Marijuana refers to the dried leaves, flowers, stems, and seeds from the hemp plant, Cannabis sativa. Marijuana contains many substances, including over 100 in a group known as cannabinoids. Of these, delta-9-tetrahydrocannabinol (THC) is the most potent psychoactive chemical. It is the THC that provides for people the “high” that they seek recreationally. There are also medicinal uses of marijuana. For instance, it can reduce nausea and stimulate appetite, which are helpful for people with cancer who are undergoing chemotherapy. More recently, it has been shown that certain types of epilepsy unresponsive to standard treatments improve with marijuana. It is not clear which of the cannabinoid substances in marijuana function therapeutically. There are probably several. For instance, it is not THC that is responsible for the antiseizure (anticonvulsive) effects. The one being studied most for this purpose is cannabidilol. (CBD). Where it is allowed, CBD is sold as a tinctures or oils.
In order for a chemical substance to have an effect in the brain, it must find and attach itself to a structure known as a receptor. But why would the brain have receptors for marijuana cannabinoids? It turns out that the brain makes its own cannabinoid chemicals known as endocannabinoids. There are several cannabinoid receptors that are used by the body for various purposes, including CB1 and CB2. One of the most common endocannabinoids is anandamide. Anandamide seems to be important in reducing anxiety and depression. CBD mimics anandamide THC is much stronger than anandamide, and affects the brain very differently. It is psychoactive and can produce a variety of cognitive and behavioral alterations, including psychosis.
It is undeniable that marijuana can produce psychosis in otherwise healthy people. THC in particular can alter brain development, especially in young people. CB1 and CB2 receptors occur throughout the brain and body, which would help account for the diverse effects that marijuana has physically and psychologically. Psychological effects include:
When these things become severe enough, psychosis can result. Many of these symptoms overlap with schizophrenia, but are not necessarily true schizophrenia. For biologically vulnerable people, there are indications that marijuana can trigger true schizophrenia or make it appear earlier in life. Heavy use of marijuana early in life is more likely to precipitate schizophrenia than usage later in life. So, it seems that, although marijuana can produce psychosis acutely upon usage, this does not guarantee that it will progress to schizophrenia unless there is a genetic predisposition to contract it. Schizophrenia affects 1-2 percent of the people, and normally shows up in late teens or early twenties.
Blog posts are written by Shore House members and staff.