Chunk #11 — Do cannabinoids cause short-lived positive psychotic symptoms, negative symptoms and cognitive deficits in the general population? — Experimental evidence
the effects of varying doses of Δ9-THC in 40 former opiate addicts. At a dose of Δ9-THC, 120 μg/kg orally and 50 μg/kg smoking, in addition to recognizing the effects as being similar to cannabis, the subjects reported alterations in visual, auditory, and time perception. However, at Δ9-THC doses of 300–480 μg/kg orally and 200–250 μg/kg by smoking, there were marked auditory and visual distortions, depersonalization, derealization, and hallucinations. Of note, “occasional” individuals experienced psychosis even at low doses of Δ9-THC. In a related study, Isbell and Jasinski [104] compared the effects of Δ9-THC (75–225 μg/kg, smoked) and LSD (0.5–1.5) in ten “normal” controls. Both drugs produced perceptual distortions, mood changes and, at higher doses, hallucinations. Of note, two subjects dropped out from the study after experiencing psychotic “reactions” from Δ9-THC. Melges et al. [151], in a double-blind placebo-controlled study with high and low dose Δ9-THC, reported that cannabis users were noted to have core symptoms of psychosis, including thought disorder and paranoia. The authors specifically described “tracking difficulties” that subjects reported, including racing thoughts, thought blocking, losing their train of thought, etc. Jones et al. [110] did not observe robust psychotomimetic effects in studies of “normal” controls with Δ9-THC
