Neurocognitive Effects of Ketamine for Depression Examined

Findings based on a systematic literature review of studies reporting the use of ketamine, esketamine for treatment-resistant depression

MONDAY, Aug. 30, 2021 (HealthDay News) — Use of ketamine and esketamine for their antidepressant effects does not seem to have harmful neurocognitive effects in individuals with treatment-resistant depression, according to a review published online Aug. 5 in the Harvard Review of Psychiatry.

Breno Souza-Marques, from Faculdade de Medicina da Bahia in Brazil, and colleagues conducted a systematic literature review to identify studies examining the neurocognitive effects of ketamine and esketamine in patients with treatment-resistant major depressive disorder.

Fourteen studies were identified. The researchers found that one study reported impairment of processing speed and verbal memory after ketamine treatment, while five studies reported improvements in processing speed, verbal memory, visual memory, working memory, or cognitive flexibility. No performance changes were found in the esketamine study. Predictors of antidepressant response include lower attention, slower processing speed, and higher working memory. A normalizing tendency after ketamine was seen in brain areas for emotional and reward processing, including the amygdala, insula, and orbitofrontal cortex.

“Ketamine and esketamine do not seem to exert significant deleterious neurocognitive effects in the short or long term in individuals with treatment-resistant depression,” the authors write. “Results suggest neuropsychological functions and brain areas commonly impaired in treatment-resistant depression may especially benefit from subanesthetic ketamine infusions.”