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Title: The acute cognitive, psychological and electrophysiological effects of cannabis constituents
Author: Englund, Amir
ISNI:       0000 0004 5369 1319
Awarding Body: King's College London (University of London)
Current Institution: King's College London (University of London)
Date of Award: 2015
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The cannabis available in many countries has been changing in recent years to favour a product increasingly high in its main component, the cannabinoid Δ9-THC. Epidemiological studies have highlighted that early, persistent and heavy cannabis use, particularly for cannabis high in Δ9-THC, is associated with an increased risk of development of schizophrenia. However, cannabis is a complex plant which also produces over 100 other cannabis compounds, each with a unique pharmacological profile. Cannabinoids such as CBD and Δ9-THCV, which are virtually absent from cannabis sold on the black market in the UK today, may interfere pharmacologically with Δ9-THC and therefore protect against the negative effects associated with cannabis use. This thesis is comprised of two experimental studies in healthy volunteers where the cognitive, psychological and electrophysiological effects of Δ9-THC, CBD and Δ9-THCV are explored. Study 1: In the first part of study 1, the psychological and cognitive effects of Δ9-THC and CBD were explored in a placebo-controlled, between-subjects design with 48 healthy volunteers. Pre-treatment with CBD (600mg, oral) significantly inhibited IV Δ9-THCinduced (1.5mg) paranoia and impairments to delayed verbal recall. Also, significantly fewer participants experienced clinically significant psychotic symptoms following IV Δ9-THC if pre-treated with CBD compared to placebo. In the second part of study 1, the electrophysiological effects of Δ9-THC and CBD were explored in the same sample, although the data from three participants were excluded. I found that Δ9-THC significantly reduced theta amplitude and coherence, although these were not correlated with psychopathology or inhibited by CBD. However, Δ9-THC-induced increases of alpha and delta amplitude was significantly inhibited by CBD. Study 2: The second study was a within-subject, placebo-controlled, cross-over design study (N=10), exploring the effects of IV Δ9-THC (1mg) and Δ9-THCV (10mg/day oral for 5 days) in healthy male volunteers with minimal past cannabis use. I found that Δ9-THC did not produce significant increases in paranoia or psychosis, or impairments to immediate verbal recall. Δ9-THCV significantly inhibited Δ9-THC-induced heart-rate increase and impairments to delayed verbal recall. Δ9-THCV on its own produced a significant improvement in reverse digit span, and a trend towards increased anxiety. Together, these results highlight the important protective role that CBD and Δ9-THCV play in recreational cannabis use against the negative effects of Δ9-THC. It also raises the possibility that CBD and Δ9-THCV may hold therapeutic value for mental illness and cognitive impairment.
Supervisor: Murray, Robin MacGregor; Stone, James Michael Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available