Event-related potential correlates of depression, insight and negative symptoms in males with recent-onset psychosis

Objective: The neurobiology of clinical characteristics -in particular depression, insight and negative symptoms-in recent-onset psychosis (ROP) was studied using event-related potentials (ERPs). Methods: Twenty right-handed ROP men and 20 controls completed an auditory-oddball task. ROP men had minimum exposure to antipsychotic medication. N100, N200 and P300 were studied to ascertain the effects of (a) diagnosis (patients versus controls), and (b) clinical characteristics. Results: ROP men had significantly lower anterior N100, enhanced N200 at T3, and lower P300 at Pz than controls. Lower right-anterior N100 and enhanced right-anterior N200 amplitude explained 47.7% of negative symptoms. Left-central N100 amplitude explained 30.28% of negative symptoms. Lower left-posterior and higher right-posterior P300 amplitude explained 65.99% of total symptoms. Lower left-central N100, enhanced left-central N200 and depression explained 78.8% of impairments in insight and judgement. Impaired insight/judgement correlated positively with right-anterior N200 and was identified as the most significant co-efficient for depression. Conclusions: Disturbed selective-attention and executive function indexed by N100 and N200, respectively, are associated with poor insight and negative symptoms. A complex interaction exists between insight and depression. Significance: The current results demonstrate a biological basis of insight and depression and a complex interaction between the two, perhaps mediated by executive function, in early psychosis. (c) 2006 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.