Clinical trial NCT01565174: The Pharmaco-genetic and Brain Mechanisms Associated With Cannabis- Induced Psychosis
Official title: The Pharmaco-genetic and Brain Mechanisms Associated With Cannabis- Induced Psychosis
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Cannabis Dependence
Psychosis
Keywords: cannabis
THC
COMT
psychosis
D2
Lead sponsor: Hadassah Medical Organization
Sponsor class: OTHER
First posted: 2012-03-28
Enrollment: 100
Sex: MALE
Minimum age (years): 18
Maximum age (years): 26
Standard ages: ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: CROSS_SECTIONAL
Sampling method: NON_PROBABILITY_SAMPLE
Study population: 100 current users of cannabis

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.

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.

Eligibility criteria: 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

Primary outcomes:
measure: Genetic variations of Dopamine, GABA, glutamate, cannabis CB1 receptor
timeFrame: 2 years
Secondary outcomes:
measure: Measures of dopamine D2 receptor occupancy before and after smoking a cigarette containing THC.
timeFrame: 2 years
Other outcomes:
Locations:
city: Jerusalem
country: Israel
facility: Hadassah Medical Organization, Jerusalem, Israel
Study officials:
affiliation: Hadassah Medical Organization
name: Aviv Weinstein, Ph.D
role: PRINCIPAL_INVESTIGATOR
References: