| Objective1. To investigate the neuro-cognitive characters (Event-related Potential P300, N400 and MMN) as well as the influence of antidepressant on Event-related Potentials in patients with major depressive disorders.2. To investigate the emotional cognitive characters (attentional bias towards emotional facial expressions) as well as the influence of antidepressant on attentional bias towards emotional information in patients with major depressive disorders.3. To investigate the social cognitive dysfunctional characters as well as the influence of antidepressant on social cognition in patients with major depressive disorders.4. To determine the relationship between the neuro-cognitive characters (Event-related Potential P300, N400 and MMN) and the emotional cognitive characters (attentional bias towards emotional facial expressions) as well as the social cognitive function by the the correlation analysis in patients with major depressive disorders, which might provide evidence for emotional cognition and social cognition measurement with Event-related Potentials.Methods1. According to the random number table and the admission order, twenty-five patients met the depressive disorders criteria of Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-Ⅳ) and rated scores of Hamilton Depression Scale(HAMD)(17 items) more than 24 scores were recruited as research group. Twenty-five age and sex-matched healthy controls with no personal or family histories of mental disorders were selected as normal control group.2. All participants were measured with Event-related potentials:1) Event-related potential P300 were evoked by "Oddball" paradigm; 2) Event-related potential N400 were evoked by ambiguous term of four word idioms paradigm; 3) Event-related potential MMN were evoked by "Oddball" paradigm of duration deviation and frequency deviation.Peak latencies and amplitudes of P300, N400 and MMN were used for analysis.4)A dot probe task of facial expression to measure cognitive bias of negative emotional information.3. All participants were measured with the Interpersonal Perception Task -15(ITP-15).4. Patients were treated with escitalopram for eight weeks.5. At baseline and after eight week treatments, patients were measured with HAMD, Hamilton Anxiety Scale(HAMA), P300, N400, MMN, ITP-15 and a dot probe task. Normal control group only measured with above tools and task once when were recruited as controls. Data were analyzed with paired-samples t-test, chi-square test, one-way ANOVA, repeated measures ANOVA and Pearson correlation analysis respectively.Results1 Comparisons of the HAMD scores at baseline and after 8 weeks of treatments with escitalopramAfter eight week treatments, the significant efficiency rate are 76% and total effective rate are 96%. Based on independent sample t-tests, significant differences in the HAMD scores between baseline (30.6±5.6) and after 8 weeks of escitalopram treatment (15.8±3.1) were observed (t=2.879; p=0.018). The 8 week treatment with escitalopram decreased the HAMD scores.2 Analysis of neuro-cognition data2.1 Event-related Potential P3002.1.1 Comparisons of the P300 latencies and amplitudes among at baseline and after 8 week treatment in research group and normal control groupThe P300 latencies (Pz, Cz, and Fz site) at baseline in research group were longer than that of after 8 week treatment in research group and normal control group, and P300 amplitudes (Pz, Cz, and Fz site) at baseline in research group were lower than that of after 8 week treatment in research group and normal control group(all p=0.000).2.1.2 Analysis of the correlation between HAMD scores and P300 latencies and amplitudes in research groupHAMD scores at baseline were positive correlated with P300 latencies (Pz, Cz, and Fz site)(r=0.417～0.456, p=0.038～0.042), and were negative correlated with P300 amplitudes(r=-0.409～-0.482, p=0.021～0.034) in research group.After eight week treatments, HAMD scores were positive correlated with P300 latencies (Pz, Cz, and Fz site)(r=0.510～0.559, p=0.039～0.045), and were negative correlated with P300 amplitudes(r=-0.530～-0.597, p=0.019～0.024).2.2 Event-related Potential N4002.2.1 Comparisons of the N400 latencies and amplitudes among at baseline and after 8 week treatment in research group and normal control groupThe N400 latencies (Pz, Cz, and Fz site) at baseline in research group were longer than that of after 8 week treatment in research group and normal control group, and N400 amplitudes (Pz, Cz, and Fz site) at baseline in research group were lower than that of after 8 week treatment in research group and normal control group(all p=0.000).2.2.2 Analysis of the correlation between HAMD scores and N400 latencies and amplitudes in research groupHAMD scores at baseline were positive correlated with N400 latencies (Pz, Cz, and Fz site)(r=0.498～0.558, p=0.038～0.049), and were negative correlated with P300 amplitudes(r=-0.529～0.683, p=0.031～0.039) in research group.After eight week treatments, HAMD scores were positive correlated with P300 latencies (Pz, Cz, and Fz site)(r=0.0587～0.623, p=0.028～0.042), and were negative correlated with P300 amplitudes(r=-0.593～-0.634, p=0.028～0.046).2.3 Event-related Potential MMN2.3.1 Comparisons of the MMN latencies and amplitudes among at baseline and after 8 week treatment in research group and normal control groupThere were no differences of the duration deviation and frequency deviation MMN latencies (Fz site) among at baseline and after 8 week treatment in research group and normal control group(p=0.109-0.836), and the duration deviation and frequency deviation MMN amplitudes (Fz site) at baseline in research group were lower than that of after 8 week treatment in research group and normal control group, (all p=0.000).2.3.2 Analysis of the correlation between HAMD scores and MMN latencies and amplitudes in research groupHAMD scores at baseline were negative correlated with the duration deviation and frequency deviation MMN latencies (Fz site)(r=-0.509,-0.531, p=0.016,0.020), and after eight week treatments, HAMD scores were negative correlated with the duration deviation and frequency deviation MMN amplitudes(r=-0.678,-0.594, p=0.015,0.018) in research group.3 Analysis of emotional cognition data3.1 Analysis of Dot-probe task of emotional facial expressions data3.1.1 Comparisons of the attentional bias scores at baseline between the patients and controlsSingle sample t-tests revealed that the attentional bias towards the unhappy faces was significantly greater than zero in the research group (t=2.791, p=0.009) but not in the normal control group (t= 1.660, p= 0.32).After eight week treatments,the attentional bias towards the unhappy faces was significantly greater than zero in the research group (t= 1.587, p= 0.45).3.1.2 Comparisons of the accuracy and RT of the research group at baseline and the normal control groupThere were significant differences between the accuracy in the neutral-neutral condition (97.88 ± 2.50) and those in the happy-neutral condition (96.61 ± 4.79, p= 0.022) and the unhappy-neutral condition (94.32 ± 3.60, p= 0.019). A 3×2 ANOVA with the emotional facial expression condition (unhappy-neutral and happy-neutral, neutral-neutral) as a within-subject factor and the group (patients at baseline and controls) as a between-subjects factor on the mean RT did not any reveal significant effects (F= 1.32, p= 0.130).3.1.3 Analysis of the correlation between HAMD scores and attentional bias towards the unhappy faces in research groupHAMD scores at baseline and after eight week treatments were positive correlated with the attentional bias towards the unhappy faces in research group(r=0.720,0.025, p=0.025,0.017).3.1.4 Analysis of the correlation between the attentional bias scores and latencies and amplitudes of P300, N400 and MMN in research groupThe attentional bias scores were positive correlated with P300 (Pz, Cz, and Fz site) latencies(r=0.223～0.570, p=0.014～0.042), and were negative correlated with amplitudes((r=-0.461～-0.501, p=0.028～0.038), and not correlated with N400 and MMN latencies and amplitudes in research group. After 8 week treatments, the attentional bias scores were positive correlated with P300 (Pz, Cz, and Fz site) latencies(r=0.464～0.530, p=0.021～0.047), and were negative correlated with amplitudes(r=-0.398～-0.443, p=0.026～0.039), and not correlated with N400 and MMN latencies and amplitudes in research group.4 Analysis of social cognition data4.1 Analysis of IPT-15 data4.1.1 Comparisons of the IPT-15 total scores and factors of the research group at baseline and the normal control groupIPT-15 total scores, kinship, intimacy, deception and competition factor scores in normal control group were higher than that of at baseline and after eight week treatments in the research group.There were no differences on IPT-15 total scores, kinship, intimacy, deception and competition factor scores between after eight week treatments in the research group and normal control group(p=0.137～0.140), although all above scores in normal control group were higher than that of at baseline in the research group.4.1.2 Analysis of the correlation between IPT-15 total scores and latencies and amplitudes of P300, N400 and MMN in research groupIPT-15 total scores were positive correlated with amplitudes of P300 and MMN (r=0.298～0.521, p=0.005～0.041), and not correlated with P300, N400 and MMN latencies and N400 amplitudes in research group.Conclusions1. Patients with major depressive disorders present neuro-cognitive dysfunction, including Identification, comparison, Judgment,Memory,Decisions,Expectation,The language cognitive processing and Pay attention to the unconscious, which reflected by abnormalities of P300, N400 and MMN.2. Patients with major depressive disorders present the emotional cognition dysfunction, which reflected by attentional bias towards the negative emotional information in the Dot probe task of emotional facial expressions..3. Patients with major depressive disorders present social cognitive dysfunctions, reflected by poor performance of IPT-15.4. There are correlation between neuro-cognition and emotional cognition as well as social cognition, and Event-related potentials might be bio-markers of emotional and social cognitive function for patients with major depressive disorders.5. Antidepressant can improve cognitive function in major depressive disorders. Abnormality of event-related potentials, the emotional cognition dysfunction (attentional bias towards the negative emotional information) and social cognitive dysfunctions is a state hallmark not a trait hallmark. |
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