Does Cannabis Composition Matter? Differential Effects of Delta-9-tetrahydrocannabinol and Cannabidiol on Human Cognition

Abstract

Purpose of ReviewThe lack of clarity about the effect of cannabis use on cognition may be attributable to the considerable heterogeneity among studies in terms of cannabis composition. This article selectively reviews studies examining the distinctive effects of cannabinoids on human cognition, particularly those of delta-9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD).Recent FindingsResearch indicates that ∆9-THC administration acutely impairs cognition, particularly memory and emotional processing. Limited evidence suggests that CBD administration might improve cognition in cannabis users but not in individuals with neuropsychiatric disorders. Moreover, studies indicate that some acute Δ9-THC-induced cognitive impairments may be prevented if Δ9-THC is administered in combination or following CBD treatment. Δ9-THC and CBD have also shown opposite effects on cognition-related brain activation, possibly reflecting their antagonistic behavioral effects.SummaryResearch suggests greater cognitive impairments in individuals when exposed to high ∆9-THC or low CBD cannabis. It is unclear whether at specific concentrations CBD might outweigh any harmful effects of Δ9-THC on cognition.

Positive and Negative Effects of Cannabis and Cannabinoids on Health

“…Second, it seems that cannabis‐induced psychosis is dose dependent . Cannabinoid‐based drugs that contain high‐potent cannabinoids and less CBD are associated with greater psychotic symptoms as well as more persistent and long‐lasting psychotic episodes than low‐potent cannabis . Altogether, this evidence supports the view that additional factors, including genetic predisposition, age of onset of cannabis use, dose, and cannabinoid content may moderate the potential side effects of cannabinoid‐based drugs on the brain and mental health.…”

“…There is evidence that as the content of THC is increased, the risk potential of developing psychotic disorder due to cannabis use increases . On the other hand, a high level of CBD is associated with fewer psychotic experiences and generally lower adverse effects . The last notions are crucial because the content of cannabinoids within cannabis drugs has been significantly changed in recent years .…”

“…[26][27][28] On the other hand, a high level of CBD is associated with fewer psychotic experiences and generally lower adverse effects. 29 The last notions are crucial because the content of cannabinoids within cannabis drugs has been significantly changed in recent years. 30 In several countries across Europe, the average THC content in cannabis has significantly increased between 5% and 17%, whereas the CBD content has diminished significantly.…”

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“…Although THC is the primary cannabis constituent responsible for its harmful effects, CBD may offset some of these harms [15][16][17]. For example, some (but not all [44]) studies have reported that the acute effects of THC on verbal memory impairment [45,46] and psychotic-like symptoms [46,47] were partially offset when CBD was co-administered with THC.…”

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“…). CBD does not have the same psychoactive effects as THC and may counteract some of its behavioural and cognitive effects when the two are co‐administered (Colizzi & Bhattacharyya ; Boggs et al . ).…”