RESUMEN
Objective • To explore the relationship between θ oscillation of auditory event-related potential P300 and clinical symptoms in the patients with clinical high risk (CHR) of psychosis or first episode schizophrenia (FES). Methods • A total of 18 patients with CHR of psychosis (CHR group), 18 patients with FES (FES group) and 19 healthy controls (control group) were recruited to complete the standard auditory Oddball paradigm as well as electroencephalogram (EEG) recording with 64-channel EEG cap. Fz, Cz and Pz electrodes were selected to compare the amplitudes and peak latent periods among the three groups, and time-frequency analysis of the θ oscillation in P300 was performed. Results • There was significant difference in the amplitudes of P300 among the three groups (P=0.004). The amplitudes of P300 in FES group (P=0.001) and CHR group (P=0.026) were both significantly lower than that of control group. There was no difference between CHR group and FES group in P300 amplitude (P>0.05). θ Oscillation induced power was significantly different among the three groups (P=0.022). The induced power value of FES group was significantly lower than that of control group (P=0.008); and it was marginally lower in CHR group as compared to that of control group (P=0.054). There was no difference between CHR group and FES group (P>0.05). There was trending difference in θ oscillation evoked power among the three groups (P=0.054). The correlation analysis showed that the total and subscale scores of Positive and Negative Syndrome Scale in FES group were significantly correlated with the amplitudes of P300 at Cz and Pz electrodes (P<0.05). Conclusion • There are significant abnormalities in the amplitude of auditory P300 and θ oscillation of P300 in both CHR and FES patients; however, the change in CHR patients is less severe than that of FES patients. The impaired θ oscillation of P300 in CHR patients is limited to induced power, but evoked power is not impaired.
RESUMEN
Objective • To explore and analyze the characteristics of nicotinic acid skin sensitivity in clinical high risk (CHR) population of psychosis. Methods • One hundred and five patients with CHR of psychosis (CHR group) and fifty-one patients with first episode schizophrenia (FES) (FES group) in Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine from Jun. 2016 to Jun. 2018, and fifty-four healthy controls (HC group) were included. The patients of CHR group met the criteria of prodromal syndromes, and the patients of FES group met the diagnostic criteria of Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition). The patients of HC group were matched with CHR group in age and gender. The niacin skin flush of the three groups were detected. The niacin skin flush scores of the three groups were compared by single factor repeated measurement variance analysis (MANOVA). The niacin flush negative rates of the three groups were compared by Chi-square test. Results • Compared with HC group, the niacin skin flush of CHR group and FES group reduced at different concentrations and time points. MANOVA showed a significant main group effect of niacin skin flush (F=1.746, P=0.009). There were no significant group × concentration interaction (F=1.628, P=0.138) and group × time interaction (F=0.851, P=0.531). Compared with HC group, the niacin total flush scores of CHR group were lower (t=-2.697, P=0.008). The significant differences of the proportion of patients with negative niacin reaction among the three groups were found for the concentration of 0.1 mol/L at 5 min (χ2=16.709, P=0.000) and 0.001 mol/L at 20 min (χ2=6.380, P=0.041). Conclusion • The reduction of the niacin skin flush can occur not only in the patients with schizophrenia but also in the CHR of psychosis in the precursor phase. Niacin skin flush may be an early biological marker of schizophrenia.