- Title
- Functional magnetic resonance brain imaging of executive cognitive performance in young first-episode schizophrenia patients and age-matched long-term cannabis users
- Creator
- Cohen, Martin; Johnston, Patrick; Ehlkes, Tim; Fulham, Ross; Ward, Philip; Thienel, Renate; Rasser, Paul; Carr, Vaughan; Baker, Amanda; Schall, Ulrich
- Relation
- NHMRC.300734
- Relation
- Neurology Psychiatry and Brain Research Vol. 21, Issue 1, p. 51-63
- Publisher Link
- http://dx.doi.org/10.1016/j.npbr.2014.09.002
- Publisher
- Elsevier
- Resource Type
- journal article
- Date
- 2015
- Description
- Converging evidence from epidemiological, clinical and neuropsychological research suggests a link between cannabis use and increased risk of psychosis. Long-term cannabis use has also been related to deficit-like "negative" symptoms and cognitive impairment that resemble some of the clinical and cognitive features of schizophrenia. The current functional brain imaging study investigated the impact of a history of heavy cannabis use on impaired executive function in first-episode schizophrenia patients. Whilst performing the Tower of London task in a magnetic resonance imaging scanner, event-related blood oxygenation level-dependent (BOLD) brain activation was compared between four age and gender-matched groups: 12 first-episode schizophrenia patients; 17 long-term cannabis users; seven cannabis using first-episode schizophrenia patients; and 17 healthy control subjects. BOLD activation was assessed as a function of increasing task difficulty within and between groups as well as the main effects of cannabis use and the diagnosis of schizophrenia. Cannabis users and non-drug using first-episode schizophrenia patients exhibited equivalently reduced dorsolateral prefrontal activation in response to task difficulty. A trend towards additional prefrontal and left superior parietal cortical activation deficits was observed in cannabis-using first-episode schizophrenia patients while a history of cannabis use accounted for increased activation in the visual cortex. Cannabis users and schizophrenia patients fail to adequately activate the dorsolateral prefrontal cortex, thus pointing to a common working memory impairment which is particularly evident in cannabis-using first-episode schizophrenia patients. A history of heavy cannabis use, on the other hand, accounted for increased primary visual processing, suggesting compensatory imagery processing of the task.
- Subject
- schizophrenia; cannabis use; co-morbidity; functional brain imaging; executive function; Tower of London
- Identifier
- http://hdl.handle.net/1959.13/1332512
- Identifier
- uon:26883
- Identifier
- ISSN:0941-9500
- Language
- eng
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