Chunk #20 — Do cannabinoids cause short-lived positive psychotic symptoms, negative symptoms and cognitive deficits in the general population? — Cognitive deficits
Δ9-THC produced dose-dependent impairments in immediate and delayed (+30 min) recall of a word list in healthy subjects (Fig. 2). Δ9-THC also increased the number of false-positive responses and intrusions during recall. More recently, Henquet et al. [94] showed that smoked Δ9-THC impaired verbal learning and recall, sustained attention, selective attention, and psychomotor speed in healthy subjects, schizophrenia patients, and relatives of patients with schizophrenia. The observations of Henquet [94] and D’Souza [46] are consistent with other reports showing acute dose-related effects of cannabinoids on learning, short-term memory, working memory, executive function, abstract ability, decision-making, and attention in humans [87, 90, 99, 129, 140, 153, 183]. Of note, impairments in memory, executive function, and attention are observed in schizophrenia [89]. The memory impairment produced by cannabinoids is perhaps their most reliable and robust effect [183], and impairment in verbal memory is also the most robust cognitive deficit observed in schizophrenia [89].
