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Cognitive and subjective dose-response effects of acute oral Delta 9-tetrahydrocannabinol (THC) in infrequent cannabis users.
Psychopharmacology (Berl) 2002; 164(1):61-70P

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.

Authors+Show Affiliations

Psychopharmacology Laboratories, Clinical Health Psychology, University College London, Gower Street, London WC1 6BT, UK. v.curran@ucl.ac.ukNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Comparative Study
Controlled Clinical Trial
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12373420

Citation

Curran, H Valerie, et al. "Cognitive and Subjective Dose-response Effects of Acute Oral Delta 9-tetrahydrocannabinol (THC) in Infrequent Cannabis Users." Psychopharmacology, vol. 164, no. 1, 2002, pp. 61-70.
Curran HV, Brignell C, Fletcher S, et al. Cognitive and subjective dose-response effects of acute oral Delta 9-tetrahydrocannabinol (THC) in infrequent cannabis users. Psychopharmacology (Berl). 2002;164(1):61-70.
Curran, H. V., Brignell, C., Fletcher, S., Middleton, P., & Henry, J. (2002). Cognitive and subjective dose-response effects of acute oral Delta 9-tetrahydrocannabinol (THC) in infrequent cannabis users. Psychopharmacology, 164(1), pp. 61-70.
Curran HV, et al. Cognitive and Subjective Dose-response Effects of Acute Oral Delta 9-tetrahydrocannabinol (THC) in Infrequent Cannabis Users. Psychopharmacology (Berl). 2002;164(1):61-70. PubMed PMID: 12373420.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cognitive and subjective dose-response effects of acute oral Delta 9-tetrahydrocannabinol (THC) in infrequent cannabis users. AU - Curran,H Valerie, AU - Brignell,Catherine, AU - Fletcher,Sally, AU - Middleton,Paul, AU - Henry,John, Y1 - 2002/07/23/ PY - 2002/01/31/received PY - 2002/06/03/accepted PY - 2002/10/10/pubmed PY - 2003/1/8/medline PY - 2002/10/10/entrez SP - 61 EP - 70 JF - Psychopharmacology JO - Psychopharmacology (Berl.) VL - 164 IS - 1 N2 - 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. SN - 0033-3158 UR - https://www.unboundmedicine.com/medline/citation/12373420/Cognitive_and_subjective_dose_response_effects_of_acute_oral_Delta_9_tetrahydrocannabinol__THC__in_infrequent_cannabis_users_ L2 - https://dx.doi.org/10.1007/s00213-002-1169-0 DB - PRIME DP - Unbound Medicine ER -