Anhedonia as an indicator of genetic vulnerability to schizophrenia

The symptom of anhedonia has been central to causal theories of schizophrenia put forth by Rado and Meehl. Yet, the significance of anhedonia to the etiology of schizophrenia remains unclear. Anhedonia is regarded as a core symptom of schizophrenia and has been repeatedly observed in biological relatives of people with the disorder. This chapter summarizes findings for trait anhedonia being an indicator of genetic vulnerability for schizophrenia. Relevant studies of twins and families affected by schizophrenia, of the general population, and select animal models of the disorder, are reviewed. Evidence suggests that trait anhedonia may conform to the criteria for an endophenotype as defined by Gottesman and Gould (2003). Nonetheless, concerns about diagnostic specificity and variation in findings across self-report and experiment-based measurement warrant further investigation, to more fully understand how the symptom reflects genetic liability for schizophrenia.