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

Abstract

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