Use of marijuana is associated with psychosis

 Psychosis is a severe mental disorder that affects thought and emotions which leads to impaired contact with external reality.

Ingredients in marijuana have opposite effects on human brain, tetrahydrocannabinol THC, increases the brain processes that can lead to symptoms of psychosis.

Marijuana users may experience psychosis because THC interferes with the brain's ability to distinguish between stimuli that are important, and those that are not.

Psychotic symptoms have been linked to abnormal salience attribution, meaning that the brain has difficulty telling the difference between stimuli that are important and those that are not.

Functional magnetic resonance imaging (fMRI) scans was used to observe participants brains after they took pills containing THC. The images showed changes in the areas of the brain that linked to symptoms of psychosis.

Taking THC increased the activity in the prefrontal cortex, but lower activity in the striatum because THC alters the brain's levels of the neurotransmitter dopamine.
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