In a nonrandomized, open-label clinical trial, 74 adults with treatment-resistant depression received three intravenous ketamine infusions, with an additional four infusions for those who remitted. After the acute phase, 53% (39/74) experienced remission of depression symptoms. Higher baseline language domain scores on the RBANS cognitive assessment were associated with greater odds of remission. No significant association was found between remission and baseline immediate or delayed memory, visuospatial, or attention scores. During the continuation phase, improvements in immediate and delayed memory and attention persisted, with additional gains in visuospatial and language domains. The findings suggest cognitive improvement, not deterioration, with serial ketamine administration.
Among adults with treatment-resistant depression receiving ketamine or esketamine, those reporting high perceived stress before treatment had lower odds of remission and needed more treatment sessions to achieve remission. In a cohort of 39 patients, 66.7% had high perceived stress. Each 5-point increase on the Perceived Stress Scale reduced the odds of remission by 60%, independent of baseline depression severity. Patients with high stress required a median of 3 treatments to reach remission versus 1 for those with low-to-moderate stress. The observational design and lack of a placebo group limit the findings.