3 results
Cerebellar white-matter changes in cannabis users with and without schizophrenia
- N. Solowij, M. Yücel, C. Respondek, S. Whittle, E. Lindsay, C. Pantelis, D. I. Lubman
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- Journal:
- Psychological Medicine / Volume 41 / Issue 11 / November 2011
- Published online by Cambridge University Press:
- 05 April 2011, pp. 2349-2359
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Background
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.
MethodSeventeen 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.
ResultsCerebellar 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.
ConclusionsLong-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.
Contributors
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- By Nicholas B. Allen, Stephanie Assuras, Robert M. Bilder, Joan C. Borod, John L. Bradshaw, Warrick J. Brewer, Ariel Brown, Nik Brown, Tyrone Cannon, Audrey Carstensen, Cameron S. Carter, Luke Clark, Phyllis Chua, Thilo Deckersbach, Richard A. Depue, Tali Ditman, Aleksey Dumer, David E. Fleck, Lara Foland-Ross, Judith M. Ford, Nelson Freimer, Paolo Fusar-Poli, Nathan A. Gates, Terry E. Goldberg, George Graham, Igor Grant, Melissa J. Green, Michelle M. Halfacre, Wendy Heller, John D. Herrington, Garry D. Honey, Jennifer E. Iudicello, Henry J. Jackson, J. David Jentsch, Donald Kalar, Paul Keedwell, Ester Klimkeit, Nancy S. Koven, Donna A. Kreher, Gina R. Kuperberg, Edythe London, Dan I. Lubman, Daniel H. Mathalon, Patrick D. McGorry, Philip McGuire, George R. Mangun, Gregory A. Miller, Albert Newen, Jack B. Nitschke, Jaak Panksepp, Christos Pantelis, Mary Philips, Russell A. Poldrack, Scott L. Rauch, Susan M. Ravizza, Steven Paul Reise, Nicole Rinehart, Angela Rizk-Jackson, Trevor W. Robbins, Tamara A. Russell, Fred W. Sabb, Cary R. Savage, Kimberley R. Savage, J. Cobb Scott, Marc L. Seal, Larry J. Seidman, Paula K. Shear, Marisa M. Silveri, Nadia Solowij, Laura Southgate, G. Lynn Stephens, D. Stott Parker, Stephen M. Strakowski, Simon A. Surguladze, Kate Tchanturia, René Testa, Janet Treasure, Eve M. Valera, Kai Vogeley, Anthony P. Weiss, Sarah Whittle, Stephen J. Wood, Steven Paul Woods, Murat Yücel, Deborah A. Yurgelun-Todd
- Edited by Stephen J. Wood, University of Melbourne, Nicholas B. Allen, University of Melbourne, Christos Pantelis, University of Melbourne
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- Book:
- The Neuropsychology of Mental Illness
- Published online:
- 10 May 2010
- Print publication:
- 01 October 2009, pp xv-xx
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Attentional bias for drug cues in opiate dependence
- D. I. LUBMAN, L. A. PETERS, K. MOGG, B. P. BRADLEY, J. F. W. DEAKIN
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- Journal:
- Psychological Medicine / Volume 30 / Issue 1 / January 2000
- Published online by Cambridge University Press:
- 01 January 2000, pp. 169-175
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Background. In a number of theories of compulsive drug use conditioned responses to stimuli associated with drug taking play a pivotal role. For example, according to incentive-sensitization theory (Robinson & Berridge, 1993), drug-related stimuli selectively capture attention, and the neural mechanisms underlying this attentional bias play a key role in the development and maintenance of drug dependence, and in relapse. However, there has been little work that assesses attentional biases in addiction.
Methods. We used a pictorial probe detection task to investigate whether there is an attentional bias to stimuli associated with drug use in opiate dependence. Stimuli presented included pairs of drug-related and matched neutral pictures. Methadone-maintained opiate addicts (N = 16) were compared with age-matched controls (N = 16).
Results. A mixed design analysis of variance of response times to probes revealed a significant three-way interaction of group×drug picture location×probe location. Opiate addicts had relatively faster reaction times to probes that replaced drug pictures rather than neutral pictures, consistent with the predicted attentional bias to drug-related stimuli.
Conclusions. These results support the idea that an attentional bias for drug-related stimuli occurs in opiate dependence. This is consistent with the concept of a central role for such salient stimuli in compulsive drug use.