The
gateway drug theory (also called
gateway theory,
gateway hypothesis and
gateway effect) is the hypothesis that the habitual use of less deleterious drugs may lead to a future risk of using more dangerous hard drugs and crime.
The gateway drug theory is often attributed to the use of these 3 drugs
- Tobacco
Tobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as an organic pesticide, and in the form of nicotine tartrate it is used in some medicines. In consumption it most commonly appears in the forms of smoking, chewing, snuffing, or...
- Alcohol
An alcoholic beverage is a drink that contains ethanol . Alcoholic beverages are divided into three general classes: beers, wines, and spirits....
- Cannabis
Cannabisalso known as marijuana or marihuana, and ganja , among many other namesrefers to any number of preparations of the Cannabis plant intended for use as a psychoactive drug...
While some research shows that many hard drug users used cannabis or alcohol before moving on to the harder substances, other research shows that some serious drug abusers have used other drugs before using cannabis or alcohol.
The former is particularly evident in individual drug-abuse histories which tend to show that "hard drug" users do progress from one drug to another.
The
gateway drug theory (also called
gateway theory,
gateway hypothesis and
gateway effect) is the hypothesis that the habitual use of less deleterious drugs may lead to a future risk of using more dangerous hard drugs and crime.
The gateway drug theory is often attributed to the use of these 3 drugs
- Tobacco
Tobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as an organic pesticide, and in the form of nicotine tartrate it is used in some medicines. In consumption it most commonly appears in the forms of smoking, chewing, snuffing, or...
- Alcohol
An alcoholic beverage is a drink that contains ethanol . Alcoholic beverages are divided into three general classes: beers, wines, and spirits....
- Cannabis
Cannabisalso known as marijuana or marihuana, and ganja , among many other namesrefers to any number of preparations of the Cannabis plant intended for use as a psychoactive drug...
While some research shows that many hard drug users used cannabis or alcohol before moving on to the harder substances, other research shows that some serious drug abusers have used other drugs before using cannabis or alcohol.
The former is particularly evident in individual drug-abuse histories which tend to show that "hard drug" users do progress from one drug to another. Nonetheless, these histories and research do not indicate a causal relationship between the early uses and the later uses and, therefore, do not confirm the gateway theory.
Cannabis
Some scientific studies show that the consumption of
cannabisCannabisalso known as marijuana or marihuana, and ganja , among many other namesrefers to any number of preparations of the Cannabis plant intended for use as a psychoactive drug...
can possibly predict a significant higher risk for the subsequent use of other "harder" illicit drugs, while other studies show that it cannot. Two recent studies are from
University of PittsburghThe University of Pittsburgh, commonly referred to as Pitt, is a state-related research university located in Pittsburgh, Pennsylvania, United States. Founded as Pittsburgh Academy in 1787 on what was then the American frontier, Pitt is one of the oldest continuously chartered institutions of...
's
School of PharmacyChartered in 1878, the University of Pittsburgh's School of Pharmacy is the oldest of the University of Pittsburgh's schools of the health sciences...
, and from Dr. Michael Lynskey.
Study of Australian Adolescents (8 years)
A stratified, random sample of 1,943 adolescents was recruited from secondary schools across Victoria,
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the continental mainland , the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans...
at age 14–15 years. This cohort was interviewed on eight occasions until the age of 24–25 years. At age 24 years, 12% of the sample had used amphetamines in the past year, with 1%–2% using at least weekly. Young adult amphetamine use was predicted strongly by adolescent drug use and was associated robustly with other drug use and dependence in young adulthood. Associations were stronger for more frequent users. Among young adults who had not been using amphetamines at age 20 years, the strongest predictor of use at age 24 years was the use of other drugs, particularly cannabis, at 20 years. Those who were smoking cannabis at the age of 15 were as much as 15 times more likely to be using amphetamines in their early 20s.
Study of rats
In 2006, the Karolinska Institute in
SwedenSweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe...
used twelve rats to examine how adolescent use of cannabis affects subsequent abuse of other illicit drugs. The study gave six of the twelve "teenage" (28–49 days old, or 6.6–10.4 in human years) rats a small dose of
THCTetrahydrocannabinol , also known as delta-9-tetrahydrocannabinol , Δ
1-THC , or dronabinol, is the main psychoactive substance found in the Cannabis plant....
, reportedly equivalent to one cannabis joint smoked by a human, every three days. The rats were allowed to administer
heroinHeroin, or diacetylmorphine , also known as diamorphine , is a semi-synthetic opioid drug synthesized from morphine, a derivative of the opium poppy. It is the 3,6-diacetyl ester of morphine...
by pushing a lever and the study found the rats given THC took larger doses of heroin.
The institute examined the brain cells in the rats and found THC alters the opioid system that is associated with positive emotions, which lessens the effects of
opiateIn medicine, the term opiate describes any of the narcotic opioid alkaloids found as natural products in the opium poppy plant, as well as many semisynthetic chemical derivatives of such alkaloids.-Overview:...
s on rat's brain and thus causes them to use more heroin. Paul Armentano, policy analyst for
NORMLThe National Organization for the Reform of Marijuana Laws is a Washington, D.C.-based non-profit organization in the United States whose aim is to "move public opinion sufficiently to achieve the repeal of cannabis prohibition so that the responsible use of this drug by adults is no longer...
, claimed because the rats were given THC at the young age of 28 days, is impossible to extrapolate the results of this study to humans. Also, cannabis exposed adult rats, despite being desensitized to heroin, were in another study, no more likely to get addicted than the controls.
Studies not in favor of the gateway theory
In 1999, a study by the Division of Neuroscience and Behavioral Health at the
Institute of MedicineThe Institute of Medicine , one of the United States National Academies, is a not-for-profit, non-governmental American organization chartered in 1970 as a part of the United States National Academy of Sciences. Its purpose is to provide national advice on issues relating to biomedical science,...
entitled "Marijuana and Medicine: Assessing the Science Base," found no evidence of a link between cannabis use and the subsequent abuse of other illicit drugs on the basis of its particular physiological effect.
Mathematical Model
In December 2002, a study by
RANDThe RAND Corporation is a nonprofit global policy think tank first formed to offer research and analysis to the United States armed forces by Douglas Aircraft Company and currently financed predominantly by the U.S. government, a private endowment, predominantly pharmaceutical corporations,...
regarding if cannabis use results in the subsequent use of
cocaineCocaine is a crystalline tropane alkaloid that is obtained from the leaves of the coca plant. The name comes from "coca" in addition to the alkaloid suffix -ine, forming cocaine. It is a stimulant of the central nervous system and an appetite suppressant...
and
heroinHeroin, or diacetylmorphine , also known as diamorphine , is a semi-synthetic opioid drug synthesized from morphine, a derivative of the opium poppy. It is the 3,6-diacetyl ester of morphine...
was published in the British Journal of Addiction, a peer-reviewed scientific publication. The researchers created a mathematical model simulating adolescent drug use. National rates of cannabis and hard drug use in the model matched survey data collected from representative samples of youths from across the United States; the model produced patterns of drug use and abuse. Andrew Morral, associate director of RAND's Public Safety and Justice unit and lead author of the study stated:
Study on American Adolescents (12 years)
In December 2006, a 12 year gateway drug hypothesis study on 214 boys from ages 10–12 by the
American Psychiatric AssociationThe American Psychiatric Association is the main professional organization of psychiatrists and trainee psychiatrists in the United States, and the most influential worldwide. Its some 38,000 members are mainly American but some are international...
was published in the
American Journal of PsychiatryThe American Journal of Psychiatry is the official journal of theAmerican Psychiatric Association , the 3rd psychiatric journal by impact factor, and the most widely read and cited psychiatric journal in the world. It covers topics on biological psychiatry, treatment innovations, and forensic,...
. The study concluded adolescents who used cannabis prior to using other drugs, including alcohol and tobacco, were no more likely to develop a substance abuse disorder than subjects in the study who did not use cannabis prior to using other drugs.
One reason the risk factor for abusing drugs in cannabis users is higher is because few people try hard drugs prior to trying cannabis, not because cannabis users increasingly try hard drugs such as amphetamines. Further research has shown that people with a disposition to resort to cannabis use are more likely to live longer and healthier lives than users of other "social drugs" such as alcohol.
Tobacco
According to the
NIDAThe National Institute on Drug Abuse is a United States federal-government research institute whose mission is to "lead the Nation in bringing the power of science to bear on drug abuse and addiction."-History:...
, "People who abuse drugs are also likely to be cigarette smokers. More than two-thirds of drug abusers are regular tobacco smokers, a rate more than double that of the rest of the population."
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