PURPOSE: This study aims to assess the effects of intravenous racemic ketamine on global depression severity and individual depressive symptoms in patients with treatment-resistant depression.
METHODS: This retrospective, exploratory cohort study includes 74 consecutive adult patients treated in an outpatient specialty psychiatric clinic with serial racemic ketamine infusions for treatment-resistant depression between April 2019 and May 2023. Depression symptoms were assessed using the Montgomery-Åsberg Depression Rating Scale and Patient-Health Questionnaire-9 over 10 treatment sessions. Adverse effects were captured during treatment. Analyses considered changes in individual item and total depression rating scale scores, as well as the proportion of cases who manifested clinical response (change of >49%) and remission at each studied time point.
RESULTS: Results revealed significant and persistent reductions over time in both Montgomery-Åsberg Depression Rating Scale and Patient-Health Questionnaire-9 total scores, as well as in all individual items on both scales (all P s < 0.001). Depression rating scale scores did not significantly change from treatment session 4 to session 10. Side effect burden was no greater in higher doses as compared with lower.
CONCLUSIONS: Maintenance intravenous racemic ketamine therapy demonstrated significant, persistent, and broad efficacy for treatment-resistant depression as demonstrated by reductions in Montgomery-Åsberg Depression Rating Scale and Patient-Health Questionnaire-9 total scores and equivocal changes in every item on both rating scales. The magnitude of change in individual items was similar to that of previous randomized trials, with suicidal ideation and depression demonstrating the largest response and appetite disturbance the least.
Psychedelic Science