Researchers led by Markus Leweke of the University of Cologne in Germany studied 39 people with schizophrenia who were hospitalized for a psychotic episode. Nineteen patients were treated with amisulpride, an antipsychotic medication that is not approved in the U.S., but is comparable to other medications that are.
The rest of the patients were given cannabidiol (CBD), a substance found in marijuana that is thought to be responsible for some of its mellowing or anxiety-reducing effects. Unlike the main ingredient in marijuana, THC, which can produce psychotic reactions and may worsen schizophrenia, CBD has antipsychotic effects, according to previous research in both animals and humans.
Neither the patients nor the scientists knew who was getting which drug. At the end of the four-week trial, both groups showed significant clinical improvement in their schizophrenic symptoms, and there was no difference between those getting CBD or amisulpride.