A compound found in marijuana can treat schizophrenia as effectively as antipsychotic medications, with far fewer side effects, according to a preliminary clinical trial.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.
Antipsychotic medications can potentially cause devastating and sometimes permanent movement disorders; they can also reduce users’ motivation and pleasure. The new generation of antipsychotic drugs also often leads to weight gain and can increase diabetes risk. These side effects have long been known to be a major obstacle to treatment.In the German study, published online in March by the journal Translational Psychiatry, weight gain and movement problems were seen in patients taking amisulpride, but not CBD.
Nevertheless, the new research helps elucidate the intricate complexities of the brain’s natural cannabinoid system and how CBD may work to alleviate symptoms of schizophrenia. Years ago, Piomelli and his colleagues discovered that people with schizophrenia have elevated levels of anandamide — a neurotransmitter that activates the same receptor activated by THC — in their cerebrospinal fluid, suggesting that they also had higher levels of it in the brain.The difference was huge: anandamide levels were nine times higher in schizophrenic people than in mentally healthy controls, Piomelli says.
The new study confirmed that as CBD relieved patients’ symptoms, anandamide levels rose in concert. “It looks like anandamide is a signaling molecule that has evolved to help us cope with stress,” Piomelli says. “In the brain, everything it does seems to be related to ways of relieving stress. It can relieve anxiety and reduce the stress response. It is involved in stress-induced analgesia [when you stop feeling pain while fighting or fleeing].
Complicating matters further, when chronic marijuana smokers build up a tolerance to THC, it may down-regulate the entire system, making it harder for anandamide to have its positive effects. This may be why some studies find that people with schizophrenia who smoke marijuana get worse.So, where does CBD fit in? It doesn’t attach to a receptor like THC, or fool the brain into thinking that it’s getting extra anandamide or 2-AG. “What CBD seems to be doing is preventing anandamide from being destroyed,” says Piomelli. That allows the substance to exert its stress-reducing and antipsychotic effects on the brain longer, without the negative effects of THC.