Cerebellar white-matter changes in cannabis users with and without schizophrenia

• Published in: Psychological medicine Vol. 41; no. 11; pp. 2349 - 2359
• Main Authors: Solowij, N., Yücel, M., Respondek, C., Whittle, S., Lindsay, E., Pantelis, C., Lubman, D. I.
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.11.2011
• Subjects: Adult; Adult and adolescent clinical studies; Analysis of covariance; Australia - epidemiology; Biological and medical sciences; Brain; Cannabis; Case-Control Studies; Cerebellum; Cerebellum - growth & development; Cerebellum - pathology; Chronic Disease; Comorbidity; Drug use; Genes; Humans; Long term; Magnetic Resonance Imaging; Male; Marijuana; Marijuana Abuse - epidemiology; Marijuana Abuse - pathology; Medical sciences; Middle Aged; Neuropathology; Organ Size; Psychology. Psychoanalysis. Psychiatry; Psychopathology. Psychiatry; Psychoses; Psychosis; Psychotic symptoms; Schizophrenia; Schizophrenia - epidemiology; Schizophrenia - pathology; Australia; structural magnetic resonance imaging; Cannabis; schizophrenia; cerebellum; Cerebellum; Central nervous system; Schizophrenia; Cannabidaceae; Nuclear magnetic resonance imaging; White matter; Encephalon; Psychosis; Dicotyledones; Angiospermae; Medical imagery; Spermatophyta; Drug of abuse; Comparative study; Recreational drug
• ISSN: 0033-2917; 1469-8978; 1469-8978
• DOI: 10.1017/S003329171100050X

The cerebellum is rich in cannabinoid receptors and implicated in the neuropathology of schizophrenia. Long-term cannabis use is associated with functional and structural brain changes similar to those evident in schizophrenia, yet its impact on cerebellar structure has not been determined. We examined cerebellar grey and white matter in cannabis users with and without schizophrenia. Seventeen patients with schizophrenia and 31 healthy controls were recruited; 48% of the healthy group and 47% of the patients were long-term heavy cannabis users (mean 19.7 and 17.9 years near daily use respectively). Cerebellar measures were extracted from structural 3-T magnetic resonance imaging (MRI) scans using semi-automated methods, and examined using analysis of covariance (ANCOVA) and correlational analyses. Cerebellar white-matter volume was reduced in cannabis users with and without schizophrenia compared to healthy non-users, by 29.7% and 23.9% respectively, and by 17.7% in patients without cannabis use. Healthy cannabis users did not differ in white-matter volume from either of the schizophrenia groups. There were no group differences in cerebellar grey matter or total volumes. Total cerebellar volume decreased as a function of duration of cannabis use in the healthy users. Psychotic symptoms and illness duration correlated with cerebellar measures differentially between patients with and without cannabis use. Long-term heavy cannabis use in healthy individuals is associated with smaller cerebellar white-matter volume similar to that observed in schizophrenia. Reduced volumes were even more pronounced in patients with schizophrenia who use cannabis. Cannabis use may alter the course of brain maturational processes associated with schizophrenia.