The First Stone Age

About a hundred thousand years ago (we're guessing here), a half-frozen cave man named Urg (we're guessing here, too) made a discovery so big that its effects are still being felt all over the world.

Urg was freezing, so he tossed a bundle of plants he'd tugged out of the ground that afternoon onto the fire in his cave. And as he and his friends squatted over the fire and warmed themselves (and wished they had a GameBoy or something to make life less boring), they noticed strange changes creep over them.

The shadows on the cave walls got weird, for one thing, and the fire seemed way cool.

They also noticed that the chief's jokes (which they had all heard a thousand times) were funny again — at least everybody laughed and pounded each other on the back and rolled in the dirt.

If Urg and his friends had given it any thought (instead of trying to rig a sound system out of some rocks and old mastodon bones they found in a corner of the cave), they would have noticed other changes come over them, too — changes in the way they thought and felt and acted, that we're only now beginning to fully understand.

Because (surprise!) the weed that Urg threw on the fire was marijuana and, without knowing it, Urg and his pals had thrown the world's first pot party.

This story isn't true, as far as anybody knows. (After all, prehistory wouldn't be pre-history if anyone left notes.)

On the other hand, it makes as much sense as a lot of other stories that have been passed around about marijuana since the first Urg noticed it growing down by the local watering hole and wondered what it was good for.

That's the point of this pamphlet. Because even though Urg didn't find all the answers to that question, the people who came later sure kept asking.

Rope or Dope?

Did they ever. In fact, at various times and in various places, they found uses for it for about every purpose you can imagine, and a few more besides.

The plant itself (sometimes called hemp and known botanically as cannabis sativa) is an excellent source of fiber, and has been used throughout the world to make rope and cloth and paper.

In fact, access to hemp and the ability to make rope from its fiber was so important to early tribes that it could spell the difference between first place and dead last in the battle for survival.

But man does not live by fiber alone, and hemp came to mean more to early humans than mere raw material for rope and clothes. To the ancient Chinese and others, it was a medicine, and they used it to treat a variety of ailments, from backaches and bad disposition to sunstroke and dysentery.

In India and Japan and Persia, it was revered as a holy plant and was used as a sacrament in religious ceremonies. In fact, 10th-Century A.D. Hindus were so impressed by the effects it produced that they called it indracanna, or the "food of the gods."

"Food of the gods" or not, the plant (and the drug contained in its flowering tops) has made the rounds under a lot of different names over the years: It's been called bhang and ganja in India and Jamaica, boo, gage, pot, weed, reefer, grass, muggles, mezz, moota (moota?) and a thousand other names in a thousand other places.

But whatever you call it, the real story about marijuana today involves the drug inside the plant.

And no matter what form that drug comes in — whether plain, old-fashioned, crushed-and-dried pot or the pressed resin known as hashish or the liquid resin known as hash oil — that story's a big story today, indeed.

Inside Story

So what kind of drug is marijuana, anyway?

That's a simple enough question. Too bad it doesn't get a simple answer.

Why? Because marijuana isn't a simple drug. It isn't even a single molecule like other drugs, including alcohol and cocaine.

Instead, it's a complex mix of 421 different chemicals - -61 of which, known as cannabinoids, are found nowhere else in nature.

The most important cannabinoid in pot is a little number known as delta-9 tetrahydrocannabinol (THC, for short). THC is the main mind-altering ingredient in marijuana, and the biggest news about it is how much of it is turning up in new, high-potency forms of pot.

Just a few years ago, most marijuana sold in the United States averaged about 2 percent of the drug, which was (and is) plenty.

Today, it's not hard to find pot with a THC content of 7, 8 or even 10 percent. And that extra potency packs a punch — in the form of more intense effects and greater potential risks.

Still, THC isn't the whole story. Because even though it's the chemical most responsible for pot's effects, it's not alone. Other cannabinoids — with names like cannabinol, cannabicyclol, and cannabidiol — are there, too. And, for the moment, they're still mostly unaccounted for.

Personal Effects

Since everyone has some idea about what the marijuana high is like, we're not going to waste a lot of time talking about that.

What we will say is that most effects — euphoria, sensory distortions, and altered feelings — kick in fast, usually before a smoker finishes a joint.

Other effects kick in quickly, too, including time distortion and increased appetite (AKA "the munchies"), which can show up in the form of an inexplicable urge for a 36-inch extended-family-size pizza or a sudden impulse to build a truly world-class sub out of everything in the refrigerator.

Most subjective effects peak in about an hour and wear off in 2-4 hours. So do pot's main objective effects — ones that are detectable outside the body, like bloodshot eyes and increased heart rate.

We could spend a lot of time talking about external changes. But if we did, we'd miss the real story, the one that takes place inside the body — and mind.

Tissue Issues

To see how that story unfolds, let's take an imaginary trip inside the body tissues and organs of a smoker to track some of the more important changes as they occur.

Our trip won't cover all the things that pot does in the body, but it should be enough to give you a better idea of what marijuana does to a person when a person does marijuana.

Ground Zero

When a smoker lights up, the first big biological change comes in the form of a blast of tar and other gases that rushes to the lungs, after first ir-ritating the tissues of the mouth, nose, and throat.

You might also hear a cough as the lungs do what they're supposed to do — expel irritants.

Gradually, though, the lungs adjust, and the smoke stays down. That's when THC and other chemical components of marijuana pass through the bronchial tubes to the capillaries, where they're absorbed into the bloodstream.

Once in the bloodstream, cannabinoids rush to the heart, where they trigger a jump in heartbeat, sometimes as much as 50 percent above resting rate.

That increase isn't a problem for most people, but researchers warn that it could be more serious for older people and those with heart disease.

BioTransport

All that activity in the heart has one clear effect, though: It pumps cannabinoids to other body organs, triggering a variety of physical effects, from decreased pressure inside the eye to increased muscular relaxation — also not a problem for most people.

But since cannabinoids are fat-soluble, they zero in on areas having a high fat content, such as the sex glands and brain.

Once THC hits the brain and acts on receptors there, the subjective feeling of being high kicks in. That's when marijuana's thought and mood changes start.

At this point, the liver and kidneys swing into action, breaking THC and other cannabinoids down into less-complicated, more easily-eliminated chemicals.

About half the breakdown products (or metabolites) leave the body within 24 hours, but others — stored in fatty tissue — hang around, almost like biochemical leftovers.

But unlike leftover food in a refrigerator (which can disappear faster than a pot smoker can say "Hold the mayo"), cannabinoids are detectable for days or weeks.

What effects do they produce while they're hanging around?

No one knows for sure, but since they are still drug molecules, they could cause subtle effects that would be almost impossible to trace.

Pot's Hot Spots

So much for the grand tour. Now we'll narrow our focus down to examine what pot does to key body systems.

Because even though no one knows yet what all those effects are, we know enough about some of the hotter research topics to consider them in detail.

These effects are grouped around three major body hot spots: the lungs, brain, and the organs and glands that regulate growth and sexual development.

Lungs

Probably the clearest health risk posed by pot is the danger to the lungs.

That's because marijuana smoke contains the same cancer-causing chemicals found in tobacco smoke. And since pot smokers hold marijuana smoke in the lungs longer, regular use could pose the same kinds of cancer risks as cigarette smoking.

In addition, pot smokers also raise their risk of other lung problems, including bronchitis and emphysema.

That risk is considered higher still for people who smoke both pot and cigarettes.

Brain

Since THC accumulates in the brain for such long periods of time, and since the brain is so near and dear to all of us, research into its actions there has been the most closely-watched area of marijuana research in recent years. And from what we know today, those effects are something to think about.

he most striking set of effects involve memory. Recent studies show that pot can disrupt short-term memory — the process in which recent events are encoded and stored in the brain.

This effect can be a disaster if you care about your grades and your future — and a serious drag, even if you don't.

Other potential problems aren't much fun, either.

Calculation skills, reading comprehension, and other abilities can also be dulled by the drug, with effects lasting several hours after the high disappears. And the more you smoke, the longer they seem to last.

The same thing happens to reaction time and visual tracking ability, which could be a problem in certain circumstances, like driving a car. That's why it's as bad an idea to drive after smoking as it is to drink and drive.

Growth & Sexual Development

Another hot spot that's attracting serious scrutiny involves body systems that regulate growth and sexual development.

Interest here has heated up as the age of pot smokers has dropped. And as users' ages have fallen, concern about possible risks have increased — and for good reason.

What's known at the moment is that marijuana causes changes in hormone levels of users which could alter normal patterns of growth and sexual development.

In boys and men, it causes decreased blood levels of testosterone, the main male sex hormone. In women and girls, levels of two hormones drop following marijuana use.

Researchers aren't sure if any serious problems result from reduced hormone levels in adults. What it could mean to younger people is another question, altogether.

And according to most experts, it's as good a reason as any for kids to pass on pot altogether.

Up In Smoke

Urg and his pals (remember them?) didn't have the gadgets to measure all the effects of pot. But even if they did, they would have found that some effects are hard to measure — so hard, in fact, that their modern-day descendants are still arguing about them.

One thing a lot of people are still arguing about is marijuana's links to motivation, and whether or not it reduces the drive to excel. In the past, this suspected effect was labeled "amotivational syndrome."

Today, most experts consider marijuana use and decreased interest in goals as a kind of chicken-and-egg situation. (Does pot reduce motivation or does it just appeal to people who are already unmotivated?)

On the other hand, many ex-users call pot a "spectator drug," one that turned them into passive onlookers in their own lives.

One possible reason for the passivity linked to pot is that smokers don't have to actually do anything to be happy or entertained. All they have to do is get high, and pot does the rest.

And while it might look like fun to cruise through life stoned, it's a lot less fun than learning to pull your own strings and make life happen the way you want it to happen. Think about it.

Because too many people already have had to admit they watched the best years of their lives go up in smoke. They just didn't realize it at the time.

Rap Up

Okay. That's the story (more or less) of marijuana in America today. Some love it, some hate it, and there's even one or two out there (we're guessing again) who just plain don't care. So what's left to say?

Probably the biggest thing to remember is that marijuana is a complicated drug, so much so that, even after decades of research, we still can't describe all of what it does, everywhere in the body.

Something else to consider is that long-term effects still aren't fully understood. But just because researchers can't prove the problems they suspect doesn't mean they're not there.

After all, it took 100 years for the case against cigarettes to be nailed down, but the risks were real all along.

That may be the most important point of all to keep in mind about marijuana today — to have a healthy respect for it and the problems it can cause, and steer clear of them.

Because even though a lot of the wild and woolly "reefer madness" scare stories of the past weren't true, that doesn't mean pot can't cause real problems for real people. Make sure you're not one of them.

Sidebar: Marijuana & the Mind

As important as pot's effects on the body are, its effects on personality and behavior are just as important and every bit as complex.

Interest in marijuana's effects on the mind have heated up in recent years, since the discovery of receptor sites in the brain for THC, pot's main mind-altering ingredient.

Main concerns at the moment revolve around the following issues:

Personality changes. "Reefer madness" stories of the past were far-fetched, often the ravings of the misinformed or the misguided. But recent research suggests that marijuana may leave a more lasting mark on the mind.

In a 1990 study, researchers at the Karolinska Institute in Stockholm found that people who smoked pot more than 10 times were 2.3 times more likely to develop schizophrenia than non-smokers. And even though it remains unclear whether the link is causal or coincidental, those who smoked 50 times or more were found to be 2.9 times more likely than non-smokers to develop the disease.

Panic reactions. High-potency pot is linked to an increasing number of panic reactions. In 1999, panic and anxiety reactions contributed to more than 87,000 U.S. emergency-room admissions.

Memory deficits. Pot's effects on short-term memory have been known for a long time. What's new is evidence that impairment may last as long as six weeks after use is stopped by heavy smokers and