Gateway Drug Facts

The theory behind so-called "gateway drugs" is that people who use certain substances with moderately harmful effects are more likely to begin using more dangerous, typically illegal drugs.

What are the Gateway Drugs?

• Tobacco, alcohol and marijuana are substances generally considered to be gateway drugs. Although only the latter is illegal under most circumstances, all of these substances have certain restrictions attached to them, such as age thresholds and restrictions on who can sell them, indicating that all three can cause potential harm if used inappropriately.

Where Does the Gateway Lead?

• Ironically, tobacco and alcohol are considered to be gateway drugs to the third drug on that list, marijuana, arguably the most illicit of the three. However, someone who habitually uses all three of these substances is much more likely to use other drugs that act more quickly to alter behavior and have extremely high addictive properties. These drugs include cocaine, LSD and heroin.

Evidence for the Gateway Theory

• According to studies of youth ages 12 to 17 conducted by the National Center on Addiction and Substance Abuse (CASA), marijuana use was found to be 30 times more likely among those who had used tobacco or alcohol in the prior month. The same body of research concluded that those in that age bracket who used all three of these substances were 17 times more likely to have also experimented with at least one harder drug. From a more biological perspective, research done by Dr. George Koob from the Scripps Research Institute indicates that the interaction between cannabis and brain chemicals over time makes the brain more receptive to the use of other drugs.

Criticisms of the Gateway Theory

• Some critics would argue that the gateway drug theory is a false instance of correlation proving causation. These critics say that just because someone uses both marijuana and another, "harder" drug, does not mean that the former drug use caused the latter. They argue that a user may have discovered marijuana first, but it is the same psychological inclination to experiment with illicit substances that led him or her to marijuana, which then leads that same person to a different drug. The fact that, in the CASA studies, boys exhibited much higher correlations than girls might also cast doubts on the gateway theory. If biological factors such as gender so greatly sway behavior, it may be harder to pin causation for the use of one drug squarely and completely on another.

Other Gateway Factors

• Regardless of whether the gateway theory is valid in its entirety, there certainly are some legitimate reasons that the "gateway drugs" are those that are selected first. Because of legality, social acceptability and typical average cost, these substances are much more accessible in most communities than the harder drugs. These reasons alone would explain the chronology, if not the cause, of the pattern of drug use among the nation's youth.