has been suggested to comprise a set of low-pleasure beliefs, defined as beliefs that certain things/activities were not pleasurable or that one does not feel pleasant generally. However, no instrument has been intentionally developed to specifically measure low-pleasure beliefs, and there is a paucity of empirical evidence for low-pleasure beliefs and their relationship with anhedonia in both patients with schizophrenia and individuals with high social anhedonia. We developed and validated the Beliefs About Pleasure Scale (BAPS) using non-clinical (Studies 1, 2 & 3), chronic schizophrenia (Study 2), and first episode schizophrenia (Study 3) samples. Across these studies, we examined psychometric properties of the BAPS, including temporal stability, internal consistency, factor structure, and convergent validity. The 22 BAPS items loaded onto 4 factors, namely the "Devaluation of Pleasure", the "Pleasurable Activity Expectancies", the "Negative Outcomes Expectancies", and the "Attention to Pleasure". The measure demonstrated good internal consistency and convergent validity in each sample. Moreover, both individual with schizophrenia and non-clinical participants with high social anhedonia scored higher on the BAPS than controls (Study 3), supporting construct validity. These findings provide preliminary evidence for the presence of low-pleasure beliefs in both clinical and subclinical groups and suggest that the BAPS has promising initial psychometric properties. The BAPS will be useful for exploring the cognitive component of anhedonia and provides a novel assessment for mechanism of change in psychosocial treatment studies.