Comparative change in P300 indices following antidepressant treatment in patients with major depressive disorder

CONTEXT: Cognitive disturbance is seen in patients with major depressive disorder (MDD). Event-related potential can assist in measuring the neurocognition, and P300 is the most commonly used noninvasive electrophysiological parameter for measuring cognition. AIMS: The aim of this study is to assess the baseline P300 parameters, Hamilton Rating Scale for Depression (HAM-D), and Montgomery–Asberg Depression Rating Scale (MADRS) scores and compare them with their levels after 3 months of antidepressant therapy. SETTINGS AND DESIGN: a longitudinal study was done on total 24 diagnosed cases of major depression who underwent P300, HAM-D, and MADRS assessment in the gap of 3 months before and after starting antidepressant therapy. SUBJECTS AND METHODS: Newly diagnosed cases of MDD patients were assessed using HAM-D and MADRS for severity rating. P300 assessment was also carried out with auditory oddball paradigm using Nihon Kohden NCV-SMG-EP system. The assessments were repeated after 3 months of antidepressant treatment. STATISTICAL ANALYSIS USED: The Wilcoxon test was used to compare mean values of P300 parameters, HAM-D, and MADRS score. Spearman correlation analysis was done to study the association between various parameters of P300 and HAM-D and MADRS score before and after treatment of 3 months of antidepressant therapy. RESULTS: Significant difference is shown in various parameters P300 except for A11-P300 amplitude and A31-P300 amplitude. A significant difference was shown in HAM-D and MADRS scores. No significant correlation was seen between other P300 parameters and HAM-D and MADRS scale before as well as after antidepressant therapy. CONCLUSIONS: P300 may be used as an index to evaluate the response to antidepressant treatment in patients with MDD.