Therapeutic Ketamine

Results: Sample patients (n = 215) had a mean baseline PHQ-9 score of 18.6 and a mean of 2.1 antidepressant medication trials in the past year and 6.1 antidepressant trials in the 20 years prior to their first ketamine infusion. Frequency of infusions decreased from every 5 days to every 3–4 weeks over the first 5 months of infusions, with a mean of 18 total infusions over 12 months. After 6 weeks of treatment, 26% had a 50% improvement in PHQ-9 score (response) and 15% had PHQ-9 score ≤ 5 (remission). These improvements were similar at 12 and 26 weeks. No demographic characteristics or comorbid diagnoses were associated with 6-week PHQ-9 scores.