COMT Val158Met moderation of cannabis-induced psychosis: a momentary assessment study of ‘switching on’ hallucinations in the flow of daily life

Authors

  • C. Henquet,

    1. Department of Psychiatry and Neuropsychology, EURON, Maastricht University Medical Centre, South Limburg Mental Health Research and Teaching Network, Maastricht, the Netherlands
    2. Division Addiction Care, Mondriaan Zorggroep, South Limburg, the Netherlands
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  • A. Rosa,

    1. Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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  • P. Delespaul,

    1. Department of Psychiatry and Neuropsychology, EURON, Maastricht University Medical Centre, South Limburg Mental Health Research and Teaching Network, Maastricht, the Netherlands
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  • S. Papiol,

    1. Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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  • L. Faňanás,

    1. Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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  • J. Van Os,

    1. Department of Psychiatry and Neuropsychology, EURON, Maastricht University Medical Centre, South Limburg Mental Health Research and Teaching Network, Maastricht, the Netherlands
    2. NIHR Biomedical Research Centre, Institute of Psychiatry, Kings College London, London, UK
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  • I. Myin-Germeys

    1. Department of Psychiatry and Neuropsychology, EURON, Maastricht University Medical Centre, South Limburg Mental Health Research and Teaching Network, Maastricht, the Netherlands
    2. School of Psychological Sciences, University of Manchester, Manchester, UK
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C. Henquet, Department of Psychiatry and Neuropsychology, EURON, Maastricht University Medical Centre, South Limburg Mental Health Research and Teaching Network, PO BOX 616 (Vijverdal), 6200 MD Maastricht, the Netherlands.
E-mail: cecile.henquet@sp.unimaas.nl

Abstract

Objective:  A functional polymorphism in the catechol-o-methyltransferase gene (COMT Val158Met) may moderate the psychosis-inducing effects of cannabis. In order to extend this finding to dynamic effects in the flow of daily life, a momentary assessment study of psychotic symptoms in response to cannabis use was conducted.

Method:  The experience sampling technique was used to collect data on cannabis use and occurrence of symptoms in daily life in patients with a psychotic disorder (n = 31) and healthy controls (n = 25).

Results:  Carriers of the COMT Val158Met Val allele, but not subjects with the Met/Met genotype, showed an increase in hallucinations after cannabis exposure, conditional on prior evidence of psychometric psychosis liability.

Conclusion:  The findings confirm that in people with psychometric evidence of psychosis liability, COMT Val158Met genotype moderates the association between cannabis and psychotic phenomena in the flow of daily life.

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