title: The association between regular cannabis exposure and alterations of human brain morphology: an updated review of the literature.
abstract: Cannabis is the most widely used illicit drug worldwide, though it is unclear whether its regular use is associated with persistent alterations in brain morphology. This review examines evidence from human structural neuroimaging investigations of regular cannabis users and focuses on achieving three main objectives. These include examining whether the literature to date provides evidence that alteration of brain morphology in regular cannabis users: i) is apparent, compared to non-cannabis using controls; ii) is associated with patterns of cannabis use; and with iii) measures of psychopathology and neurocognitive performance. The published findings indicate that regular cannabis use is associated with alterations in medial temporal, frontal and cerebellar brain regions. Greater brain morphological alterations were evident among samples that used at higher doses for longer periods. However, the evidence for an association between brain morphology and cannabis use parameters was mixed. Further, there is poor evidence for an association between measures of brain morphology and of psychopathology symptoms/neurocognitive performance. Overall, numerous methodological issues characterize the literature to date. These include investigation of small sample sizes, heterogeneity across studies in sample characteristics (e.g., sex, comorbidity) and in employed imaging techniques, as well as the examination of only a limited number of brain regions. These factors make it difficult to draw firm conclusions from the existing findings. Nevertheless, this review supports the notion that regular cannabis use is associated with alterations of brain morphology, and highlights the need to consider particular methodological issues when planning future cannabis research.
authors.forename: Valentina
authors.initials: V
authors.lastname: Lorenzetti
authors.forename: Nadia
authors.initials: N
authors.lastname: Solowij
authors.forename: Alex
authors.initials: A
authors.lastname: Fornito
authors.forename: Dan Ian
authors.initials: DI
authors.lastname: Lubman
authors.affiliation: Monash Clinical and Imaging Neuroscience, School of psychology and Psychoatry, Monash University. 1st floor Monash Biomedical Imaging, 770 Blackburn road Clayton 3800 VIC, Australia. murat.yucel@monash.edu.
authors.forename: Murat
authors.initials: M
authors.lastname: Yucel
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000473:pathology; D002188:Cannabis / Q000633:toxicity*; D003071:Cognition / Q000187:drug effects; D013759:Dronabinol / Q000633:toxicity; D004644:Emotions / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male
chemical_list: D013759:Dronabinol