Efficacy of Ketamine as an Adjuvant to Antidepressants in the Treatment of Depression

Abstract

Introduction: Depression is the second leading cause of morbidity worldwide. Currently, available antidepressants mostly target the monoamine system. The onset of action and response rates for these antidepressants are varied. Ketamine, an N-methyl-Daspartate (NMDA) receptor antagonist has shown rapid onset of action in the treatment of depression. The available literature about intravenous (i.v.) ketamine as an adjuvant to oral antidepressants is limited. Aim: To study if ketamine is beneficial as an adjuvant to antidepressants in the treatment of depression. Materials and Methods: This study was a prospective interventional study conducted at JSS Medical College and Hospital, Mysuru, Karnataka, India, between January 2019 to January 2021. Total 60 patients diagnosed with depression and receiving 20 mg per day of the Selective Serotonin Reuptake Inhibitor (SSRI) escitalopram were recruited. The patients were divided into two groups of 30. Group I was continued only on the oral antidepressant antidepressant and the group II in addition to the oral antidepressant received 3 doses of i.v. infusion of ketamine hydrochloride, on alternate days. All the patients were assessed using the Montgomery-Asberg Depression Rating Scale (MADRS) and the Beck Scale for Suicidal Ideation (BSSI) at baseline and after 14 days. Statistical measures like Cramer’s V, Independent samples t-test (to match both groups for age) and repeated measure Analysis of Variance (ANOVA) was employed and data collected were analysed through the IBM Statistical Package for the Social Sciences (SPSS) statistics for windows, version 20.0. Results: The mean age of the sample population was 37.883±8.128 years. There was statistically significant improvement in depressive symptoms in group II when compared to group I. There was a decrease in mean MADRS scores by 6.07 in Group I and by 8.10 in Group II (p-value=0.011). The improvement was statistically significant in four items on the MADRS scale, namely, reported sadness (p-value=0.015), inner tension (p-value=0.021), pessimistic thoughts (p-value=0.00034) and suicidal thoughts (p-value=0.001), as well as the total MADRS score (p-value=0.011). The mean change in BSSI scores from baseline to final reading improved in both the groups (p-value=0.740). Conclusion: Intravenous ketamine as an adjuvant to oral antidepressant medications, showed greater and more rapid improvement than that seen with oral antidepressants alone. It can be considered as an effective adjuvant to other antidepressants and future studies are required to establish this.

Keywords

• major depressive disorder
• mood disorder
• suicide