Format

Send to

Choose Destination
Psychopharmacology (Berl). 2002 Oct;164(1):61-70. Epub 2002 Jul 23.

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

Author information

1
Psychopharmacology Laboratories, Clinical Health Psychology, University College London, Gower Street, London WC1 6BT, UK. v.curran@ucl.ac.uk

Abstract

RATIONALE:

Although some aspects of memory functions are known to be acutely impaired by delta(9)-tetrahydrocannabinol (delta(9)-THC; the main active constituent of marijuana), effects on other aspects of memory are not known and the time course of functional impairments is unclear.

OBJECTIVE:

The present study aimed to detail the acute and residual cognitive effects of delta(9)-THC in infrequent cannabis users.

METHODS:

A balanced, double-blind cross-over design was used to compare the effects of 7.5 mg and 15 mg delta(9)-THC with matched placebo in 15 male volunteers. Participants were assessed pre and 1, 2, 4, 6, 8, 24 and 48 h post-drug.

RESULTS:

Delta(9)-THC 15 mg impaired performance on two explicit memory tasks at the time of peak plasma concentration (2 h post-drug). At the same time point, performance on an implicit memory task was preserved intact. The higher dose of delta(9)-THC resulted in no learning whatsoever occurring over a three-trial selective reminding task at 2 h. Working memory was generally unaffected by delta(9)-THC. In several tasks, delta(9)-THC increased both speed and error rates, reflecting "riskier" speed-accuracy trade-offs. Subjective effects were also most marked at 2 h but often persisted longer, with participants rating themselves as "stoned" for 8 h. Participants experienced a strong drug effect, liked this effect and, until 4 h, wanted more oral delta(9)-THC. No effects of delta(9)-THC were found 24 or 48 h following ingestion indicating that the residual effects of oral delta(9)-THC are minimal.

CONCLUSIONS:

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.

PMID:
12373420
DOI:
10.1007/s00213-002-1169-0
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center