A Brief Overview of the Gateway Hypothesis

December 15, 2021

4 mins

Dane O'Leary


Most experts agree on the general facts surrounding the issue, but when it comes to the gateway hypothesis, there's no consensus on whether there is a causal link between the use of soft drugs and the later use of hard drugs.

The gateway hypothesis attempts to explain why it appears that people who use “soft” drugs seem to have an increased probability of using other, “harder” drugs. The hypothesis proposes that there is something about using less addictive drugs that leads to the use of more addictive drugs. The idea has existed in some form for almost a century. But while there are studies that support the gateway hypothesis, there are conflicting studies as well.

While most experts agree on the general facts surrounding the issue (e.g., if someone uses hard drugs, they probably used soft drugs at some point before that), there is no consensus on whether there is a causal link between the use of soft drugs and the later use of hard drugs.

A Brief History of the Gateway Hypothesis

The gateway hypothesis was initially advanced by Dr. Denise Kandel in 1975 although it didn’t really enter the public consciousness until the ’80s when American leadership really began to wage what we still refer to as the War on Drugs. However, similar ideas were around much earlier.

In fact, the gateway hypothesis has its origins in the 1930s. At that time, the stepping-stone theory held that “consumption of a ‘soft’ drug such as marijuana inexorably sets an individual on a trajectory to addiction to hard drugs.” 

What is a Gateway Drug?

Theoretically, a gateway drug is known by its effects. The effect of using gateway drugs is an increased risk of physical and psychological dependence on drugs in the future. It is a soft drug that increases the probability that a person will later move on to hard drug use. But what is a soft drug?

Soft drugs are drugs that are thought to be less likely to lead to dependence. That’s not to say that they are harmless. There are risks involved with using soft drugs, but the medical consensus is that these drugs are less likely to lead to physical or psychological addiction Hallucinogens like cannabis, mescaline, psilocybin, LSD, ayahuasca, iboga, and DMT are all considered soft drugs. 

Examples of Gateway Drugs

There are many soft drugs that can lead to dependence on other drugs in the future. However, the National Institute on Drug Abuse (NIDA) released the Marijuana Research Report in 2020, which identified marijuana as a gateway drug.

Like marijuana, “alcohol and nicotine also prime the brain for a heightened response to other drugs and are, like marijuana, also typically used before a person progresses to other, more harmful substances,” according to the same report.

Gateway Drugs & the Stages of Addiction

Dr. Nora Volkow, director of NIDA, has conducted research on how people become addicted, breaks the addiction process down into three phases: (1) binge and intoxication, (2) withdrawal and negative effects, and (3) preoccupation and anticipation.

In the first stage, a person takes a drug and their brain releases dopamine, a “feel-good” transmitter. After that, the person experiences withdrawal symptoms in stage two. This can lead them to seek more of the drug. At some point, people who become addicted begin to be preoccupied with the drug and anticipate their next dose in the final stage.

It stands to reason that, as a person’s tolerance for a drug increases and their brain “adjusts by producing fewer neurotransmitters in the reward circuit, or by reducing the number of receptors that can receive signals” they may begin to search for harder drugs in order to achieve the high they experienced before. But there the scientific community has not reached a consensus on the question.

Mixed Evidence for Gateway Hypothesis

While the Marijuana Research Report found that marijuana leads to dependence on other substances, it also found that “the majority of people who use marijuana do not go on to use other, harder substances.” The study’s support for the claim that marijuana is a gateway drug was based on the researchers finding that marijuana users were more likely to develop a dependence on alcohol and nicotine. 

The report notes that it is also possible that “people who are more vulnerable to drug-taking are simply more likely to start with readily available substances such as marijuana, tobacco, or alcohol, and their subsequent social interactions with others who use drugs increase their chances of trying other drugs.” And, even if there is a causal link between soft and hard drug use, there is still research to be done in order to determine exactly what the mechanism is that explains the link.

Do Soft Drugs Lead to Dependence on Harder Drugs?

Though the gateway hypothesis and similar variations of the concept have been around for almost a century, there is still more research to be done in order to determine whether there is a causal link between soft drug use and a later dependence on drugs. But whether the gateway hypothesis is correct or not, addiction is certainly real.

If you or someone you know is harming themselves with drug abuse, contact Never Alone Recovery to learn about the treatment options available for gateway drug abuse and addiction.

gateway drugs, gateway hypothesis

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