The Chapman Anhedonia Study

Pleasure is a key concept insuring feeding, survival and procreation of a specie (Kringelbach, M.L.; Berridge 2010). Impairment in the experience of pleasure is known under the term “anhedonia” and represents an obstacle to the completion of these essential functions. The dominant definition of anhedonia has remained unaltered since 1869 (Ribot 1896) when it was first described as “the inability to experience pleasure”. This definition limits anhedonia to an impaired consummatory process (liking). More recently different conceptual understandings of anhedonia have emerged. Indeed the study of hedonia (the experience of pleasure) has been much more prolific than anhedonia and has revealed that reward processing consists of multiple sub-components
2012). Until now the assessment of anhedonia severity in MDD has mostly been performed through self-report questionnaires. Unfortunately, these instruments influenced by the original definition of anhedonia clearly emphasize the experience of pleasure (liking) while neglecting the other sub-components of reward (wanting, learning). This includes the Chapman Anhedonia Scale (Chapman et al. 1976), the Scale of Negative Symptoms (Andreasen 1989), the Fawcett–Clark Pleasure Scale (FCPS) (Fawcett et al. 1983) and the Snaith–Hamilton Pleasure Scale (SHAPS) (Snaith et al. 1995)). Another scale, the Mood-Anxiety Symptoms Questionnaire (MASQ) developed by Watson and Clark (Watson et al. 1995) includes items related to positive affect and interest assessing anhedonia to some degree. However, these items are not particularly specific and are usually not analyzed separately from the rest of the scale (Buckby et al.
Researchers are working on these issues as the development of news scales demonstrates. The temporal experience of pleasure scale (TEPS) (Gard et al. 2006)) is a clear attempt to dissociate the different sub-processes intervening in reward processing; in this case the consummatory and anticipatory aspect of hedonia, even though it is not clear yet whether or not the experience of pleasure during the anticipation of rewards and motivation toward reward are similar constructs. In the same way, the dimensional anhedonia rating scale (DARS) (Rizvi et al. 2015)) is a dynamic scale developed to assess desire, motivation, effort and consummatory pleasure. Finally depression specific instruments such as the Hamilton depression rating scale (HDRS) (HAMILTON 1967)) or the Beck depression Inventory (BDI-II) (Beck et al. 1996)) often assess anhedonia in a very limited proportion with the HDRS dedicating only one question to this symptom and the BDI only