Psychopharmacology
February 1, 2018
Theresa M Carbonaro, Matthew W Johnson, Ethan Hurwitz et al.
139 citations
Psilocybin and dextromethorphan (DXM) both produce powerful subjective effects, but their experiences differ profoundly. In a double-blind comparison with 20 participants, high doses of both drugs caused similar overall drug effect strength and time-course. Psilocybin uniquely fostered richer, more complex visual experiences—including more movement, brightness, and kaleidoscopic imagery—along with greater mystical-type and psychologically insightful experiences and deeper music absorption. DXM, by contrast, produced stronger feelings of disembodiment, nausea, and light-headedness. Both drugs increased blood pressure, heart rate, and pupil dilation while impairing motor performance and balance.
Psychopharmacology
October 1, 2018
Frederick S Barrett, Theresa M Carbonaro, Ethan Hurwitz et al.
109 citations
Classic psychedelics and dissociative hallucinogens may share some neuropsychological effects despite different pharmacology. In a double-blind, placebo-controlled study, 20 hallucinogen users received 10, 20, and 30 mg/70 kg psilocybin, 400 mg/70 kg dextromethorphan (DXM), and placebo across five sessions. Neither drug caused global cognitive impairment. Psilocybin produced dose-dependent effects on psychomotor performance, working memory, episodic memory, associative learning, and visual perception. DXM affected psychomotor performance, visual perception, and associative learning similarly to moderate-to-high psilocybin doses. Psilocybin affected working memory more than DXM, while DXM had greater effects on balance, episodic memory, response inhibition, and executive control.
Psychopharmacology
August 1, 2020
Theresa M Carbonaro, Matthew W Johnson, Roland R Griffiths
51 citations
Psilocybin produces stronger positive subjective effects than dextromethorphan (DXM) at comparable peak drug strength, which may explain its higher rates of non-medical use. In a double-blind study of 20 healthy participants with hallucinogen experience, psilocybin (10, 20, 30 mg/70 kg) and DXM (400 mg/70 kg) both increased ratings of overall drug effect, but psilocybin showed dose-related increases in nine domains linked to reinforcing effects—including liking, visual effects, positive mood, insight, social effects, appreciation of beauty, awe, meaningfulness, and mystical experience. For most ratings, the two highest psilocybin doses were significantly greater than DXM, and DXM never exceeded psilocybin. These differences matched participants' desire to take the drug again.
Psychopharmacology
March 1, 2013
Theresa M Carbonaro, Michael J Forster, Michael B Gatch
The hallucinogen DiPT, known for causing auditory distortions, produces discriminative stimulus effects in rats that are similar to those of other synthetic hallucinogens like LSD, DOM, and MDMA, but only partially similar to DMT and not similar to methamphetamine. Rats learned to distinguish DiPT from saline in about 60 training sessions. DiPT caused dose-dependent increases in drug-appropriate responding, reaching 99% at the highest dose. The effects began within 5 minutes and faded within 4 hours. The results suggest that DiPT's auditory effects do not make its discriminative stimulus profile distinct from other hallucinogens.