Having used cannabis recreationally back in the late 1960s and early 1970s, I was interested when I started hearing over the past few years about its value as a medicine. And really interested and sort of amazed when my online research about medical cannabis demonstrated made me understand the broad range of illnesses that cannabis can treat through its main psychoactive cannabinoid, delta-9 tetrahydrocannabinol (THC), and its main non-psychoactive cannabinoid, cannabidiol (CBD), alone and together. I decided to write a book about medical cannabis.
As I later learned, all the other cannabinoids — 120 of them at last count — and terpenes, flavonoids, and another 400 constituents, most of which haven’t even been studied yet, add to the medical value of cannabis. The value is this: for the past 5,000 years, healers and physicians all over the world have been using cannabis in all its forms to treat patients who have anxiety, multiple sclerosis, irritable bowel syndrome, diabetes, addiction, chronic pain, stress. posttraumatic stress disorder, sleep disorders, and lots more.
Close-up of cannabis female plant in flowering phase. Shutterstock by noxnorthys.
I thought, How can it possibly do all that? Nothing does that.
That, and the rest of the story, were was full of surprises. During a couple of years of research, then in interviews with some of the best researchers in cannabinoid science, I learned how cannabis works in the brain and body, and why it works at all.
It works because of an ancient biological system, called the endocannabinoid system, the ECS, whose primordial elements arose in some of the earliest forms of life on Earth, 1 billion or 2 billion years ago. And the ECS evolved through time until about 590 million years ago, a time when its main elements had come together to form a complete endocannabinoid system in two non-vertebrate marine animals — the sea squirt and amphioxus (sea squirt shown).
Since then, and all the way up to now, the ECS has been in place in the bodies and brains of every vertebrate that swims or crawls or walks the planet — everything from fish to you and me.
Now, the primordial element of the ECS didn’t appear in bacteria a billion years ago just so Mother Nature could be sure that whoever smoked or ate cannabis billions of years in the future would get high. No. Flowering plants only arose within the past 100 million years or so, and cannabis itself evolved out into the world no earlier than about 34 million years ago.
Learning all this, I couldn’t believe how old everything was. As far as I was concerned, cannabis had its beginnings in 1966, at a high school in Neptune Beach, Florida.
Dr. Maurice Elphick. Photo by Dr. David Hone.
So during one of the interviews, this one with Dr. Maurice Elphick, a biologist and professor of physiology and neuroscience in the School of Biological and Chemical Sciences at Queen Mary University in London, I kept saying, “Wait — do you mean that elements of this system were in bacteria 1 billion years ago? A billion?” “Yes,” he kept saying patiently, “a billion. Or more.”
While I was getting my head around this I continued to interview researchers. One of them was Dr. Gregory Gerdeman, a neuroscientist and Chief Scientific Officer at Colorado-based United Cannabis. He explained the real purpose in the brain and body of the endocannabinoid system, the reason evolution had conserved the ECS and its elements across a billion years.
Gerdeman described how cells send signals to each other to coordinate all the biological systems and processes. A signal in one cell is electrochemically made to cross the gap between cells called a synapse. Once across, the signaling molecule attaches to a protein called a receptor on or under the surface of the next cell, delivering its message by changing the shape of the receptor. And during 100 years of this neuronal doctrine, everyone thought the flow of information across the synapses went one way. But over time, and after work by many researchers in the field, including Gerdeman, they realized that for the ECS, cell signaling went backward — from the postsynaptic cell backwards to the presynaptic cell.
Dr. Gregory Gerdeman. Courtesy photo.
Why? To modulate, or tone down, the signals coming across the synapse the old-fashioned way. The ECS signaling molecules, called endogenous cannabinoids, or endocannabinoids (cannabinoids made by the body itself) were the first really clear example of retrograde signaling, he said, and they were all over the brain.
“The ability of the brain to adapt and respond and learn on a cellular and circuit level is greatly enhanced if information can go the other way as well, and cells can adjust their own synaptic inputs simply by releasing some sort of feedback molecules,” he explained, “and the endocannabinoids act as feedback, but not just feedback.”
Gerdeman said the two main endocannabinoids and their retrograde signaling are part of the brain’s mechanism of resilience in response to trauma and electrical activity gone crazy, as in epileptic seizures, meaning that the ECS is a protective system for the body and brain, just like the immune system is protective against viruses and bacteria.
“We have an electrical organ of unimaginable complexity, in our case, and it can get turned up too high and cause damage. 
The endocannabinoid system evolved to turn that system down, scale it down, to protect it,” Gerdeman said. “And I’m rather convinced that the evolutionary emergence of the endocannabinoid system in this way was a necessary prerequisite for the evolution of the complex brains of vertebrates.”
And yet, most medical doctors know nothing about the ECS or the medical value of cannabis, and it’s not taught in medical schools.
And cannabis is illegal, at least where the feds are concerned, and this ultimately hampers the flow of reliable information. So HOW CANNABIS HEALS is for anyone who wants to know more about medical cannabis, anyone who thinks it might heal their illnesses, and anyone who wants a little help understanding this complex and little-known system that has evolved to protect us vertebrates from physical insults like strokes, other kinds of brain injuries, and much more.
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And for more about the endocannabinoid system, cannabis medicine and psychedelic medicine, please keep reading.
