Interaction Between Functional Genetic Variation of DRD2 and Cannabis Use on Risk of Psychosis.

Both cannabis use and the dopamine receptor (DRD2) gene have been associated with schizophrenia, psychosis-like experiences, and cognition. However, there are no published data investigating whether genetically determined variation in DRD2 dopaminergic signaling might play a role in individual susceptibility to cannabis-associated psychosis. We genotyped (1) a case-control study of 272 patients with their first episode of psychosis and 234 controls, and also from (2) a sample of 252 healthy subjects, for functional variation in DRD2, rs1076560.

High-potency cannabis and the risk of psychosis.

Background: People who use cannabis have an increased risk of psychosis, an effect attributed to the active ingredient Delta 9-tetrahydrocannabinol (Delta 9-THC). There has recently been concern over an increase in the concentration of Delta 9-THC in the cannabis available in many countries.

Aims: To investigate whether people with a first episode of psychosis were particularly likely to use high-potency cannabis.

What is the mechanism whereby cannabis use increases risk of psychosis?

Cannabis use has increased greatly over the last three decades. The various types of cannabis differ in their concentration of the main psychoactive component, Delta-9-tetrahydrocannabinol (THC), and the other major ingredient, cannabidiol (CBD). Plant engineering has maximized levels of THC, thus increasing the potency of street cannabis.

Catechol-O-methyltransferase (COMT) val158met genotype is associated with BOLD response as a function of task characteristic.

The catechol-O-methyltransferase (COMT) val(158)met single nucleotide polymorphism (rs4680) has been shown to be associated with brain activation during a number of neurocognitive and emotional tasks. The present study evaluated genotypic associations with brain function during measurement of cognitive stability (prosaccades) and plasticity (antisaccades). A total of 36 healthy volunteers were genotyped for rs4680 and underwent functional magnetic resonance imaging (fMRI) at 1.