Effect of high-potency cannabis on corpus callosum microstructure

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Title: Effect of high-potency cannabis on corpus callosum microstructure
Author(s): Rigucci, S
Marques, TR
Di Forti, M
Taylor, H
Dell'Acqua, F
Mondelli, V
Bonaccorso, S
Simmons, A
David, AS
Girardi, P
Pariante, CM
Murray, RM
Dazzan, P
Item Type: Journal Article
Abstract: BACKGROUND: The use of cannabis with higher Δ9-tetrahydrocannabinol content has been associated with greater risk, and earlier onset, of psychosis. However, the effect of cannabis potency on brain morphology has never been explored. Here, we investigated whether cannabis potency and pattern of use are associated with changes in corpus callosum (CC) microstructural organization, in patients with first-episode psychosis (FEP) and individuals without psychosis, cannabis users and non-users. METHOD: The CC of 56 FEP (37 cannabis users) and 43 individuals without psychosis (22 cannabis users) was virtually dissected and segmented using diffusion tensor imaging tractography. The diffusion index of fractional anisotropy, mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity was calculated for each segment. RESULTS: Across the whole sample, users of high-potency cannabis had higher total CC MD and higher total CC AD than both low-potency users and those who never used (p = 0.005 and p = 0.004, respectively). Daily users also had higher total CC MD and higher total CC AD than both occasional users and those who never used (p = 0.001 and p < 0.001, respectively). However, there was no effect of group (patient/individuals without psychosis) or group x potency interaction for either potency or frequency of use. The within-group analysis showed in fact that the effects of potency and frequency were similar in FEP users and in users without psychosis. CONCLUSIONS: Frequent use of high-potency cannabis is associated with disturbed callosal microstructural organization in individuals with and without psychosis. Since high-potency preparations are now replacing traditional herbal drugs in many European countries, raising awareness about the risks of high-potency cannabis is crucial.
Publication Date: 27-Nov-2015
Date of Acceptance: 2-Oct-2015
ISSN: 1469-8978
Publisher: Cambridge University Press
Start Page: 841
End Page: 854
Journal / Book Title: Psychological Medicine
Volume: 46
Issue: 4
Copyright Statement: © Cambridge University Press 2015. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (, which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Keywords: Cannabis
corpus callosum
first-episode psychosis
white matter
1701 Psychology
1117 Public Health And Health Services
1109 Neurosciences
Publication Status: Published
Appears in Collections:Clinical Sciences
Imaging Sciences
Faculty of Medicine

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