A series of ketamine infusions reduced PTSD symptoms by up to 30% from baseline compared to treatment with midazolam, which reduced symptoms by 20% over the same period. Ketamine treatment significantly reduced three of four PTSD associated symptoms, including intrusive thoughts, avoidance, and negative alterations in cognition and mood.
Higher doses of ketamine administered to sheep completely reduced brain activity for a short period. Researchers report as the drug wore off and consciousness was regained, the animals' brain activity switched between high and low-frequency oscillations. The timing of the brain activity corresponds to the time human users report experiencing feelings that their brain 'disconnected' from their bodies after ketamine use.
NMDA receptor hypofunction is involved in the reduction of sleep spindles and delta oscillations, which appear in the brain during deep natural sleep. Findings confirm the role NMDA receptors play in sleep disorders that accompany psychotic states.
Brain connections strengthened with treatment from fast-acting antidepressants, such as ketamine, are consolidated during deep sleep. Researchers propose rapid antidepressant treatments share the ability to regulate both synaptic potentiation and homeostatic mechanisms, which may contribute to how the brain reorganizes its activity to defeat depression.