How Ketamine Affects Sleep and Circadian Rhythms in MDD and Bipolar Disorder: A Systematic Review
TL;DR
Systematic review (26 studies, n=1694) finds ketamine associated with improved subjective sleep quality; baseline sleep disturbance and early sleep improvements may predict antidepressant response; REM sleep changes as potential biomarker.
Research Background
Ketamine and its enantiomer esketamine have gained significant attention as rapid-acting antidepressants, yet their mechanisms remain incompletely understood. Emerging evidence suggests that modulation of sleep and circadian rhythms may be a key mechanism underlying ketamine's antidepressant effects.
A 2026 systematic review published in the Journal of Affective Disorders by researchers from the University of Groningen systematically searched PubMed, Embase, PsycINFO, and Web of Science, identifying 26 studies (N=1,694) examining the association between ketamine treatment and sleep/circadian measures in patients with major depressive disorder (MDD) and bipolar disorder (BD).
Key Findings
1. Significant Improvement in Subjective Sleep Quality
Patients showed significant improvements in subjective sleep measures (PSQI) following ketamine treatment. These improvements appeared within 24-48 hours after a single infusion, contrasting sharply with the weeks-long onset of conventional antidepressants.
2. Baseline Sleep Disturbance Predicts Treatment Response
Patients with more severe sleep disturbance at baseline showed better antidepressant response to ketamine. This finding suggests sleep measures may serve as predictive biomarkers for ketamine efficacy.
3. REM Sleep as a Potential Biomarker
| Measure | Ketamine Effect | Clinical Significance |
|---|---|---|
| REM latency | Prolonged | Associated with antidepressant response |
| REM density | Reduced | May reflect improved emotion regulation |
| Slow-wave sleep | Trend toward increase | Related to enhanced synaptic plasticity |
| Subjective sleep quality | Improved | Correlated with depression score improvement |
4. Preliminary Circadian Evidence
Preliminary evidence suggests ketamine may positively affect objective circadian measures (activity-rest rhythms, melatonin secretion), though limited studies warrant cautious interpretation.
What This Means
Sleep improvement may be a core mechanism of ketamine's antidepressant effects, not merely a byproduct of symptom relief.
Sleep measures as precision medicine tools: Baseline sleep disturbance helps identify patients most likely to benefit from ketamine.
REM sleep as a biomarker offers new targets for developing more精准 rapid antidepressant treatments.
Ketamine + sleep intervention synergy deserves exploration: Combining sleep hygiene or chronotherapy may enhance efficacy.
Study Limitations
- High methodological heterogeneity across included studies
- Limited studies with objective sleep and circadian measures
- Most studies had short follow-up; long-term effects unknown
- Differences between esketamine and ketamine need further research