Psychopharmacology
September 1, 2012
Chad J Reissig, Lawrence P Carter, Matthew W Johnson et al.
89 citations
High doses of the cough suppressant dextromethorphan (DXM) produce perceptual changes, mystical-type experiences, and physiological effects similar to those of classic hallucinogens like psilocybin. In a double-blind study, 12 healthy volunteers with histories of hallucinogen use received single oral doses of DXM ranging from 100 to 800 mg/70 kg, triazolam, or placebo. DXM dose-dependently increased blood pressure, heart rate, and emesis, and elicited observer-rated hallucinogen-like effects such as visual distortions and joy. After 400 mg/70 kg DXM, 11 of 12 participants thought they had received a classic hallucinogen. At a 1-month follow-up, volunteers reported lasting positive changes in spirituality, attitudes, and mood attributed to the session.
Drug and alcohol dependence
March 1, 2013
Lawrence P Carter, Chad J Reissig, Matthew W Johnson et al.
28 citations
Acute high doses of dextromethorphan (DXM) impair attention, working memory, episodic memory, and metacognition in healthy volunteers with histories of hallucinogen use. Impairments from 100–300 mg/70 kg DXM were generally smaller than those from 0.5 mg/70 kg triazolam. Doses needed to match triazolam's impairment exceeded 10–30 times the therapeutic dose. Supratherapeutic doses caused impairments on all tasks, indicating a broad therapeutic window for over-the-counter DXM when used appropriately, but relevance to high-dose abuse.
Psychopharmacology
March 1, 2013
Lawrence P Carter, Bethea A Kleykamp, Roland R Griffiths et al.
19 citations
Ketamine causes less cognitive impairment than triazolam at doses that produce greater subjective effects, and unlike triazolam, it does not lead to an underestimation of impairment. In a double-blind study with 20 healthy volunteers, ketamine impaired balance only when assessed early, while triazolam impaired psychomotor coordination and divided attention regardless of task order. Triazolam also tended to impair working memory and episodic memory more than ketamine at doses that produced lower subjective effects and higher performance estimates.