Cognitive and subjective dose-response effects of acute oral Δ 9 -tetrahydrocannabinol (THC) in infrequent cannabis users

Abstract

These data demonstrate that oral delta(9)-THC impairs episodic memory and learning in a dose-dependent manner whilst sparing perceptual priming and working memory.

The Psychotomimetic Effects of Intravenous Delta-9-Tetrahydrocannabinol in Healthy Individuals: Implications for Psychosis

“…The effects of D-9-THC on immediate and delayed verbal recall are in agreement with the current study. However, whereas we found that D-9-THC impaired performance on a computerized visual working memory for shapes, Curran et al (2002) did not find an effect on a relatively simpler task of working memory, the serial sevens task. Our data are consistent with an extensive animal literature showing a robust effect of cannabinoids on working memory (reviewed in Lichtman et al, 2002).…”

“…Our data are consistent with an extensive animal literature showing a robust effect of cannabinoids on working memory (reviewed in Lichtman et al, 2002). When the rapid visual processing task of sustained attention was made more demanding in our study similar to the task of Curran (2002), D-9-THC appeared to impair performance. Consistent with this, several subjects reported that after receiving D-9-THC, irrelevant sounds and visual patterns that were previously in the background, for example, the sound of the airconditioner or the pattern of the curtains, came to the foreground and was perceived as distracting.…”

“…While cannabis has been reported to impair several aspects of cognitive functioning in a dose-related manner, deficits in verbal recall appear to be the most consistent finding in laboratory studies (Belmore and Miller, 1980;Chait and Zacny, 1992;Curran et al, 2002;Hart et al, 2001;Heishman et al, 1997Heishman et al, , 1990Hooker and Jones, 1987;Marks and MacAvoy, 1989;Miller and Branconnier, 1983;Miller et al, 1977). Our data are consistent with these effects.…”

“…In contrast to our study, Hart et al (2001) found minimal effects of D-9-THC on cognitive test performance; however, the subjects were cannabis dependent and were smoking an average of four cannabis joints per day for several years. Curran et al (2002) studied subjects who had similar cannabis use histories to our subjects. However, relative to our study, Curran et al (2002) used oral D-9-THC which achieved much lower plasma levels, employed some different cognitive tasks, and administered those tasks at different timepoints in the D-9-THC dose-response curve.…”

“…Curran et al (2002) studied subjects who had similar cannabis use histories to our subjects. However, relative to our study, Curran et al (2002) used oral D-9-THC which achieved much lower plasma levels, employed some different cognitive tasks, and administered those tasks at different timepoints in the D-9-THC dose-response curve. The effects of D-9-THC on immediate and delayed verbal recall are in agreement with the current study.…”