Does ketamine disturb sleep?

Does Ketamine Disturb Sleep?

Ketamine does not disturb sleep; rather, it improves sleep architecture by increasing slow-wave sleep (SWS) and total sleep time, though it causes emergence reactions (hallucinations, vivid dreams, delirium) in 10-30% of adults during the immediate post-administration period. 1, 2, 3

Immediate Post-Administration Effects (Not Sleep Disturbance)

The psychological phenomena associated with ketamine occur during emergence from anesthesia, not during actual sleep:

• Emergence reactions occur in approximately 12% of patients (FDA label) to 10-30% of adults (clinical guidelines), manifesting as floating sensations, vivid dreams, hallucinations, and emergence delirium 3, 1, 2
• These reactions typically last only a few hours, with rare recurrences up to 24 hours postoperatively, and no residual psychological effects are known 3
• The incidence is lowest in elderly patients (>65 years), less frequent with intramuscular administration, and can be reduced by minimizing verbal, tactile, and visual stimulation during recovery 3
• Co-administration with benzodiazepines like midazolam minimizes these emergence phenomena 1, 3

Actual Effects on Sleep Architecture (Beneficial)

Ketamine demonstrably improves sleep quality and architecture in patients with depression:

• Ketamine increases total sleep time, slow-wave sleep (SWS), slow-wave activity (SWA), and REM sleep in patients with major depressive disorder 4
• Objective EEG measurements show decreased nocturnal wakefulness accompanied by increases in both SWS and REM sleep 5
• In treatment-resistant depression, improvements in insomnia, night-time restlessness, early morning waking, and total sleep were significant partial mediators of ketamine's antidepressant effects 6
• Each point improvement in total sleep score was associated with a 3.29-fold increased likelihood of achieving responder/remitter status for depression 6

Mechanism of Sleep Enhancement

The sleep-promoting effects appear related to ketamine's glutamatergic mechanisms:

• Ketamine increases delta EEG intensity during NREM sleep, with this effect being among the largest pharmacologically induced stimulations of delta sleep observed 7
• After initial waking induced by ketamine administration, there is a subsequent increase in NREM sleep and EEG slow-wave activity 8
• The drug may exert anti-suicidal effects through normalizing sleep patterns 1

Clinical Context and Caveats

Important distinctions must be made between acute emergence phenomena and actual sleep disturbance:

• The FDA label warns about emergence reactions but does not classify these as sleep disturbances 3
• Insomnia is listed as a potential symptom of ketamine abuse/dependence with prolonged use, but this is distinct from therapeutic administration 3
• In the perioperative setting, low-dose ketamine (0.5-1.0 mg/kg) did not reduce postoperative delirium but did increase reports of hallucinations (20-28%) and nightmares (12-15%) compared to placebo (18% and 8% respectively) 1
• These nightmares and hallucinations occur during the emergence/recovery phase, not during natural sleep cycles 1

Practical Implications

For patients receiving ketamine therapeutically:

• Sleep quality typically improves rather than deteriorates, particularly in depression 6, 5, 4
• Emergence reactions are time-limited and can be managed by reducing stimulation during recovery and co-administering benzodiazepines 3
• The sleep-enhancing effects may contribute to ketamine's rapid antidepressant action 1, 4