An ERPs Study In Depression Before And After Treatment With SSRIs

Objective The target is to explore the event-related potentials P300 is in phenotype or not in depression, and to analysis the relation between it and cognitive function,life events.Methods 99 cases of patients who were diagnosed by DSM-Ⅳwith first onset of depression as a case group was collected.100 cases matched with patients in these aspects—age, gender, years of schooling—were selected as control group. The former was given citalopram to cure. The symptoms, cognitive and the event related-potentials (ERPs) were obtained at the time before treatment and on 6 weeks,12 weeks,24 weeks after treatment. HAMD-24 (Hamilton Rating Scales of Depression), WCST(Wisonsin card sorting test), LES(Life Event Scale),LES(Life Event Scale) were used to evaluate depressive symptoms, cognitive, life events,especially.P300 of the two groups was detected by the Nicolet brain instrument.SPSS13.0 was applied:t test was used to analysis the difference of indicators among groups; correlation was used to analysis the relation between scores of scales and P300; repeated measure analysis of variance was used to analysis the longitudinal changes of symptoms and P300.Results1. Results of the comparison of P300 between case and control group before treatmentCompared with normal control group, cases at Cz had longer latency of N2,P3,P2-N2 (P <0.001-0.01), and shorter latency of N2-P3((P<0.001),and had lower amplitude of N2, P3, N2-P3 (P<0.001-0.05), and higher amplitude of P2-N2 (P<0.01).2. Results of the longitudinal changes of symptoms and P300(1).The longitudinal changes of HAMD-24The results of repeated analysis of variance:in addition to diurnal variation, the total scores of 17, and 7 factors during treatment had no significant conclusions, P<0.001. The cores were decreased significantly after treatment, and most sharply on the 6th week (P <0.001).Paired-samples t test showed the scores reduced obviously before and after treatment for 6 weekst(P<0.001).(2).The longitudinal changes of P300The results of repeated analysis of variance: a downward trend was found in N2,P3,P2-N2 latency and a upward one in N2-P3 latency in the four periods; A upward trend could also be found in P3,N2-P3 amplitude. But there were no statistically mean difference(P>0.05).The results of paired-samples t test:①P3,N2-P3 amplitude in case group is higher after treatment for 6 weeks than before treatment, the difference is significant(P<0.001);②no significant results were found in P300 latency or amplitude between the 62 cases of depression after treatment for 24 weeks and 65 cases were selected from the 100 cases in control group, which was matched in age, gender, years of schooling with the former (P>0.05).3,Results of the relation between P300 and the symptoms(1).Before treatmentThere was a negative correlation between retardation and P2-N2 amplitude(r=-0.272, P< 0.05);and positive relation between it and P2-N2 latency (r= 0.245, P<0.05), N2-P3 amplitude (r= 0.245,P<0.05),respectively. P2 latencies and the total time, the error of time thinking negatively correlated; and the numbers of the completion for the first classification required to be answered, the percentage of conceptual level positively correlated. P2-N2 latency and the numbers of the completion for the first classification required to be answered P3 amplitude and correct thinking time also negatively correlated.N2-P3 amplitude and corrects, correct thinking time, the numbers of sustained response negatively correlated; and was positively correlated with the wrong choice rate.P<0.01-0.05.No significant results between P300 and the scores of the positive, negative and total of LES could be found.(2).After treatmentAfter treatment for 24 weeks, no relevant results could be found in retardation of HAMD (P> 0.05) in depression.Conclusion1.P300 latency and amplitude tend to be partly recovered after the acute phase of treatment in patients with depression, but the variation after the long-term therapy is not yet clear, whether P300 is in phenotype or not is yet to be further studied.2.Relation between inter-peak and retardation can be found, which suggests there are relation between retardation and complex cognitive activities in cerebral. After treatment for 24 weeks, no relevant results could be found in retardation of HAMD-24, which suggests that patients' cognitive function of depression after treatment with citalopram can be partly recovered.