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Schizophrenia Research and Treatment
Volume 2013, Article ID 543842, 10 pages
Clinical Study

The Neural Correlates of Mental Rotation Abilities in Cannabis-Abusing Patients with Schizophrenia: An fMRI Study

1Centre de Recherche de l’Institut Universitaire de Santé Mentale de Montréal, 7331 Hochelaga, Montreal, QC, Canada H1N 3V2
2Department of Psychiatry, Faculty of Medicine, University of Montreal, 2900 Edouard-Montpetit, Montreal, QC, Canada H3C 3J7
3Department of Psychiatry, Faculty of Medicine, University of Sherbrooke, 580 Bowen Sud, Sherbrooke, QC, Canada J1G 2E8
4Centre Hospitalier de l’Université de Montréal, 1058 St-Denis, Montreal, QC, Canada H2X 3J4
5Department of Physiology, Faculty of Medicine, University of Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, QC, Canada J1H 5N4
6Department of Psychology, Bishop’s University, 2600 College, Sherbrooke, QC, Canada J1M 1Z7

Received 19 April 2013; Revised 20 June 2013; Accepted 2 July 2013

Academic Editor: Robin Emsley

Copyright © 2013 Stéphane Potvin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Growing evidence suggests that cannabis abuse/dependence is paradoxically associated with better cognition in schizophrenia. Accordingly, we performed a functional magnetic resonance imaging (fMRI) study of visuospatial abilities in 14 schizophrenia patients with cannabis abuse (DD), 14 nonabusing schizophrenia patients (SCZ), and 21 healthy controls (HCs). Participants performed a mental rotation task while being scanned. There were no significant differences in the number of mistakes between schizophrenia groups, and both made more mistakes on the mental rotation task than HC. Relative to HC, SCZ had increased activations in the left thalamus, while DD patients had increased activations in the right supramarginal gyrus. In both cases, hyper-activations are likely to reflect compensatory efforts. In addition, SCZ patients had decreased activations in the left superior parietal gyrus compared to both HC and DD patients. This latter result tentatively suggests that the neurophysiologic processes underlying visuospatial abilities are partially preserved in DD, relative to SCZ patients, consistently with the findings showing that cannabis abuse in schizophrenia is associated with better cognitive functioning. Further fMRI studies are required to examine the neural correlates of other cognitive dysfunctions in schizophrenia patients with and without comorbid cannabis use disorder.