The effects of marijuana include general relaxation, a heightening of the senses, distortion of time sense, and mild euphoria. At high doses, it can cause hallucinations, paranoia, and anxiety. Physical effects include an increase in heart rate, dry mouth, impaired coordination, and delayed reaction time.

Controversy continues as to the drug’s addictiveness. It was once thought that marijuana was not physically addicting because there was no observable withdrawal syndrome. But over the last several decades, improvements in the cultivation of marijuana have led to a marked increase in its potency.

A withdrawal syndrome involving anxiety, insomnia, and tremors has since been described. But an important factor compounding the study of withdrawal symptoms is that marijuana has a very long half-life. As a result it tapers off slowly after use is terminated. Slow tapering is the method of detoxification from other drugs, and it would therefore make sense that a clinically significant withdrawal syndrome is not readily seen.

Marijuana has been shown to interact with the ventral tegmental area of the brain, as have other addictive drugs, and is likely to have the same reinforcing qualities. This interaction probably also accounts for the drug’s mood-altering and euphoric effects. Marijuana is often used in combination with other addictive drugs such as alcohol and cocaine.

Polysubstance dependence is the addiction to two or more substances. It is very common and often includes marijuana dependence. The possibility that marijuana use promotes addiction to other substances has not been well studied but might account for the fact that many addicts start out experimenting with nicotine, alcohol, or marijuana, and then later develop addiction to cocaine or opiates.

The long-term effects of marijuana also remain controversial. A syndrome of poor motivation and apathy (the amotivational syndrome) has been described in chronic marijuana users by some researchers and refuted by others. Marijuana’s ability to produce or to trigger long-term psychiatric problems like schizophrenia has also been described by some and refuted by others.

So what is the truth about marijuana? I think it’s best to look at the studies with a bit of skepticism and instead see what we can observe in people who get into trouble with drugs and alcohol. Although marijuana does not produce the intense craving that drugs like crack cocaine and heroin do, it does alter mood, which allows the user to avoid dealing with reality. And the more one avoids dealing with reality, the more problems one is going to have in life. Even people who use marijuana for medical reasons experience this alteration in mood; it does have a profound effect.

People recovering from dependence on marijuana often have to deal with the regret of missed opportunities, lost productivity, and ruined relationships. Marijuana impairs driving ability and causes accidents. It is a “gateway” drug, especially for young people, opening the door to experimentation with other drugs and exposing the user to the drug culture. Smoking marijuana causes lung damage at a much faster rate than smoking cigarettes does. Proponents of the legalization of marijuana ignore these dangers, or compare them to the dangers of alcohol, which is legal.

A few benign experiences with marijuana give the user a false sense of security because of the lack of immediate consequences. First-time users often feel, then, that everything they have heard about marijuana is a lie, so the warnings about other drugs must be a lie, too.

The bottom line is that marijuana is alive and well in the drug culture, and its use is well represented among people who seek treatment for drug dependence. Controlled medical use may be of benefit to some people, but, contrary to the assertions of those who push for full legalization of marijuana, it is not a benign natural herb. If you put the statistical studies down and just talk to people who are successfully recovering from addiction to marijuana, you will probably find that they take it very seriously.

Elizabeth Connell Henderson, M.D.

Glossary

Appendix A: Regulation of Addictive Substances

Appendix B: Sources of Additional Information