[Anhedonia in depression]

Anhedonia, or markedly diminished interest or pleasure, is a hallmark symptom of major depression, schizophrenia, and other neuropsychiatric disorders. The term "anhedonia" was introduced by the French psychologist Ribot in 1896 to describe the counterpart to analgesia in his patients, for which "it was impossible to find the least pleasure". Over the last decades, the clinical definition of anhedonia has remained relatively unchanged, but recently, behavioral neurosciences have significantly changed our knowledge of reward-related processes. Now, the construct of anhedonia reflects deficits in hedonic capacity, and is closely linked to the processes of reward valuation, decision-making, anticipation, and motivation. The neural circuits underlying these reward-related mechanisms include essentially the ventral striatum and prefrontal cortical regions. Here, we review the clinical concepts, neural bases and psychopharmacological data related to the deficits of hedonia in depression. Understanding anhedonia will facilitate diagnosis and treatment management.