Updated on April 3, 2024
9 min read

What Are Gateway Drugs?

For many people, addiction is a road that begins with seemingly harmless choices. What starts as a puff of a cigarette or sip of someone else’s drink can quickly become substance use.

This substance can serve as a gateway drug, leading down a path of addiction and dangerous outcomes.

What are Gateway Drugs?

A gateway drug refers to a substance that is believed to increase the likelihood of progressing to the use of more potent and harmful drugs. They can be a precursor to other drugs or an entry point into a broader cycle of drug abuse.

Gateway drugs flood the brain with dopamine. This changes neural pathways, making people more susceptible to drug addiction. The most common gateway drugs are:

  • Nicotine
  • Alcohol
  • Marijuana

For decades, the gateway theory influenced assumptions around drug abuse. However, some experts have criticized this approach in recent years, arguing it’s incomplete.

History of Gateway Drugs

The idea of a progression in substance use from weaker to harder drugs goes back to the 1930s. Known as Stepping Stone Theory, it suggested an inevitable progression from marijuana to the use of harder drugs, such as heroin. 

However, in 1975, Denise Kandel’s Gateway Hypothesis challenged this idea. Unlike the Stepping Stone Theory, the Gateway Hypothesis suggests that gateway drugs don’t always lead to more severe drug use.


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The Gateway Drug Hypothesis 

While known under various names since the 1930s, Denise Kandel coined Gateway Hypothesis in 1975. Kandel noted in two studies that those who used dangerous substances such as opioids or amphetamines progressed through stages. 

According to Kandel’s research, 27% of young people who smoke marijuana first experimented with alcohol and tobacco products. Additionally, 26% of young adults who used marijuana later progressed to LSD, amphetamines, and heroin. 

In other words, gateway drugs are a starting point for most people who turn to harder drugs.

Prescription Drugs and Gateway Drug Theory

Prescription drugs, such as painkillers and other medications, have also been linked to the gateway drug theory. Studies suggest that these substances can lead to the use of illicit drugs.

Prescription painkillers are particularly dangerous, as they can lead to addiction and increased risk of overdose. This is particularly true when these drugs are obtained illegally.

Prescription pills, such as sedatives and stimulants, can also lead to addiction if taken in large doses or without a prescription. People may also become addicted to these drugs after trying them recreationally.

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How Accurate is the Theory? 

Controversy surrounds the legitimacy of the Gateway Theory, which fails to account for the causes of addiction sufficiently. 

Critics argue that environmental factors, genetics, and mental health play a significant role. It’s important to note that not everyone who uses gateway drugs progresses to using more dangerous substances.

Common Gateway Drugs 


Nicotine is one of the most common gateway drugs, followed by alcohol. It’s a stimulant that gives tobacco users a sense of mental alertness. 

Nicotine is most commonly inhaled through cigarette smoke or vaping devices, though it can also be absorbed into the gums via snuff. It’s also one of the most common substances young people try for the first time use.

Nicotine is habit-forming and is considered by some to be as addictive as heroin. This is partly due to its high accessibility and ability to amplify pleasurable activities.

Nicotine Side Effects and Withdrawal Symptoms

Short-term side effects of nicotine use include:

  • Increased adrenaline and mental alertness
  • Reduction of anxiety
  • Increased heart rate

Symptoms of nicotine withdrawal include:

  • Mental sluggishness
  • Increased anxiety
  • A sharp increase in appetite
  • Cravings for more nicotine
  • Headaches
  • Fatigue
  • Constipation

Prevalence of Nicotine Addiction

There’s a strong link between illicit drug use and tobacco products, especially by young people. According to a 2014 study, 87.9% of young adult cocaine users had smoked cigarettes.7 

By contrast, only 2.9% of cocaine users had no cigarette experience. Studies in mice also show that nicotine primed them to self-administer cocaine, but the reverse was untrue. This indicates nicotine is uniquely suited to be a gateway drug.7 

Another rodent study demonstrates nicotine’s biomechanical mechanisms in “priming” the brain for other illegal drugs like cocaine. The results showed that biological changes occurred in the brain’s reward-seeking pathways.12 

Overall, multiple studies suggest that these effects are most substantial during adolescence. This indicates that young people exposed to nicotine are particularly vulnerable to future substance use disorders (SUD).3 

Illicit Substances Linked to Nicotine Use

Illegal substances linked to nicotine use include:

  • Marijuana: According to a Johns Hopkins study, young people who smoke cigarettes are seven times more likely to try marijuana. 
  • Cocaine: Studies of mice pre-treated with nicotine show a heightened response to cocaine compared to control groups.
  • Heroin: Evidence suggests nicotine primes the same receptors in the brain that respond to opioids.


Marijuana is the most commonly used drug after nicotine and alcohol and the most frequently used illegal drug overall. It’s typically smoked, though users can also ingest it. 

Marijuana acts upon the brain through the chemical THC, a psychoactive compound that produces euphoria and heightened sensory perception. 

Marijuana Side Effects and Withdrawal Symptoms

The most common side effects of marijuana are:

  • Increased appetite 
  • Altered sense of time
  • Distrust
  • Paranoia 
  • Poor memory
  • Decreased reaction time
  • Anxiety
  • Euphoria 

Their long-term effects associated with chronic marijuana use include:

  • A permanent drop in IQ by as much as eight points
  • Various mental health disorders, such as schizophrenia and depression
  • Lower self-esteem
  • Poor academic performance
  • Financial difficulties
  • Increased risk for mental health problems

Epidemiological studies have yielded conflicting results on marijuana’s role as a gateway drug. Several variables appear to play a role, including the drug’s potency, availability, the user’s mental health and age, and potency level.11  

However, animal studies have shown a significant overlap in the neural pathways affected by THC and opioids. Adolescent rodents introduced to cannabis exhibited a greater preference for opioids than the control group.3 

Illicit Substances Linked to Marijuana Use

Illegal substances linked to marijuana use include:

  • Alcohol: Per the National Institute on Drug Abuse, marijuana users are likelier than non-users to develop alcohol use disorder (AUD). 
  • Heroin: According to the CDC, people addicted to marijuana are three times more likely to be addicted to heroin.
  • Cocaine/Crack: Studies indicate that most crack-cocaine addicts are also prior marijuana users.


Like nicotine and cannabis, alcohol is a popular gateway drug. It’s a central nervous system depressant and the active ingredient in beer, wine, and spirits. It’s consumed primarily for recreation but also for cultural and religious reasons.

When consumed, the user feels a sense of euphoria, relaxation, and increased sociability. Alcohol is habit-forming, and excessive consumption induces physical dependency

Alcohol Side Effects and Prevalence

Some other alcohol side effects include:

  • A decline in fine motor skills
  • Increased aggression
  • Memory lapses
  • Slurred speech

The long-term adverse health effects of alcohol use disorder are numerous. According to the Centers for Disease Control and Prevention, these include:

  • High blood pressure
  • Increased risk of heart disease and stroke
  • Liver disease
  • Cancer

According to the National Institute of Health, almost 6% of adults in 2018 experienced AUD. Thus, nearly every person has the experience, either personal or through loved ones, with AUD.9 

Illicit Substances Linked to Alcohol Use

Illicit substances linked to alcohol use include:

  • Cocaine: Per one study, alcohol, along with depression, is second only to cannabis as a predictor of future cocaine addiction.
  • Marijuana: A study on 12th graders found that those who consistently used alcohol are sixteen times more likely to use marijuana.
  • Nicotine: A study with 12th graders as participants suggests that those who drink alcohol regularly are much more likely to also use both legal and illegal drugs.14

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How Gateway Drug Use Can Lead to Addiction

Studies are shedding light on the biological mechanism that drives addiction. It’s been noted for a long time that there’s a pattern in how people progress from experimenting with gateway drugs to more harmful substances. 

Researchers have examined animal behavior and found that all drugs — including gateway drugs — activate the same neural pathway and cause structural and chemical changes in the brain. This makes individuals more susceptible to developing SUD.

The Role of Early Exposure in Gateway Drug Use

Early exposure to gateway drugs is a strong predictor of later SUD. Two factors that can increase the risk of early exposure are:

  • The age at which a person first tries the drug: A person who tries a gateway drug at a young age is more likely to progress to other substances.
  • The availability of the drug: Easy access to gateway drugs increases the likelihood of progression to more dangerous substances.

People with multiple risk factors are more susceptible to progressing from gateway drug use to addiction. This is especially common among those who experiment at an early age.

Risk Factors for Illicit Drug Use

Risk factors include:

  • Family history of SUD
  • Low academic achievement
  • Poor mental health
  • Negative peer groups
  • Sexual abuse
  • Lack of parental guidance

Mental Health and Substance Use Disorders

Mental health disorders and substance use disorders are closely linked. Mental health issues, such as depression and anxiety, can increase the risk of substance abuse.

Those with mental health problems may use drugs to cope with their symptoms. Meanwhile, substance use can develop mental health disorders due to changes in brain chemistry and structure, leading to an increased risk of depression and anxiety.

The relationship also works the other way around. Drug or alcohol use can lead to depression and anxiety. Likewise, substance use disorder can lead to physical and psychological dependence.

How to Prevent Addiction Before It Starts

Research indicates that the adolescent brain is especially receptive to SUD development.11 Therefore, educating young people about the perils of drugs is critical to curbing addiction. 

Therefore, it’s essential to inform parents, teachers, and other adults in the lives of young people about the specific dangers of this stage of life for drug misuse. Raising awareness and taking proactive measures can protect our youth and prevent addiction.

Treatment Options and Overcoming Addiction

There are various treatment options available to those who want to overcome addiction. These include group therapy, individual counseling, and medication-assisted treatment (MAT). 

MAT combines buprenorphine, naltrexone, and methadone to reduce cravings, withdrawal symptoms, and relapse risk. Cognitive behavioral therapy (CBT) can help people with SUDs identify and replace maladaptive thought patterns and behaviors.

Finally, support from family and friends is invaluable for those seeking treatment for substance use disorder. Family therapy, support groups, and 12-step programs can also be part of a successful recovery plan.

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Updated on April 3, 2024
14 sources cited
Updated on April 3, 2024
  1. Excessive Alcohol Use.” Centers for Disease Control and Prevention, 2022. 
  2. Today’s Heroin Epidemic Infographics.” Centers for Disease Control and Prevention, 2015.
  3. Ellgren, Maria, et al. “Adolescent cannabis exposure alters opiate intake and opioid limbic neuronal populations in adult rats.” American College of Neuropsychopharmacology, 2007.
  4. Griffin, Edmund A., et al. “Prior alcohol use enhances vulnerability to compulsive cocaine self-administration by promoting degradation of HDAC4 and HDAC5” Science Advances, 2017.
  5. Cigarette Smoking Gateway to Illegal Drug Use.” Johns Hopkins Bloomberg School of Public Health, 2000.
  6. Kandel, D. et al. “From Beer to Crack: Developmental Patterns of Drug Involvement.” American Journal of Public Health, 1993.
  7. Kandel, E.R., et all. “A Molecular Basis for Nicotine as a Gateway Drug.” The New England Journal of Medicine, 2014.https://www.nejm.org/doi/full/10.1056/NEJMsa1405092
  8. Kirby, Tristan, and Adam E. Barry. “Alcohol as a Gateway Drug: A Study of US 12th Graders.” Journal of School Health, n.d.
  9. Understanding Alcohol Use Disorder.” National Institute on Alcohol Abuse and Alcoholism, 2020.
  10. Is marijuana a gateway drug?” National Institute on Drug Abuse, 2021. 
  11. Nkansah-Amankra, Stephen, et al. ““Gateway hypothesis” and early drug use: Additional findings from tracking a population-based sample of adolescents to adulthood.” Preventative Medicine Reports, 2016.
  12. Ren, Michelle, et al. “Nicotine Gateway Effects on Adolescent Substance Use.” The Western Journal of Emergency Medicine, 2019.
  13. Volkow, Nora. “Recent Research Sheds New Light on Why Nicotine is So Addictive.” Scientific American, 2018.
  14. Kirby T, Barry AE. “Alcohol as a gateway drug: a study of US 12th graders.” J Sch Health, 2012.

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