Arizona’s new medical marijuana law makes it possible to prescribe cannabis for debilitating medical conditions that range from cancer, in amyotrophic lateral sclerosis (ALS), Crohn’s disease, the agitation of Alzheimer’s disease, and debilitating diseases or conditions that cause severe pain and disability. (I am eligible because of my chronic back pain the result of multiple back surgeries). But you can’t prescribe it for serious post-traumatic stress or chronic depression.

Research shows that THC (tetrahydrocannabinol), the psychoactive agent in marijuana), works at the same dopamine receptor sites that antidepressants do. They also work on a widespread group of receptors that are clustered not only in the brain but elsewhere in the body. These cannabinoids bind to the nervous system to set off reactions that reduce pain, anxiety, and provide a sense of well being.

Why does the body has these receptor sites? Surely not because it expects everybody to light up a joint one day, but because the body actually produces its own cannabinoids, called endocannabinoids (just like the bodies home-brewed opiates which we call endorphins). We used to think that endorphins were responsible for producing “runner’s high”; that sense of euphoria and calm that many people report feeling after prolonged exercise. Turns out that high has nothing to do with endorphins, because researchers have now found that the endorphins are large molecules which are unable to pass the blood brain barrier. Finding endorphins in the bloodstream after exercise can’t explain how the substance was having an effect on the mind.

In 2003, scientists at Georgia Tech found that 50 minutes of hard running on the treadmill or riding a stationary bicycle increased blood levels of endocannabinoids. It turns out that the euphoric, peaceful, elated, inner harmony that is “runners high” is just getting stoned from the inside.

I’d like to prescribe medical marijuana for patients with serious stress disorders and chronic depression because it can be effective and as safe as what’s currently being prescribed for these conditions.