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The Pharmaco-genetic and Brain Mechanisms Associated With Cannabis- Induced Psychosis

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01565174
Recruitment Status : Unknown
Verified April 2012 by VEINSHTEIN AVIV, Hadassah Medical Organization.
Recruitment status was:  Not yet recruiting
First Posted : March 28, 2012
Last Update Posted : April 3, 2012
Information provided by (Responsible Party):
VEINSHTEIN AVIV, Hadassah Medical Organization

Brief Summary:
There is growing evidence of high rates of substance use disorders among individuals with psychotic disorders especially in young people with predisposition for psychosis. There is some genetic evidence that carriers of the valine158 allele of the catechol-O-methyltransferase (COMT) gene had increased risk to exhibit psychotic symptoms and to develop schizophrenia if they used cannabis by the age of 18. It was also shown that carriers of the COMT val/val genotype were most sensitive to THC-induced psychotic experiences but this was conditional on pre-existing susceptibility to psychosis. The investigators propose to use brain-imaging and molecular genetics to investigate whether genetic factors may contribute to the THC-induced dopamine release and possibly to cannabis- induced psychosis.

Condition or disease
Cannabis Dependence Psychosis

Detailed Description:
Genetic association study will be performed in 100 young cannabis users (age 18-26 years) for genes that are related to the neurotransmitters dopamine (D2, DAT, COMT), GABA, glutamate and the cannabinoid receptor CB1. Out of this cohort, 24 male subjects without history of cannabis or drug-induced psychosis will undergo brain imaging procedure in order to measure THC-induced dopamine release using [11C] Raclopride in PET imaging. Carriers of high activity COMT158Val allele are expected to show higher meso-limbic DA release than carriers of low activity COMT 158Met homozygotes and after smoking a cigarette with THC which in turn are thought to underlie the risk for THC-induced psychotic symptoms. The aim of the present study is to evaluate the relationship between the COMT genotype and cannabis-induced meso-limbic dopamine release as measured by D2 occupancy. In addition, the association between predisposition to psychosis, age of onset of cannabis dependence, and genotype of COMT and other neurotransmitters-related genes will be evaluated. Such finding could provide novel pharmaco-genetic explanation for the psychogenic effects of cannabis in vulnerable individuals.

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Study Type : Observational
Estimated Enrollment : 100 participants
Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: The Pharmaco-genetic and Brain Mechanisms Associated With Cannabis- Induced Psychosis
Study Start Date : October 2012
Estimated Primary Completion Date : October 2014
Estimated Study Completion Date : October 2014

Resource links provided by the National Library of Medicine

High activity COMT
Carriers of high activity COMT158Val allele who are expected to show higher THC-induced meso-limbic DA release
Low activity COMT
Carriers of low activity COMT 158Met homozygotes are expected to release low amount of dopamine after smoking a cigarette with THC

Primary Outcome Measures :
  1. Genetic variations of Dopamine, GABA, glutamate, cannabis CB1 receptor [ Time Frame: 2 years ]
    DNA will be extracted from saliva of participants. Genetic variations of DA, GABA, glutamate and cannabis receptor CB1 will be coded.

Secondary Outcome Measures :
  1. Measures of dopamine D2 receptor occupancy before and after smoking a cigarette containing THC. [ Time Frame: 2 years ]
    Participants will be studied in a brain imaging study using [C 11] raclopride radioligand in Positron Emission Tomography (PET). Measures of D2 receptor occupancy will be taken at baseline and after smoking a cigarette containing 15 mg THC.

Biospecimen Retention:   Samples With DNA
Samples of DNA will be taken from saliva of participants

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 26 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
100 current users of cannabis

Inclusion Criteria:

  • age 18-26 meeting DSM-IV-TR (American Psychiatric Association, 1994) diagnosis of THC dependence will be recruited from the general population by advertisement in the newspapers.

Exclusion Criteria:

  • dependence on other substances or alcoholism
  • a history of CNS disease
  • a history of infection that might affect CNS (HIV, syphilis, cytomegalovirus, herpes)
  • a history of head injury with loss of consciousness and pregnancy

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01565174

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Contact: Aviv M Weinstein, Ph.D 972-2-6776705
Contact: Roland Chisin, M.D 972-2-6776705

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Hadassah Medical Organization, Jerusalem, Israel
Jerusalem, Israel, 91120
Contact: Hadas Lemberg, Ph.D    00 972 2 6777572   
Principal Investigator: Aviv M Weinstein, Ph.D         
Sponsors and Collaborators
Hadassah Medical Organization
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Principal Investigator: Aviv Weinstein, Ph.D Hadassah Medical Organization
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Responsible Party: VEINSHTEIN AVIV, Senior Research Fellow, Hadassah Medical Organization Identifier: NCT01565174    
Other Study ID Numbers: 0541-11-HMO-CTIL
First Posted: March 28, 2012    Key Record Dates
Last Update Posted: April 3, 2012
Last Verified: April 2012
Keywords provided by VEINSHTEIN AVIV, Hadassah Medical Organization:
Additional relevant MeSH terms:
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Marijuana Abuse
Psychotic Disorders
Mental Disorders
Shared Paranoid Disorder
Schizophrenia Spectrum and Other Psychotic Disorders
Substance-Related Disorders
Chemically-Induced Disorders