Effect of hedonic tone on event-related potential measures of cognitive processing.

Anhedonia, the inability to experience pleasure, is a core feature of several psychiatric disorders such as schizophrenia, depression, and substance dependence. Furthermore, it has been suggested that anhedonia is an important predictor of schizophrenia. Anhedonia has been associated with information-processing deficits, especially attentional deficits, which may predispose for schizophrenia. In the present study, event-related potentials (ERPs) were used to examine the influence of hedonic tone on information-processing characteristics in a sample of healthy individuals. Thirty-five healthy subjects were divided into two groups based on their scores on the Snaith-Hamilton Pleasure Scale (SHAPS). Cognitive functions were measured during an active visual oddball paradigm. It was found that both early, middle and late ERP components of subjects with low levels of hedonic tone were attenuated compared with ERPs of subjects with high levels of hedonic tone. These findings suggest that decreased hedonic tone is associated with reductions in both automatic and effortful cognitive processing of relevant stimuli. Consequences of these findings for the vulnerability to psychopathology are discussed.