Disentangling the association of depression on the anti-fatigue effects of ketamine

In this study, ketamine did not have a unique effect on fatigue outside of its general antidepressant effects in patients with treatment-resistant depression. Specifically, the anti-fatigue effects of ketamine observed in this study seem to be explained by the effects of ketamine on two symptom domains of depression: amotivation and depressed mood. The study findings suggest that the anti-fatigue effects of ketamine should be assessed by fatigue-specific measures other than the NIH-BFI or future studies should enroll fatigued patients without depression.