A follow-up study on features of sensory gating P50 in treatment-resistant depression patients / 中华医学杂志(英文版)

ABSTRACT

<p><b>BACKGROUND</b>Depressive disorder is a well-known chronic, recurrent and disabling mental disease with high direct and indirect costs to society in both western and eastern cultures. Approximately 40% of depressed patients show only partial or no response to initial or even multiple antidepressant medications and are usually called treatment-resistant depression (TRD) patients. The present work was to measure the features of sensory gating (SG) P50 in TRD patients with the intent of understanding the characteristics of this disease.</p><p><b>METHODS</b>In 50 TRD patients, 39 non-treatment-resistant depression (NTRD) patients and 51 healthy controls (HC), auditory evoked potential P50 was measured using the conditioning/testing paradigm presented with auditory double clicks stimuli, and 36 TRD patients had repeated measurements after an 8-week venlafaxine treatment course.</p><p><b>RESULTS</b>All the depressive disorder patients, including the TRD and NTRD groups, showed an increased testing stimulus wave (S2-P50) amplitude compared to controls (P < 0.01 and P < 0.05), but there was no significant difference between the TRD and NTRD groups (P > 0.05). There were significant differences in the ratio of testing stimulus (S2) and conditioning stimulus (S1) (S2/S1) and in the value of 100 x (1 - S2/S1) among the three groups. Compared to the baseline, TRD patients had no significant changes of features and different expression of P50 after acute treatment (P > 0.05). Meanwhile, a statistically significant positive correlation of S2/S1 with the scores of the 17-item Hamilton Rating Scale for Depression (HAMD-17) (P < 0.01), and a significantly negative correlation of S1 - S2, 100 x (1 - S2/S1) with the scores of HAMD-17 (P < 0.01) were observed in the TRD patients' baseline measurement, but there was no correlation after venlafaxine treatment (P > 0.05).</p><p><b>CONCLUSIONS</b>Both the TRD and NTRD patients had obvious SG deficits, with a more severe deficit in TRD patients. Although, with a correlated relationship to the severity of depressive symptoms, SG P50 deficit might be suggested as a trait marker for TRD, and a combination of S2/S1 ratio, S1 - S2 and 100 x (1 - S2/S1), was recommended for electrophysiological measurement in TRD patients.</p>