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This Is How Science Explains Your High

Illustrations by Mark Nerys  

In your BODY

Dry mouth wasn’t well understood until 2006, when Argentine scientists working with rats discovered salivary glands actually contain cannabinoid receptors. THC inhibits the glands’ response time, slowing secretion of spit. Chronic use can create dental problems; otherwise, you’re just talking a dry tongue and thirst.
*That’s cotton mouth.

Bloodshot Eyes
Pot lowers blood pressure; in the eyes, capillaries widen and blood fills the void unless stopped by a vasoconstrictor like Visine. Also, intraocular pressure eases by as much as 30 percent—a welcome (though brief) drop, if you’ve got glaucoma. In some people, pupils dilate, too, which makes smokers shrink from bright lights and seriously complicates their ability to focus on nearby objects.

A normal heart rate of 60 to 100 beats per minute can climb to 160 in just ten minutes, and stay elevated for two, even three hours, though frequent use lessens the effect. Mostly, this just sounds scary: Palpitations and dizziness are all healthy smokers have to fear, though heart attacks and stroke have been reported in isolated cases.
*That’s a rapid heartbeat.

Cannabidiol, pot’s other major psychoactive cannabinoid, is much less understood than THC, but large amounts seem to moderate or improve sleep. THC, meanwhile, disrupts sleep patterns; a standard joint can screw with rem and stage-four sleep for up to five days.

The Munchies
Pot triggers the hypothalamus to release ghrelin, a hormone that stimulates hunger, but curtail leptin, the one that signals to the body “You’re full.” The latest research (admittedly, it’s on mice) suggests the effect might be primarily olfactory—marijuana makes food taste better simply by heightening the sense of smell.

In addition to THC, there are nearly a hundred other psychoactive chemicals present in pot. Very few cannabinoids have been studied in any detail. But the proportions of these are what separates the “trippiness” of one strain, like White Widow, from the “perma-grin” of another, like Blueberry Haze.

In your BRAIN

1. Brain Stem
This region, charged with autonomic functions like breathing and heart rate, is practically devoid of cannabinoid receptors—which is why virtually no one fatally overdoses on pot.

2. Basal Ganglia
A ball of several structures that controls many of the brain’s reward systems. This is the part of the brain that really makes you feel high (thanks in particular to the nucleus accumbens).

3. Amygdala
The thing that guides the mind toward suitable emotional responses; in smokers, it’s also responsible for paranoia and anxiety.

4. Hypothalamus
The brain’s appetite regulator and biological-clock setter, bursting with cannabinoid receptors. This almond-size region is what stoners can thank for time warp and the munchies.

5. Hippocampus
A squiggle down in the medial temporal lobe Über-rich in cannabinoid receptors and critical for memory-making; here, pot’s effects mimic a temporary brain lesion, which is why smokers can’t recall so much of their high.

6. Cerebellum
The nexus of motor control, especially coordination and timing. Both become sluggish under the effects of cannabis.

In your MIND, man

The marijuana-iest of the mental effects, this can be induced by smoking as little as 1.1 milligrams of THC, a fraction of a typical joint, and is basically the drug kicking the brain’s reward circuit into overdrive—the same process that intensifies things like eating and sex.

Literally the opposite effect. The fear can be so acute that users imagine themselves spiraling toward imminent death, but that’s an extreme. What aren’t extreme are anxiety and paranoia, reported by 40 percent and 50 percent of users, respectively. Nobody quite understands why. Pot might exacerbate depression or anxiety disorders in people already suffering from them, but for everybody else, some doctors suggest it might just be how they cope with startling somatic effects like a rising heart rate.

Distortion perception
THC induces a state of absorption, which can make music grow vivid, emotions get grander, and self-awareness nose-dive. Paradoxically, odd things don’t seem quite as odd, yet, thanks to an overstimulated amygdala, utterly mundane items acquire riveting novelty. There’s also something called audio “looping” (a noise heard over and over, for reasons not understood). As many as one-fifth of users experience visual hallucinations, again for reasons largely unknown. It could be the release of dopamine, which at high enough levels is associated with hallucinations.

Time lag
Because THC speeds up internal clocks, almost every stoned person overestimates how much time has passed while high. The drug seems to mess with the suprachiasmatic nucleus in the hypothalamus, disrupting its ability to sync with light, so users end up on their own in measuring time.

Memory impairment
As everyone who has smoked pot knows, it screws up your short-term memory (it also interferes with long-term formation). How? Basically: Some neurons tell other, agitated neurons to be quiet (this happens at a small scale all the time, but when high, the “be quiet” signal overwhelms). Interestingly, cannabidiol has been shown to mitigate the effect.

So Maybe It's Been a While ... But Here’s How Pot Works
Things have changed.

1. A flying start: Seconds after inhalation, smoke (full of over 100 chemical compounds called cannabinoids) is absorbed by the lungs, hitches a ride in the bloodstream, and makes for other tissues.

2. A few seconds later, the first delta-9-tetrahydro-cannabinol—that’s pot’s trippy, bad-boy THC—crosses the blood-brain barrier by expertly impersonating a neurotransmitter (anandamide) that helps regulate mood, memory, emotions, and appetite.

3. By 15 to 30 minutes in, mood-altering effects start to peak; they’ll last two to three hours, depending on the dose and user’s tolerance. But THC actually lingers in the body’s fat cells for up to a month.