Couldn't find what you looking for?


A recent article in Psychology Today posed the question "Is marijuana addictive?" and offered the answer "You can bet your heroin on that." But is marijuana really addictive? And does it really lead to use of heroin?
In a political season in which marijuana initiatives are capturing the attention of voters in the United States and marijuana laws may soon be relaxed, at least in California, the  potential of pot for creating addiction is an important one for about 56 per cent of all Americans--the percentage of US society who admit to having used or continuing to use this most common of all illicit substances. Some of these self-reported pot smokers and brownie eaters admit that they are addicted. Researchers estimate that about 10 per cent of that 56 per cent smoke weed and just can't stop. In the United States, that's about 15 million people.

The percentage of Americans who use marijuana and who are addicted to it, however, is actually smaller than for other common drugs. About 15 per cent of all drinkers in the United States are alcoholics. About 20 per cent of all cocaine users are cocaine addicts. And about 30 per cent of smokers are addicted to nicotine.

Because it's really rare for a marijuana user to experience shakes and vomiting when deprived of their daily toke, most experts question putting marijuana in the category of addictive drugs. The real answer to the question of whether marijuana use leads to addiction, however, depends on how one defines addiction. And understanding marijuana addiction requires understanding the munchies.

The science of the munchies

The way smoking marijuana creates a high involves its content of a chemical called tetrahydrocannabinol, commonly abbreviated THC. This is the chemical that makes the marijuana illegal (or, by its absence, as in the case of hempseed products, legal). THC binds to receptors in the brain that respond to chemicals called cannabinoids. Actually, there are also similar receptors in the digestive tract, which respond to similar chemicals in Cheetos, brownies, cookies, and chips.

There's actually some scientific evidence that if you don't eat the high-carbohydrate foods commonly consumed after smoking pot--and you don't take a drug like heroin--then marijuana won't get you high. That's because the euphoric feeling that comes with smoking marijuana depends on a two-step process.

1. First, the THC in the marijuana has to activate cannabinoid receptors.

2. Then, some other food or chemical, such as the often-mentioned Cheetos or an opioid drug like heroin, also has to activate the mu-opioid receptors.

Foods that are fat, sweet, and salty activate the mu-opioid receptors in much the same way cocaine and heroin do. Cheeseburgers, for example, contain all of the common triggers for this kind of pleasure of response in the brain: bread, cheese, beef including the blood (the cow's blood is particularly high in the chemicals that trigger a pleasure response in the brain), and ketchup, especially when it's made with just a trace of vanilla. These foods contain chemicals that activate the second group of receptors after marijuana activates the first. If you don't want to become addicted to marijuana, just quit feeding your munchies. However, if you don't feed your munchies, you may be more tempted to do cocaine and heroin, assuming they are available to you.

The consequences of using marijuana

Unlike some other ways of getting a high, marijuana cannot be overdosed. As former US Surgeon General Jocelyn Elders put it, "The only way an overdose of marijuana is going to kill you is for a bale to fall on you." Heroin, cocaine, and alcohol, on the other hand, can be deadly if consumed in excess. The social consequences of using marijuana, however, can be life-altering.

In the United States, for example, any student with a record of a drug arrest for marijuana will be denied government funding for education. Not having access to higher education definitely makes a difference in the quality and possibly even the length of life.

Americans of African-American heritage, in particular, are relatively more likely to be arrested for use or distribution of marijuana. With one in four African-American men under the control of the penal system, either in jail or on probation, pot is clearly a life-changing drug for them.

But is marijuana a gateway drug?

Another valid concern about marijuana use is whether it is a gateway drug, whether it leads to the use of "hard" drugs like heroin and cocaine. This is a concern of thoughtful voters who are deciding initiatives to decriminalize pot.

Biologically, the answer is clearly in the affirmative. Yes, in the absence of food that is also used addictively, it is only natural for users of marijuana to use cocaine and heroin. Drugs that activate the opioid receptors complete the process that creates the feeling of a high from using pot. Whether people who indulge in weed actually use the hard drugs, however, involves multiple variables. People are not necessarily limited by their biology. When it comes to drugs, they are more likely to be limited by their social environments. "Bad" environments or unstable environments invite drug use.

1. People who are exposed to cocaine or heroin before birth (in the womb) are more likely to seek cocaine or heroin if they become regular marijuana users.

2. In some studies, teens were more likely to "graduate" to using Ecstasy if they took the club drug ketamine than if they smoked marijuana, probably because Ecstasy is also a club drug.

3. A study of 6,466 by psychologists at Kent State University in Ohio in the United States found that teens who use inhalants usually used marijuana first, although these findings are hard to reconcile with other studies that have found that legal aerosol inhalants are the most commonly used drug among all American teens, and that inhalants are used much more frequently than marijuana.

4. A study of 9,282 teens in Australia found that teens who developed cocaine or heroin addiction usually used cocaine or heroin before trying marijuana.

5. A study of Hispanic teenagers in the USA found that teens aged 14 to 17 whose families moved from city to city were more likely to try hard drugs after using marijuana, but most teens who lived in the same city for their entire high school years did not try hard drugs.

In other words, it is not easy to see a clear, real-world pattern between marijuana use and later use of other, more dangerous drugs. Teens who go to places where various kinds of drugs are available tend to try them all, but teens who start with one drug usually do not venture out just to try more. The teens and adults who use hard drugs typically spend their early childhood in environments where hard drugs are used. Individuals who were exposed to hard drugs in utero, before birth, tend to use them in adulthood, but that could be due to availability more than biology.

The real reason marijuana usually is not a gateway drug, however, may come back to the way it works in the brain. Users who follow the typical pattern of smoking and eating reinforce the relaxing euphoria of the drug, and have no motivation to seek out other illicit pleasures.

The forthcoming DSM-V (Diagnostic and Statistical Manual V), the "Bible" of the mental health field, will be classifying dependence on food as an addiction, and it is likely that marijuana will be defined as a gateway drug to carbohydrate addiction. As long as it is only a gateway to carb addiction, however, its effects on physical health are much easier to manage.

  • Ghozland, Matthes, Simonin, Filliol, L. Kieffer, and Maldonado (2002). Motivational Effects of Cannabinoids Are Mediated by μ-Opioid and κ-Opioid Receptors. Journal of Neuroscience, 22, 1146-1154.
  • Photo courtesy of Brett Levin by Flickr :