Gateway Drugs: What are They?

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Gateway Drugs and Addiction

The gateway theory of substance abuse theorizes that an individual who uses one illegal or dangerous substance will be more likely to abuse other substances. The idea was first studied in the 1970s and was extremely popular through the 1980s. The term itself was coined as part of the terminology of the War on Drugs.

The theory of the gateway hypothesis categorizes specific drugs as being an entry point to addiction. An adolescent’s early experimentation with gateway substances such as alcohol, cigarettes, or marijuana is believed to cause an escalation to more addictive drugs in adulthood. The most commonly used illegal substances are heroin and opioids, cocaine, and amphetamines. These are all illegal in the United States, though, ironically, with some states legalizing cannabis, the original basis for this theory has been undercut. Early-onset drug experimentation is a well-known characteristic in the literature on substance abuse and dependence.

How Does the Gateway Hypothesis Work?

According to the hypothesis, a gateway drug alters the neural pathways of the brain, and an interaction between both genes and the environment is involved. Research indicates that animal studies of addiction show that when animals begin to use addictive substances at an early age there is a greater probability that they will develop addictions to other drugs.

Post-mortem analysis indicates that the reward centers of their brains were altered compared to normal animals. This led to the conclusion that early exposure to some drugs leads animals to develop abuse issues with other drugs. This seems to correlate with what has been observed with young people whose long-term drug use seems to be predicted by early usage.

The gateway hypothesis also suggests a significant genetic component when it comes to drug abuse. There are also environmental factors and personal components. These factors may contribute to alterations of neuropathways in individuals that are part of the gateway hypothesis. Researchers looking at drug abuse have observed these factors when it comes to poly-substance abuse.

In contrast to the gateway hypothesis is the common liability model, which seeks to explain the relationships between different mental health disorders that may coexist. This model views individuals with one type of mental health disorder as being more likely to have additional mental health disorders, including addiction.

Gateway Drugs

While any drug that is abused can be considered a potential gateway drug, only a few are generally considered to be potential gateway drugs, according to the gateway hypothesis.


Tobacco is a leading cause of death and disability in America. It shares many close associations when it comes to dependence on other drugs. Research has shown that individuals who begin to use tobacco products early in life are more likely to develop issues with substance use and abuse with substances like alcohol, marijuana, cocaine, and heroin.

A variety of factors explain why nicotine is considered a potential gateway drug. These include:

• Learning theory: The idea is that when a person feels their use of nicotine is acceptable it can make it easier for them to use other drugs.
• Pharmacological issues: Biological changes that occur because of nicotine use are similar to those caused by other drugs.
• Social factors: Many start to use tobacco because of peer pressure.

Various studies show a correlation, including a study from 2011 that found that nicotine-laced water given to rodents early in their development later caused an enhanced response to cocaine. A 2014 study hypothesized that nicotine fits each facet of the gateway drug theory but not the common liability model.

Data from the CDC (Centers for Disease Control and Prevention) indicates an association between using tobacco and illicit drugs. Highlights of the data include the following.

• Over 15% of smokers reported using marijuana over a month-long period versus just 3% of non-smokers.
• For cocaine use during a duration of a month, 1.8% of smokers used the drug versus just 0.2% of non-smokers.
• People self-reported non-medicinal use of prescription drugs to the tune of 5.3% for smokers versus 1.2% for non-smokers.
• Heroin use was nonexistent for non-smokers but 0.3% for smokers.
• Just under 43% of smokers reported binge drinking over the past month versus 17.5% for non-smokers.
• Tobacco users were also more likely to admit to heavy drinking over the past month.


Alcohol is also considered a gateway drug. According to SAMHSA, in 2015, 20.8 million people age 12 or above had an issue with substance use disorder, with 15.7 million having alcohol issues.

According to The National Institutes of Health, people between 18 to 24 are more likely to have an alcohol use disorder coupled with other drug disorders. A comprehensive study of 50,000 students distributed between the eighth, 10th, and 12th grades found that:

• Of the 12th graders who reported using alcohol in addition to marijuana and tobacco, 54% said they used alcohol first while 32% used tobacco first and 14% had tried pot first.
• Students who reported alcohol use when in the eighth grade were more likely to have greater rates of illegal substance use throughout their lives than those who reported they first used it after they started high school.
• Eighth-graders who used alcohol were also significantly more likely to use other illicit substances.


Pot is considered by many to be the major offender when it comes to gateway drugs. There is consensus that many adults who become addicted to opioids, meth, and other addictive substances tried pot first. Many animal studies indicate that young rodents exposed early to THC are more likely to experience addictions to other substances. This early exposure can also cause changes to the rodents’ neuropathways that make them more susceptible to addiction.

According to a large longitudinal study that spanned a 25-year timeframe, there was a strong association between early cannabis use and adult addictions. A 2015 national epidemiological survey focused on alcohol that looked at over 6,600 people found that those who regularly used cannabis were using it prior to other drugs, and there was a 44.7% chance of the pot users also using other drugs.

Is the Gateway Theory Valid?

Despite a large body of evidence that many consider definitive, not all researchers are convinced that both animals and human beings who use drugs like alcohol, tobacco, or marijuana will go on to abuse other drugs later. Many of the issues associated with the gateway theory relate to, among other factors, several methodological limitations in terms of the supporting research.

Problems With Animal Behavioral Models

It’s not a given that animal models of behavior will equate to human behavioral responses. Animals that self-administer drugs while captive in cages are not representative of either normal animal behavior or a decent representation of human behavior. It was discovered, for example, that animals who were provided enriched environments to dwell in versus standard barren facilities with no comforts experienced different outcomes. They were far less likely to self-administer drugs. While animal models can offer insights, there are limitations. It’s particularly important to recognize that human behaviors are far more complicated.

Correlation Does Not Equal Causation

Studies that look at correlations and associations are not properly used as evidence of causal connections. Each study used to demonstrate the relationship between early human examples of substance use phenomenon and later drug-seeking behavior was part of what is defined as correlational studies. Associations are examined, but cause and effect are not carefully evaluated. Researchers can and do properly hypothesize between relevant variables in these studies; however, the implication that this proves the link between early marijuana use followed by a causal relationship to later cocaine or other drug usage is not proved.

Relationships Between Disorders That Co-occur Are Complex

The relationships that seem to occur between both comorbid, or co-occurring, disorders are not simple and easily understood. Potential use of forbidden substances could be due to factors ranging from trauma and peer pressure to a tendency towards antisocial behavior. Peer pressure is particularly powerful — simply being in a social milieu where individuals abuse illicit drugs increases the probability of group dynamics supporting drug use.

Human Factors

Neuroimaging studies of people along with animal studies do suggest an alteration of the neurological pathways for those dealing with substance use disorder, but choice plays a key role. One issue commonly seen with medical models of behavior is the tendency to assume that individuals with a history of chronic substance use disorder have lost the ability to choose sobriety or continued drug use. However, the success of treatment programs belies this. Cognitive-behavioral therapy is one example of a modality that can help the brain to make better choices.

Common Liability May Be a Better Model

Instead of the gateway theory, which attempts to designate a particular gateway drug that leads to further issues with substance abuse, there is sufficient evidence that early exposure to drugs can lead to long-term challenges regardless of the specific type of drug. There is research showing a correlation between abusing prescription medications early in life and higher rates of alcohol or marijuana use later. Since not everything is a gateway drug, the common liability model might be a better fit.

It is clear that there is evidence connecting early use of various potentially addictive substances to increases in the risk of an individual abusing other drugs. The reason for this, however, is not completely clear. Factors such as genetics and environment should be considered.

Early alcohol use is the gateway drug most likely to cause later addiction; however, even in this case, the common liability model might be more relevant.

At Granite Recovery Centers, evidence-based practices are emphasized. A hands-on approach is coupled with the best of treatment modalities. Each client experiences a personalized approach.

Two components are regularly used. One is the REST program. This is the Recovery Education and Skills Training Program, which provides comprehensive lectures, discussions, and an action-based curriculum integrating proven 12-step principles. The other component is to use evidence-based models and practices. Both of these methodologies are powerful tools for achieving the best long-term outcomes for clients.

For over 10 years, Granite Recovery Centers has been helping to transform the lives of those who have endured the pain of addiction. In our New Hampshire facilities, a full continuum of care is provided. Everything from medical detox to medication-assisted treatment, residential and extended care programs, sober living, and intensive outpatient services ensure that clients have the tools they need to regain control. Our growing community of those who have reached their goals provides peer support. The compassionate and knowledgeable staff and medical team look forward to helping you attain a hopeful future. Contact us today for more information.

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