Frontal delta power associated with negative symptoms in ultra-high risk individuals who transitioned to psychosis

Abstract

It has recently been shown that treatment with long-chain omega-3 polyunsaturated fatty acids (PUFAs) could decrease the rate of transition to psychosis, and improve psychiatric symptoms and global functioning in people at ultra-high risk (UHR) for psychosis. Previous studies have suggested that resting state brain activity measured with electroencephalography (EEG) may represent an objective biomarker of changes in neural function associated with supplementation with omega-3 PUFAs. It has also been proposed that although resting state EEG cannot, by itself, predict transition to psychosis in UHR individuals, the combination of resting state EEG with negative symptoms may be a valid predictor of transition. The present study investigated whether treatment with omega-3 PUFAs influenced resting state EEG in UHR participants, and whether or not the association of the participants' resting state EEG with their levels of negative symptoms was dependent on their transition status. The brain activity of 73 UHR participants was recorded in the context of a randomized, placebo-controlled trial of the effects of supplementation with omega-3 PUFAs. The UHR participants who subsequently transitioned to psychosis (UHR+) did not differ from those who did not transition (UHR-) in terms of resting state EEG power in any frequency band. However, negative symptom scores were associated with increased delta activity in the frontal region of the UHR+ participants, but not in the UHR- participants. Treatment with omega-3 PUFAs did not induce changes in resting state EEG in either group. The results suggest that decreased frontal delta activity, in combination with high levels of negative symptoms, may be a risk factor for subsequent transition to psychosis in UHR individuals.