Abstract
Since the discovery of the P300 component, a large number of studies have been conducted with the aim to find abnormalities of this psychophysiological marker among the main psychiatric disorders. The first studies were very promising, but successive findings were rather controversial resulting in two main positions (the pros and the cons) as regard to the usefulness of P300 in clinical psychopathology. However, P300 studies provide interesting findings concerning information processing in psychopathology. Moreover, other Event-Related Potentials (ERPs), such as the Mismatch Negativity (MMN) and the Error-Related Negativity (ERN) are particularly interesting for the study of cognitive processes in psychopathology. In this review, the author will give an overview of the main findings of P300, MMN and ERN values in psychopathology from a clinical and a cognitive point of view. After a brief description of the rationale of ERPs, the findings in schizophrenia, depression, alcoholism, posttraumatic stress disorder, panic disorder, and obsessive-compulsive disorder will be sequentially reviewed. The diagnostic usefulness of P300 in psychopathology is limited, but could be increased if variables known to influence P300 amplitude or latency are controlled. Doubtless, grouping two or more different ERP components would greatly improve the usefulness of the clinical applications of brain potentials. On the other hand, a growing number of studies have provided evidence of the relevance of ERPs to investigate cognitive processes in psychopathology.