Answer A: After smoking a joint - or eating a brownie - our good buddy, Delta-9-tetrahydrocannabinol (aka THC), does his magic. Once THC hits the bloodstream, it ignites a euphoric body buzz that consumes you with feelings of tranquility, well-being and (sometimes) an uncontrollable case of the giggles.
Answer B: It's all about dopamine! That's why they called it "dope." Dopamine is tied to the reward circuitry in our brain. When you consume cannabis, it sends a signal to your brain to produce more dopamine, which in turn makes you feel good!
The first answer is accurate, but is only a partial explanation. THC is the primary psychoactive chemical that triggers the effects, but there's more to it. The second answer, it turns out, is less fact, and more fiction.
No doubt, if there were ever a neurotransmitter that was a celebrity, it would be dopamine! Few molecules have been associated with pleasure more than dopamine. In the media, it's been characterized as the bad boy of molecules; the Kim Kardashian of compounds; the molecule your mother warned you about! Supposedly all drugs (and many activities) share dopamine as the unifying underlying factor that explains their appeal - and, why people want to repeat the behavior.
There may be something to be said about this explanation when it comes to stimulants, which in fact, do cause your brain to produce a crazy amount of dopamine. But, when it comes to cannabis, the explanation doesn't hold up to further scrutiny. There's little evidence to suggest ingesting cannabis causes your brain to produce an appreciable amount of dopamine - at least in humans. Rats, yes. Humans, not so much. Researchers at King's College London reviewed every published study on humans, and concluded: “In man, there is as yet little direct evidence to suggest that cannabis use affects acute striatal dopamine release or affects chronic dopamine receptor status in healthy human volunteers."
(On a side note, the link between dopamine and the slang term, "dope", is purely coincidental.)
Meet Man's "Bliss Molecule," Anandamide
Meet, anandamide. In the early 1990s, Dr. Raphael Mechoulam (the man who discovered THC) and his team (including Czech analytical chemist Lumír Ondřej Hanuš and American molecular pharmacologist, William Anthony Devane) discovered a neurotransmitter called anandamide. Anandamide is a naturally occurring version of THC that can produce a heightened sense of joy and happiness (and a lot more); it's been described as the “bliss molecule." In fact, the term, anandamide, comes from the Sanskrit word “ananda," which means "joy" or "bliss."
Your body naturally produces anandamide. Likewise, eating chocolate, doing yoga and jogging, have all been found to stimulate anandamide production. You've heard of the "runner's high?" It's anandamide (not endorphins). So, if our body naturally produces anandamide, why aren't we always "high?" Anandamide breaks down in the body quickly, hence, why it doesn't create a perpetual state of bliss. And, likely why chocolate or running, doesn't produce as intense of a high as cannabis.
Essentially, THC is the mimetic twin of anandamide, meaning it acts a lot like anandamide. Because they share similar properties, they behave in similar ways. When you smoke cannabis, Delta-9-THC binds to your CB1 receptors, activating the psychoactive effects. You'll usually feel the effects in a few seconds, peaking in about 30 minutes, and tapering off within a few hours.
When you consume an edible, the effects can take anywhere from 30 to 90 minutes. However, when Delta-9-THC travels through the stomach to the liver, it is converted into 11-Hydroxy-THC - which is actually much more psychoactive than Delta-9-THC. This explains why edibles - despite less bioavailability - can be more potent and the effects last longer; and, why an edible containing 10mg of THC can produce a high similar to smoking a joint containing much higher amounts of THC. There are some pre-rolls advertising 500mg - even 750mg of THC. If you ate that much THC, unless you have a ridiculously high tolerance, you'd be couch-locked until the next installment of "Harold & Kumar" comes out!
Circling back around to the anandamide and THC connection, author Terry Necco who wrote the seminal book, "Marijuana and Sex: A Classic Combination," explains it in a nutshell:
"Just as our bodies contain pleasure systems which reward us for sex; our brains contain neurocellular circuitry which can only be activated by substances with THC's molecular structure. This makes the marijuana high a unique constellation of feelings, and there are only two sources for the substances which activate THC's very own neuroreceptor. Our brain is one source: it generates a neurochemical very similar to THC, called anandamide...The only other source for this bliss-producing substance is the cannabis plant."