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Watts JJ, Jacobson MR, Lalang N, Boileau I, Tyndale RF, Kiang M, Ross RA, Houle S, Wilson AA, Rusjan P, Mizrahi R. Imaging Brain Fatty Acid Amide Hydrolase in Untreated Patients With Psychosis. Biol Psychiatry 2020; 88:727-735. [PMID: 32387132 PMCID: PMC8240477 DOI: 10.1016/j.biopsych.2020.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 03/01/2020] [Accepted: 03/04/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND The brain's endocannabinoid system, the primary target of cannabis, has been implicated in psychosis. The endocannabinoid anandamide is elevated in cerebrospinal fluid of patients with schizophrenia. Fatty acid amide hydrolase (FAAH) controls brain anandamide levels; however, it is unknown if FAAH is altered in vivo in psychosis or related to positive psychotic symptoms. METHODS Twenty-seven patients with schizophrenia spectrum disorders and 36 healthy control subjects completed high-resolution positron emission tomography scans with the novel FAAH radioligand [11C]CURB and structural magnetic resonance imaging. Data were analyzed using the validated irreversible 2-tissue compartment model with a metabolite-corrected arterial input function. RESULTS FAAH did not differ significantly between patients with psychotic disorders and healthy control subjects (F1,62.85 = 0.48, p = .49). In contrast, lower FAAH predicted greater positive psychotic symptom severity, with the strongest effect observed for the positive symptom dimension, which includes suspiciousness, delusions, unusual thought content, and hallucinations (F1,26.69 = 12.42, p = .002; Cohen's f = 0.42, large effect). Shorter duration of illness (F1,26.95 = 13.78, p = .001; Cohen's f = 0.39, medium to large effect) and duration of untreated psychosis predicted lower FAAH (F1,26.95 = 6.03, p = .021, Cohen's f = 0.27, medium effect). These results were not explained by past cannabis exposure or current intake of antipsychotic medications. FAAH exhibited marked differences across brain regions (F7,112.62 = 175.85, p < 1 × 10-56; Cohen's f > 1). Overall, FAAH was higher in female subjects than in male subjects (F1,62.84 = 10.05, p = .002; Cohen's f = 0.37). CONCLUSIONS This first study of brain FAAH in psychosis indicates that FAAH may represent a biomarker of disease state of potential utility for clinical studies targeting psychotic symptoms or as a novel target for interventions to treat psychotic symptoms.
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Affiliation(s)
- Jeremy J Watts
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Maya R Jacobson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Nittha Lalang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Isabelle Boileau
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Rachel F Tyndale
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Ruth A Ross
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Sylvain Houle
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Alan A Wilson
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Pablo Rusjan
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada.
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Watts JJ, Garani R, Da Silva T, Lalang N, Chavez S, Mizrahi R. Evidence That Cannabis Exposure, Abuse, and Dependence Are Related to Glutamate Metabolism and Glial Function in the Anterior Cingulate Cortex: A 1H-Magnetic Resonance Spectroscopy Study. Front Psychiatry 2020; 11:764. [PMID: 32973572 PMCID: PMC7468488 DOI: 10.3389/fpsyt.2020.00764] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/20/2020] [Indexed: 02/06/2023] Open
Abstract
There is evidence that long-term cannabis use is associated with alterations to glutamate neurotransmission and glial function. In this study, 26 long-term cannabis users (males=65.4%) and 47 non-cannabis using healthy controls (males=44.6%) underwent proton magnetic resonance spectroscopy (1H-MRS) of the anterior cingulate cortex (ACC) in order to characterize neurometabolite alterations in cannabis users and to examine associations between neurometabolites, cannabis exposure, and cannabis use behaviors. Myo-inositol, a marker of glial function, and glutamate metabolites did not differ between healthy controls and cannabis users or cannabis users who met criteria for DSM5 cannabis use disorder (n=17). Lower myo-inositol, a putative marker of glial function, was related to greater problematic drug use (F1,22 = 11.95, p=.002; Cohen's f=0.59, large effect; Drug Abuse Screening Test) and severity of cannabis dependence (F1,22 = 6.61, p=.17; Cohen's f=0.44, large effect). Further, past-year cannabis exposure exerted different effects on glutamate and glutamate+glutamine in males and females (glutamate: F1,21 = 6.31, p=.02; glutamate+glutamine: F1,21 = 7.20, p=.014), such that greater past-year cannabis exposure was related to higher concentrations of glutamate metabolites in male cannabis users (glutamate: F1,14 = 25.94, p=.00016; Cohen's f=1.32, large effect; glutamate+glutamine: F1,14 = 23.24, p=.00027, Cohen's f=1.24, large effect) but not in female cannabis users (glutamate: F1,6 = 1.37, p=0.78; glutamate+glutamine: F1,6 = 0.001, p=.97). The present results extend existing evidence of altered glial function and glutamate metabolism with cannabis use by providing evidence linking problematic drug use behaviors with glial function as measured with myo-inositol and recent chronic cannabis exposure to alterations in glutamate metabolism. This provides novel directions for the interrogation of the impact of cannabis use on brain neurochemistry.
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Affiliation(s)
- Jeremy J Watts
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON, Canada
| | - Ranjini Garani
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON, Canada
| | - Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Nittha Lalang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON, Canada
| | - Sofia Chavez
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
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