Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Psychopharmacology (Berl). 2011 Mar;214(2):391-401. doi: 10.1007/s00213-010-2042-1. Epub 2010 Oct 30.

Tolerance and cross-tolerance to neurocognitive effects of THC and alcohol in heavy cannabis users.

Author information

  • 1Department Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands. j.ramaekers@maastrichtuniversity.nl

Abstract

INTRODUCTION:

Previous research has shown that heavy cannabis users develop tolerance to the impairing effects of Δ9-tetrahydrocannabinol (THC) on neurocognitive functions. Animal studies suggest that chronic cannabis consumption may also produce cross-tolerance for the impairing effects of alcohol, but supportive data in humans is scarce.

PURPOSE:

The present study was designed to assess tolerance and cross-tolerance to the neurocognitive effects of THC and alcohol in heavy cannabis users.

METHODS:

Twenty-one heavy cannabis users participated in a double-blind, placebo-controlled, three-way study. Subjects underwent three alcohol-dosing conditions that were designed to achieve a steady blood alcohol concentration of about 0, 0.5, and 0.7 mg/ml during a 5-h time window. In addition, subjects smoked a THC cigarette (400 μg/kg) at 3 h post-onset of alcohol dosing during every alcohol condition. Performance tests were conducted repeatedly between 0 and 7 h after onset of drinking and included measures of perceptual motor control (critical tracking task), dual task processing (divided-attention task), motor inhibition (stop-signal task), and cognition (Tower of London).

RESULTS:

Alcohol significantly impaired critical tracking, divided attention, and stop-signal performance. THC generally did not affect task performance. However, combined effects of THC and alcohol on divided attention were bigger than those by alcohol alone.

CONCLUSION:

In conclusion, the present study generally confirms that heavy cannabis users develop tolerance to the impairing effects of THC on neurocognitive task performance. Yet, heavy cannabis users did not develop cross-tolerance to the impairing effects of alcohol, and the presence of the latter even selectively potentiated THC effects on measures of divided attention.

PMID:
21049267
[PubMed - indexed for MEDLINE]
PMCID:
PMC3045517
Free PMC Article

Images from this publication.See all images (5)Free text

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for Springer Icon for PubMed Central
    Loading ...
    Write to the Help Desk