Event-related potential (ERP) measures of error processing as biomarkers of externalizing disorders: A narrative review

Previous studies have shown that electrophysiological measures of error processing are affected in patients at risk or diagnosed with internalizing disorders, hence, suggesting that error processing could be a suitable biomarker for internalizing disorders. In this narrative review, we will evaluate studies that address the role of event-related potential (ERP) measures of error-processing in externalizing disorders and discuss to what extend these can be considered a biomarker for externalizing disorders. Currently, there is evidence for the notion that electrophysiological indices of error processing such as the error-related negativity (ERN) and error positivity (Pe) are reduced in individuals with substance use disorders, attention-deficit/hyperactivity disorder, and in forensic populations. However, it remains unclear whether this is also the case for other understudied disorders such as behavioral addiction. Furthermore, to fully understand how these deficits affect day to day behavior, we encourage research to focus on testing current theories and hypotheses of ERN and Pe. In addition, we argue that within an externalizing disorder, individual differences in error processing deficits may be related to prognosis and gender of the patient, methodological issues and presence of comorbidity. Next, we review studies that have related treatment trajectories with ERP measures of error processing, and we discuss the prospect of improving error processing as a treatment option. We conclude that ERP measures of error processing are candidate biomarkers for externalizing disorders, albeit we strongly urge researchers to continue looking into the predictive value of these measures in the etiology and treatment outcome through multi-method and longitudinal designs