Anhedonia and Reward System: Psychobiology, Evaluation, and Clinical Features

Abstract

Anhedonia can be defined as a condition in which the hedonic capacity is totally or partially lost. From a psychobiological perspective, several researchers proposed that anhedonia has a putative neural substrate, the dopaminergic mesolimbic and mesocortical reward circuit, which involves the ventral tegmental area, the ventral striatum and part of the prefrontal cortex. Anhedonia is, besides depressed mood, one of the two core symptoms of depression; furthermore it is one of the most important negative symptom in schizophrenia. Anhedonia is also present in substance use disorders as part of the abstinence symptomatology, and interrelations between hedonic capability, craving and protracted withdrawal have been found, particularly in opiate-dependent subjects. Although anhedonia is regarded as an important symptom in psychopathology, so far it has received relatively little attention. In general, two main approaches have been utilized to investigate and assess anhedonia or hedonic capacity: laboratory-based measures and questionnaires. Among measurement scales, the most commonly used are the Snaith-Hamilton Pleasure Scale (SHAPS), the Fawcett-Clark Pleasure Scale (FCPS), and the Revised Chapman Physical Anhedonia Scale (CPAS). Nevertheless, other measurement scales, particularly used within broader psychopathological dimensions, are the Anhedonia-Asociality subscale (SANSanh) of the Scale for the Assessment of Negative Symptoms (SANS) and the Bech-Rafaelsen Melancholia Scale (BRMS). In this paper we analyze these different scales, individuating their strengths and limits and their current clinical applications.