The clinical use of electroencephalography in a general psychiatric setting

Electroencephalography (EEG) is used in psychiatric services, however, clinical guidelines do not clearly state when EEG is indicated, and its diagnostic value in psychiatric settings is unclear. We aimed to characterize the clinical use and diagnostic consequences of EEG in a general psychiatric setting to evaluate and optimize its use. We performed a quality development project at the psychiatric services of the Central Denmark Region. We identified patients referred for EEG examination from psychiatric services between 1 September 2017 and 1 September 2022. We extracted data from electronic health records on patient characteristics, indications, EEG results, and treatment consequences and analyzed risk factors for abnormal EEGs. Among 57,031 persons seen in the psychiatric services in the study period, 219 (0.4%) were referred for EEG examination. Psychosis (<i>n</i> = 70, 32%) was the most common symptom and suspicion of epilepsy (<i>n</i> = 129, 59%) was the most common clinical suspicion leading to referral. Of the 219 patients, 53 (24%) had an abnormal EEG result including 17 (7.8%) with epileptiform changes. Abnormal EEGs led to treatment alterations in six patients (3%). Age, prior epilepsy, use of antiseizure medication, use of clozapine, and convulsions were associated with epileptiform changes in the EEG. EEG is rarely used in psychiatric settings and seldom has treatment consequences. However, in specific clinical settings, the EEG result leads to an alteration of clinical management and the findings, therefore, call for refinement of clinical guidelines to optimize the use of EEG.