Table 1.

Characteristics and findings of systematic studies of psychotomimetic properties of PCP and ketamine.

Authors	Year	Design	Sample	NMDA Antagonist	Dose	Perceptual Findings
Luby et al.[1]	1959	Non-placebo-controlled PCP administration	9 TD; 9 SZ	Phencyclidine (PCP)	0.1mg/kg IV for 12 mins	Perceived limb lengthening; feelings of flying; complete change in setting to past experience; “sensory experiences were overvalued if not eroticized”; mild diminution in auditory and visual acuity
Lawes[7]	1963	2×3 dosage group vs. environmental stimulation level	8 TD	Phencyclidine (PCP)	Group A (N = 5): 5mg PO Group B (N = 3): 10mg PO	Amplification or alteration of quality of sounds, sharpening of vision, room expansion; body “lightness”; dose-response relationship observed
Oye [60]	1992	Double-blind crossover with 4 doses of 2 enantiomers, 2 placebo doses	6 TD	Ketamine	(S)-ketamine: 0.05, 0.1,0.15,0.2 mg/kg IV (R)-ketamine: 0.2, 0.4,0.6,0.8 mg/kg IV	Blurred vision, visual field narrowing; preoccupation with irrelevant environmental stimuli; sound amplification
Krystal et al.[2]	1994	Double-blind placebo-controlled 2-dose level crossover	19 TD	Ketamine	Low dose: 0.1mg/kg IV High dose: 0.5mg/kg IV	Increased perceived intensity or closeness within a discrete spatial field; no outright hallucinations noted
Vollenweider et al. [41]	1997	Within-subject placebo controlled counterbalanced	10 TD	Ketamine	Loading dose of 15mg IV racemic ketamine followed by continuous infusion 0.014–0.02mg/kg/min	Visual illusions as well as complex hallucinations present with (S)-ketamine administration; auditory hyperacusis but no hallucinations noted
Bowdle et al.[11]	1998	Single-blind placebo-controlled crossover	10 TD	Ketamine	IV administration set to keep plasma concentration at 0, 50, 100, 150, 200ng/ml in progressive steps	Hallucinations as rated on a visual analogue scale (“I heard voices or sounds that were not real”) differed significantly between ketamine and saline and correlated with plasma concentration; these experiences not described further.
Newcomer et al.[10]	1999	Double-blind placebo-controlled 3-dose level	15 TD	Ketamine	Loading: 0.27 mg/kg, 0.081 mg/kg, 0.0243 mg/kg IV Maintenance: 0.00225 mg/kg/min, 0.000675 mg/kg/min, and 0.0002025 mg/kg/min	Visual distortions (e.g., hands perceived as shrunken, “shadow of a body falling” noted in window); no outright hallucinations noted
Lahti et al.[40]	2001	2×2 Group by placebo vs. drug crossover	18 TD; 17 SZ	Ketamine	0.3mg/kg IV	Formed auditory hallucinations (e.g., articulated voices) in SZ subjects (despite low levels of positive symptoms outside drug administration), and in a minority of TD subjects; visual and olfactory hallucinations in both groups
Gouzoulis et al.	2005	Double-blind 2-drug, 2-dose crossover	15 TD	Ketamine and N,N-dimethyltryptamine (DMT)	Ketamine: 0.1mg/kg IV (Low) and 0.2mg/kg IV (High) DMT: 0.15mg/kg (Low) and 0.3mg/kg(High)	Limb lengthening and other somatic distortions; visual hallucinations present in 1 subject on ketamine; auditory distortions but no hallucinations reported. DMT with more pronounced visual and auditory phenomena, and musical hallucinations and whispers occurred in 2 cases; visual hallucinations on DMT were present in all subjects at high dose levels
Pamarol-Clotet et al.[8]	2006	Experimental case series for phenomenological description	15 TD	Ketamine	IV administration set to keep plasma concentration at 100ng/ml, then 200ng/ml	Increased sensitivity to noise and increased brightness of colors; loss of visual depth perception; alterations of perceived size, shape, or position of body parts; one participant reported sensing the presence of more people than were visibly present and hearing voices that were unable to be accounted for by those present.