EEG abnormalities and two year outcome in first episode psychosis

Objective: This study examines the relationship of EEG to 2 year symptomatic outcome, duration of illness and untreated psychosis and gender. Method: A total of 122 patients presenting for treatment of first episode psychosis had their baseline EEG classified by modified Mayo Clinic system criteria as normal, essentially normal or dysrhythmia. Positive and negative symptoms of psychoses were rated on entry and after 2 years of treatment. The socio-demographic variables and duration of illness and of untreated psychosis were also recorded. Results: Patients with a normal EEG showed significantly more reduction in both positive and negative symptoms of psychoses over 2 years and were more likely to be in 'remission' as compared with the essentially normal or dysrhythmia group. The dysrhythmic group had significantly higher duration of illness than either the normal or essentially normal groups. There were no gender differences in the distribution of EEGs. Conclusion: An abnormal EEG in patients with first episode psychosis is associated with a poorer prognosis and a longer duration of untreated illness.