Efficacy of Ketamine-Assisted Psychotherapy in Treatment-Resistant Depression - a case series

Abstract

Ketamine-assisted psychotherapy (KAP) has emerged as a potential approach for patients with Treatment-Resistant Depression (TRD). However, several questions regarding the optimal implementation protocol and efficacy have yet to be thoroughly studied. We conducted a case series involving 31 patients diagnosed with TRD. Our KAP protocol, supervised by a physician, consisted of two preparation sessions, followed by a minimum of four weekly sessions of intravenous ketamine administration, starting with an initial dose of 0.5 mg/kg. Each ketamine session was followed by an integration psychotherapy session the next day. A follow-up reassessment was held one month after the final intervention to evaluate whether the antidepressant benefits were sustained. Depressive and anxiety symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9) and the Generalized Anxiety Disorder Assessment (GAD-7), respectively. The evaluations occurred during the second preparation session, the last integration session, and the reassessment consultation. There was significant improvement (p < 0.05) in PHQ-9 scores following the KAP intervention and at the reassessment evaluation, with mean scores decreasing from 17.68 (SD = 0.81, 95% CI = 16.03 to 19.32) at baseline to 6.87 (SD = 0.86, 95% CI = 5.11 to 8.63) in the last integration session, and to 7.71 (SD = 1.19, 95% CI = 5.24 to 10.17) at reassessment. Importantly, 38.70% of patients remitted from depression immediately after KAP, with an increase to 41.70% at reassessment. This study suggests psychotherapy may sustain ketamine's antidepressant effects, but further research is needed to assess the long-term impact and identify the most effective psychotherapy for patients with TRD.