Close up of addict buying dose from drug dealerThe gateway drug theory has been around ever since the 1970s government-led War on Drugs. Scientific research published on the National Institute on Drug Abuse website shows there’s some hard evidence to back up the idea that people who abuse legal or illegal drugs as adolescents and young adults are more likely to develop serious addiction problems later on in life.

That said, plenty of individuals who weren’t exposed to substances as teenagers go on to develop substance use disorders. Likewise, the majority of people who experiment with cigarettes, marijuana, alcohol or even harder drugs in their youth don’t spend their entire lives battling addiction. Read on to find out more about the gateway hypothesis and how the onset of addiction is far more complex than we’ve previously understood.

The Gateway Drug Theory

Man sitting at bar counter with a glass of whiskey and cigarAccording to gateway drug theory, cigarette, alcohol and cannabis use in young people leads directly to the use of more dangerous drugs later in life. Although they might be legal, the way these substances interact with the brain is similar to substances like methamphetamine, opioids and cocaine.

Every time you use cannabinoids, smoke a cigarette or drink an alcoholic beverage, your brain is flooded with various levels of a neurotransmitter called dopamine. This chemical is usually reserved by the brain for use when you do something pro-social and survival-based, like eating, reproducing or performing well at work or school.

However, psychoactive drugs (including tobacco and alcohol) hijack this system, which is why cravings occur and feel so compelling — your brain actually urges you to take dangerous drugs!

Why Are Young People More Vulnerable?

Getting caught up in this synthetic reward cycle is much easier for young people, whose brain isn’t fully developed. Areas that are responsible for self-control and decision-making are last to fully form, and using mind-altering chemicals during this critical stage can cause a young substance abuser’s brain to develop differently than someone who never uses anything psychoactive.

Dopamine and Substance Use in Rodents

The main evidence we have for gateway drug theory is that marijuana use in young rodents led to a diminished pleasure response in adulthood. It’s crucial to note that the large area at the front of the brain that’s responsible for conscious activity is much larger in people than in mice. As such, where a rodent might be powerless against its brain chemistry in adulthood, a person is potentially able to exercise more control over their actions.

That said, even anecdotally, people who seek addiction treatment are more likely to have tried drugs or alcohol for the first time when they were young. There is plenty of evidence that supports the gateway effect, but why it happens is still not fully understood. What we do know is that mental health, genetics, family history, peer pressure and other environmental factors also play a role in the onset of any SUD.

Habit-Forming Gateway Drugs

The main drugs people consider to be gateways into cocaine use, alcohol use disorders, heroin addiction and worse in adult life are tobacco, alcohol, cannabis and prescription painkillers.


The strongest correlation between addiction and early substance use is for cigarettes. Not only does smoking cause more deaths than any other lifestyle factor but it’s also seen as the gateway for addiction. Whether it’s the fact that being addicted to nicotine affects the dopamine receptors or it primes the brain for addiction in some other way, smoking in teenagers is a sign that addiction might occur later in life.

Even with strong correlation, there’s no evidence that suggests every kid who smokes will go on to become a cocaine user. Scientists hypothesize that it’s likely a combination of factors that lead to addiction in later life, with cigarette smoking in youth serving as one risk factor. Nonetheless, if your child has picked up the habit of smoking, we’d strongly recommend you talk to them on a deep level about any issues they might have in their life. Addictive behaviors are often coping mechanisms or attempts to make the person feel better.


According to the CDC, more than half of 12th-graders have tried alcohol. Binge drinking is particularly common among teenagers, and getting into the habit of getting extremely intoxicated can have lasting effects on the brain, as well as behavior. Drinking is legal, and this leads many teenagers to believe it’s not as harmful as other substances. In fact, along with smoking, alcohol abuse is a leading cause of death and disease in the United States.

Plenty of people are able to have a drink every now and again, but if a young person is continually getting blackout drunk, there’s a strong chance there are some mental health issues that need addressing. Still, lots of young people go through a phase of heavy drinking and grow out of it entirely within a short space of time. It’s down to the individual and their loved ones to identify if substance abuse is a sign of something more serious as soon as possible.


Before widespread legalization, cannabis was seen as the main gateway drug because it introduced young people to drug dealers who might try to sell them something else. While this is no longer a risk in many states, the same potential problems are present as with alcohol and cigarettes.

Wanting to be inebriated on a regular basis is a sign there’s some kind of imbalance in a person’s life. Cannabis might make some people feel they want to try a stronger type of sedation or psychoactive effect. However, it’s unlikely that someone with no mental illness, history of trauma or genetic predisposition would jump from cannabis use to more dangerous drugs.

Prescription Drugs

Two out of 10 12th-graders are reported to have used prescription medication for something other than it was intended. Athletes are at an increased risk when it comes to these types of substances, with injury and the risk of losing your place on a team driving up the use of prescription painkillers in these groups. Still, exposure alone wouldn’t usually be enough — the person would have additional factors driving them to move from prescription drugs to harder substances.

Correlation Isn’t Causation

Early exposure to alcohol or drug use, including tobacco, is just one of a myriad of risk factors for the development of substance use disorders in later life. While young people using illicit substances definitely correlates with drug addiction in adulthood, there’s no proof for direct causation. It’s important to note that someone who uses addictive drugs as a teenager isn’t powerless to defend themselves against a future filled with illicit drug use.

Get Help for Substance Abuse Today

There are a number of genetic and environmental factors, in addition to potential mental health issues, that also contribute to the onset of an SUD. If you’re worried about the effects of drug or alcohol use on you or a loved one, call our Fort Myers rehab today at 844-254-9664.