CBD enhances verbal episodic memory — potentially counteracting the memory impairments associated with THC

Cannabidiol (CBD) may be able to counteract the adverse effects of tetrahydrocannabinol (THC) on memory, according to findings published in the Journal of Psychiatric Research. Participants who vaped CBD showed improved verbal episodic memory compared to those who vaped a placebo e-liquid.

Both scientific studies and reports from marijuana users suggest that cannabis has a negative effect on memory. It has been suggested that THC, the psychoactive component of cannabis, causes these cognitive deficits while another cannabis compound may actually counter these effects. There is preliminary evidence that CBD, a non-psychoactive component of cannabis, can instead improve verbal recall.

Study authors Janine Hotz and her colleagues say such findings are particularly interesting because they suggest a potential treatment option for psychiatric conditions affected by deteriorated verbal memory, such as dementia and post-traumatic stress disorder (PTSD). Since the early evidence remains mixed, Hotz and her team conducted a placebo-controlled experimental trial of their own.

A total of 34 healthy Swiss adults between the ages of 18 and 30 were included in the study. Participants completed various memory tasks on two separate study days which were virtually identical. However, on one of the days, participants vaped 12.5 mg of 5% CBD e-liquid, and on the other day, participants vaped a perfumed placebo e-liquid. All participants experienced both conditions but were randomly assigned to receive either the CBD or placebo first.

On the study days, participants learned three series of five unrelated words before vaping either the CBD or placebo for 15 minutes. Twenty minutes after learning the words, the participants were asked to recall as many of the words as they could as a test of episodic memory. Participants also completed an n-back task to assess working memory and attention.

The results revealed that participants performed better on the word recall task after vaping CBD compared to placebo. The average increase was around 10% and was unaffected by age, sex, depressive symptoms, or how often participants consumed cannabis within a year. Notably, there were no differences between the two conditions for either attention or working memory, suggesting that the CBD did not affect these cognitive functions. No participants reported any negative side effects beyond a headache (one participant in the CBD condition) or abdominal pain (one participant in the placebo condition).

Interestingly, participants with higher body mass index (BMI) experienced greater memory improvement with CBD. According to the study authors, this may suggest that those with lower BMI received too high of a CBD dose to achieve memory benefits.

The authors note that their study specifically tested the effects of CBD on memory recall 20 minutes after encoding the words. Further study is needed, they say, to shed light on how CBD impacts the consolidation of memories and the retrieval process. The overall findings suggest that CBD is a drug with potential therapeutic effects that may prove to attenuate deficits in episodic memory. Similar trials should be conducted among patients with episodic memory deficits.

The study, “Cannabidiol enhances verbal episodic memory in healthy young participants: A randomized clinical trial”, was authored by Janine Hotz, Bernhard Fehlmann, Andreas Papassotiropoulos, Dominique JF. de Quervain, and Nathalie S. Schicktanz.