The incidence of unpleasant dreams after sub-anaesthetic ketamine.
Psychopharmacology March 1, 2009 Mark Blagrove, Celia J. A. Morgan, H Valerie Curran et al.
Ketamine, an NMDA receptor antagonist, increases the unpleasantness of dreams for three nights after a sub-anaesthetic dose. In a placebo-controlled study with 30 healthy volunteers, those given ketamine reported significantly more unpleasant dreams, with a threefold increase in the odds of having an unpleasant dream. The number of dreams recalled did not differ between groups. People who already had frequent nightmares at home were more likely to have unpleasant dreams after ketamine. This effect may reflect a lingering psychotogenic influence or disrupted sleep physiology not captured by standard symptom questionnaires.