, Volume 188, Issue 4, pp 425–444

The acute effects of cannabinoids on memory in humans: a review




Cannabis is one of the most frequently used substances. Cannabis and its constituent cannabinoids are known to impair several aspects of cognitive function, with the most robust effects on short-term episodic and working memory in humans. A large body of the work in this area occurred in the 1970s before the discovery of cannabinoid receptors. Recent advances in the knowledge of cannabinoid receptors’ function have rekindled interest in examining effects of exogenous cannabinoids on memory and in understanding the mechanism of these effects.


The literature about the acute effects of cannabinoids on memory tasks in humans is reviewed. The limitations of the human literature including issues of dose, route of administration, small sample sizes, sample selection, effects of other drug use, tolerance and dependence to cannabinoids, and the timing and sensitivity of psychological tests are discussed. Finally, the human literature is discussed against the backdrop of preclinical findings.


Acute administration of Δ-9-THC transiently impairs immediate and delayed free recall of information presented after, but not before, drug administration in a dose- and delay-dependent manner. In particular, cannabinoids increase intrusion errors. These effects are more robust with the inhaled and intravenous route and correspond to peak drug levels.


This profile of effects suggests that cannabinoids impair all stages of memory including encoding, consolidation, and retrieval. Several mechanisms, including effects on long-term potentiation and long-term depression and the inhibition of neurotransmitter (GABA, glutamate, acetyl choline, dopamine) release, have been implicated in the amnestic effects of cannabinoids. Future research in humans is necessary to characterize the neuroanatomical and neurochemical basis of the memory impairing effects of cannabinoids, to dissect out their effects on the various stages of memory and to bridge the expanding gap between the humans and preclinical literature.


Cannabinoids Cannabis Marijuana Δ-9-THC Memory Learning Cognition 





cannabinoid 1 receptor





Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Mohini Ranganathan
    • 1
    • 2
    • 3
  • Deepak Cyril D’Souza
    • 1
    • 2
    • 3
    • 4
  1. 1.Schizophrenia Biological Research CenterVA Connecticut Healthcare SystemWest-HavenUSA
  2. 2.Abraham Ribicoff Research FacilitiesConnecticut Mental Health CenterNew HavenUSA
  3. 3.Department of PsychiatryYale University School of MedicineNew HavenUSA
  4. 4.Psychiatry Service, 116AVA Connecticut Healthcare SystemWest HavenUSA

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