Cannabis is still unfairly demonized around the world, and questionable newspapers like the Daily Mail sometimes even blame it for individual deaths. But science is getting more and more particular about a very crucial fact – that it is practically impossible to overdose on marijuana.
Whether or not you can overdose on cannabis depends on two things: how you ingest it and how you define the word “overdose.”
For most people talking about illicit drugs, an overdose means someone died or had to be resuscitated.
Basically, this is what we’ve seen with the growing opioid crisis: take too much and you die.
Depending on a person’s tolerance to cannabis, consuming marijuana could cause reactions like a racing heart, slower reaction times, nausea, and vomiting.
If you add health-related conditions into the mix, things get a little more dangerous. If someone has a pre-existing heart condition, for example, Dr. Chen (executive director of the UCLA Cannabis Research Initiative ) said cannabis could speed up their heart rate to the point they could have a heart attack.
But for a healthy person, the side effects that come with consuming marijuana, even in large quantities, aren’t enough to cause a life-threatening reaction.
Why Is Cannabis Overdose Usually Harmless?
In the brain, cannabis works by “binding” to a bunch of protein receptors and exerting effects on all kinds of physical functions, like mood, perception, appetite, and so on. If it wasn’t for those effects on mood and attitude, society probably wouldn’t value it so highly as a recreational drug!
As well as cannabis, other recreational drugs like cocaine, heroin, alcohol and barbiturates also work by binding to receptors in the brain. That’s what enables all these drugs to exert their weird and unusual effects on mood and perception.
So far, cannabis seems like any other recreational drug, right? But there is a crucial difference, and that is in the location of the protein receptors that cannabis binds to.
Heroin and cocaine are drugs that famously cause overdose, and that’s because the opioid and dopamine receptors that they bind to are present deep in the brainstem. The brainstem is the ancient part of the brain that controls basic bodily functions like breathing and the beating of the heart.
When the receptors in the brainstem get flooded with too much of a non-native compound, like heroin or cocaine, it can cause respiratory or cardiovascular failure. The foreign compounds cause the normal function to be drastically interrupted – resulting in a potentially lethal overdose.
But cannabis neatly sidesteps all of that. The cannabinoid receptors of the endocannabinoid system are very rarely located in the brainstem, so they do not have any control over essential functions like breathing and heartbeat.
This means we can essentially flood our brains with as much cannabis as it’s physically possible to consume, and it won’t affect the brain in ways that would make the lungs and the heart stop working, as is the case with an overdose of cocaine, heroin or even alcohol.
So while we can take too much cannabis and feel ill effects, it’s practically impossible for a human to overdose on cannabis lethally.
Sparse densities in lower brainstem areas controlling cardiovascular and respiratory functions may explain why high doses of delta 9-tetrahydrocannabinol are not lethal.