Marijuana is the common name for a few plants in the cannabis genus including sativa, indica, and ruderalis used for its psychoactive properties around the world. Marijuana has also been traditionally used to treat inflammatory disorders.
Today, marijuana is used as an adjuvant cancer therapy, meaning it is used alongside other drugs that treat cancer. Medical marijuana use can alleviate pain and increase appetite. It is also being investigated for its effect on inflammation and chronic disorders like rheumatoid arthritis.
Inhaling marijuana smoke increases diastolic blood pressure and heart rate, though this change is temporary. However, there are many case studies that note marijuana usage 30 – 60 minutes before heart attacks. Heart attacks can occur when people with an elevated risk for heart disease push their blood pressure and heart rate to dangerous levels. Marijuana may also interact with some pharmaceuticals, which could result in elevated blood pressure and a heart attack. Smoking marijuana has also been associated with bronchitis.
Marijuana and Δ9THC, or delta-9 tetrahydrocannabinol, are well researched because they act on the cannabinergic system in the body, which is actually named after the plant. This system is regulated by two receptors, called cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 2 (CB2). CB1 is responsible for most of the psychoactive effects of marijuana, and CB2 is responsible for many of the long-term benefits marijuana may provide for inflammation and related diseases.
Marijuana usage over a long period of time can cause tolerance, and subsequently withdrawal. Marijuana withdrawal is recognized by the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). On a molecular level, marijuana tolerance occurs when the CB1 receptor is overstimulated and internalized, meaning absorbed by the cell. The CB1 receptor and the N-methyl-D-aspartate receptor (NMDA) receptor are linked when it comes to marijuana, so when CB1 signaling is inhibited, NMDA signaling is also hampered. This causes marijuana to be less effective for treating epilepsy and schizophrenia, though it also reduces the memory loss associated with marijuana use. Tolerance does not significantly affect the CB2 receptor, so marijuana may be effective for inflammatory disorders over a longer period of time.
Finally, high cannabidiol (CBD) products tend to be considered much different for therapeutic effects than are high Δ9THC products. Due to acting primarily on calcium channels known as TRPs, cannabidiol and other nonpsychoactive cannabinoids are thought to have therapeutic uses in the realms that Δ9THC fails (childhood epilepsy being the major one). While human evidence is lacking at the moment, there does appear to be reasonable evidence to suggest fairly potent therapeutic effects with high cannabidiol products.