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cbd and memory

Learning and memory is modulated by cannabidiol when administered during trace fear-conditioning

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Highlights

Mice given CBD prior to trace fear conditioning were resistant to extinction.

Contextual fear was enhanced when CBD was given prior to trace fear conditioning.

Generalized fear was enhanced when CBD was given prior to trace fear conditioning.

Synaptic plasticity in the amygdala and hippocampus was altered by CBD.

Abstract

Cannabidiol (CBD) is thought to have therapeutic potential for treating psychiatric conditions that affect cognitive aspects of learning and memory, including anxiety and post-traumatic stress disorder (PTSD). Studies have shown that CBD enhances extinction of fear memory when given after conditioning. This led us to hypothesize that CBD, if administered prior to fear conditioning, might modulate cognitive learning and memory processes in additional ways that would further guide its potential use for treating PTSD. Therefore, we designed a study to investigate effects of CBD on fear learning and memory when administered to mice prior to administering a trace fear conditioning protocol which imposes cognitive demands on the learning and memory process. We show that CBD-treated animals had increased levels of freezing during conditioning, enhanced generalized fear, inhibited cue-dependent memory extinction, slightly increased levels of freezing during an auditory-cued memory test, and increased contextual fear memory. Because synaptic plasticity is the fundamental mechanism of learning and memory, we also evaluated the impact of CBD on trace conditioning-dependent dendritic spine plasticity which occurred in the dorsal lateral amygdala and CA1 region of the ventral hippocampus. We showed that CBD mildly enhanced spine densities independent of conditioning, and inhibited conditioning-dependent spine increases in the hippocampi, but not the amygdala of fear conditioned animals. Overall, the memory-modulating effects of a single pre-conditioning dose of CBD, which we show here, demonstrate the need to more fully characterize its basic effects on memory, suggest caution when using it clinically as an anxiolytic, and point to a need for more research into its potential as a therapeutic for treating memory-loss disorders.

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Learning and memory is modulated by cannabidiol when administered during trace fear-conditioning Add to Mendeley Highlights Mice given CBD prior to trace fear conditioning were resistant to

Impact of cannabidiol on the acute memory and psychotomimetic effects of smoked cannabis: naturalistic study: naturalistic study [corrected]

Affiliation

  • 1 Clinical Psychopharmacology Unit, University College London, Gower St, London WC1E 6BT, UK.
  • PMID: 20884951
  • DOI: 10.1192/bjp.bp.110.077503

Impact of cannabidiol on the acute memory and psychotomimetic effects of smoked cannabis: naturalistic study: naturalistic study [corrected]

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Authors

Affiliation

  • 1 Clinical Psychopharmacology Unit, University College London, Gower St, London WC1E 6BT, UK.
  • PMID: 20884951
  • DOI: 10.1192/bjp.bp.110.077503

Erratum in

  • Br J Psychiatry. 2010 Nov;197:416

Abstract

Background: The two main constituents of cannabis, cannabidiol and Δ(9)-tetrahydrocannabinol (THC), have opposing effects both pharmacologically and behaviourally when administered in the laboratory. Street cannabis is known to contain varying levels of each cannabinoid.

Aims: To study how the varying levels of cannabidiol and THC have an impact on the acute effects of the drug in naturalistic settings.

Method: Cannabis users (n = 134) were tested 7 days apart on measures of memory and psychotomimetic symptoms, once while they were drug free and once while acutely intoxicated by their own chosen smoked cannabis. Using an unprecedented methodology, a sample of cannabis (as well as saliva) was collected from each user and analysed for levels of cannabinoids. On the basis of highest and lowest cannabidiol content of cannabis, two groups of individuals were directly compared.

Results: Groups did not differ in the THC content of the cannabis they smoked. Unlike the marked impairment in prose recall of individuals who smoked cannabis low in cannabidiol, participants smoking cannabis high in cannabidiol showed no memory impairment. Cannabidiol content did not affect psychotomimetic symptoms, which were elevated in both groups when intoxicated.

Conclusions: The antagonistic effects of cannabidiol at the CB(1) receptor are probably responsible for its profile in smoked cannabis, attenuating the memory-impairing effects of THC. In terms of harm reduction, users should be made aware of the higher risk of memory impairment associated with smoking low-cannabidiol strains of cannabis like ‘skunk’ and encouraged to use strains containing higher levels of cannabidiol.

The antagonistic effects of cannabidiol at the CB(1) receptor are probably responsible for its profile in smoked cannabis, attenuating the memory-impairing effects of THC. In terms of harm reduction, users should be made aware of the higher risk of memory impairment associated with smoking low-canna …