Using Marijuana May Not Raise the Risk of Using Harder Drugs (but look at alternative explanation)

RAND's Drug Policy Research Center ^ | December 2, 2002 | RAND's Drug Policy Research Center

[unspun]

Using Marijuana May Not Raise the Risk of Using Harder Drugs

Marijuana is widely regarded as a "gateway" drug, that is, one whose use results in an increased likelihood of using more serious drugs such as cocaine and heroin. This gateway effect is one of the principal reasons cited in defense of laws prohibiting the use or possession of marijuana. A recent analysis by RAND's Drug Policy Research Center (DPRC) suggests that data typically used to support a marijuana gateway effect can be explained as well by a different theory. The new research, by Andrew Morral, associate director of RAND Public Safety and Justice, Daniel McCaffrey, and Susan Paddock, has implications for U.S. marijuana policy. However, decisions about relaxing U.S. marijuana laws must necessarily take into account many other factors in addition to whether or not marijuana is a gateway drug.

Support for the Gateway Effect

Although marijuana has never been shown to have a gateway effect, three drug initiation facts support the notion that marijuana use raises the risk of hard-drug use:

• Marijuana users are many times more likely than nonusers to progress to hard-drug use.

• Almost all who have used both marijuana and hard drugs used marijuana first.

• The greater the frequency of marijuana use, the greater the likelihood of using hard drugs later.

This evidence would appear to make a strong case for a gateway effect. However, another explanation has been suggested: Those who use drugs may have an underlying propensity to do so that is not specific to any one drug. There is some support for such a "common-factor" model in studies of genetic, familial, and environmental factors influencing drug use. The presence of a common propensity could explain why people who use one drug are so much more likely to use another than are people who do not use the first drug. It has also been suggested that marijuana use precedes hard-drug use simply because opportunities to use marijuana come earlier in life than opportunities to use hard drugs. The DPRC analysis offers the first quantitative evidence that these observations can, without resort to a gateway effect, explain the strong observed associations between marijuana and hard-drug initiation.

New Support for Other Explanations

The DPRC research team examined the drug use patterns reported by more than 58,000 U.S. residents between the ages of 12 and 25 who participated in the National Household Surveys on Drug Abuse (NHSDA) conducted between 1982 and 1994.^[1] Using a statistical model, the researchers tested whether the observed patterns of drug use initiation might be expected if drug initiation risks were determined exclusively by

• when youths had a first opportunity to use each drug

• individuals' drug use propensity, which was assumed to be normally distributed^[2] in the population

• chance (or random) factors.

To put it another way, the researchers addressed the question: Could the drug initiation facts listed in the first section of this brief be explained without recourse to a marijuana gateway effect?

Figure 1—Probabilities of Initiating Hard Drugs, Marijuana Users and Nonusers

The research team found that these associations could be explained without any gateway effects:

• The statistical model could explain the increased risk of hard-drug initiation experienced by marijuana users. Indeed, the model predicted that marijuana users would be at even greater risk of drug use progression than the actual NHSDA data show (see Figure 1).

• The model predicted that only a fraction of hard-drug users would not have tried marijuana first. Whereas in the NHSDA data 1.6 percent of adolescents tried hard drugs before marijuana, the model predicted an even stronger sequencing of initiation, with just 1.1 percent trying hard drugs first.

• The modeled relationship between marijuana use frequency and hard-drug initiation could closely match the actual relationship (see Figure 2).

The new DPRC research thus demonstrates that the phenomena supporting claims that marijuana is a gateway drug also support the alternative explanation: that it is not marijuana use but individuals' opportunities and unique propensities to use drugs that determine their risk of initiating hard drugs. The research does not disprove the gateway theory; it merely shows that another explanation is plausible.

Figure 2—Probabilities of Hard-Drug Initiation, Given Marijuana Use Frequency in the Preceding Year

Some might argue that as long as the gateway theory remains a possible explanation, policymakers should play it safe and retain current strictures against marijuana use and possession. That attitude might be a sound one if current marijuana policies were free of costs and harms. But prohibition policies are not cost-free, and their harms are significant: The more than 700,000 marijuana arrests per year in the United States burden individuals, families, neighborhoods, and society as a whole.

Marijuana policies should weigh these harms of prohibition against the harms of increased marijuana availability and use, harms that could include adverse effects on the health, development, education, and cognitive functioning of marijuana users. However, the harms of marijuana use can no longer be viewed as necessarily including an expansion of hard-drug use and its associated harms. This shift in perspective ought to change the overall balance between the harms and benefits of different marijuana policies. Whether it is sufficient to change it decisively is something that the new DPRC research cannot aid in resolving.

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^[1]In subsequent years, respondents have not been asked about their first opportunity to use various drugs.

^[2]That is, some people have a high or low propensity, but most people have a propensity near the middle of the range.

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RB-6010 (2002)

RAND research briefs summarize research that has been more fully documented elsewhere. This research brief describes work done in RAND's Drug Policy Research Center, a joint endeavor of RAND Public Safety and Justice and RAND Health. The research is documented in "Reassessing the Marijuana Gateway Effect" by Andrew R. Morral, Daniel F. McCaffrey, and Susan M. Paddock, Addiction 97:1493-1504, 2002.

Abstracts of RAND documents may be viewed at www.rand.org. Publications are distributed to the trade by NBN. RAND^® is a registered trademark. RAND is a nonprofit institution that helps improve policy and decisionmaking through research and analysis; its publications do not necessarily reflect the opinions or policies of its research sponsors.

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RAND Home Page

[unspun]

You can see how I word it, in the thread (don't have it up, yet).

[MrLeRoy]

And using the same pretext of natural law, I'd cite A.Lincoln, that no one has the right to do what is wrong.

How does Lincoln's claim derive from natural law?

That's why we have republican government, not government by tribunal.

What does that have to do with having (or not) the right to do wrong?

[A CA Guy]

My "pre-conceptions" as you call them have come to me lately after years of reading Libertarians views, their hearts desires are unmasked everywhere and it wasn't pretty.

[MrLeRoy]

My "pre-conceptions" as you call them have come to me lately after years of reading Libertarians views

You determined that many of them were drug users by reading their views in favor of legalizing drugs? Spare us your stupid lies.

[tacticalogic]

My "pre-conceptions" as you call them have come to me lately after years of reading Libertarians views, their hearts desires are unmasked everywhere and it wasn't pretty.

If everyone who is in favor of legalization were a Libertarian, you might have a valid argument.

[A CA Guy]

Wouldn't a Drug Warrior be one for drugs?

I am pro drug law enforcement to reduce damage done by the idiots who would get themselves in trouble and others in danger with illegal drugs.
The politics of anarchy which Libertarians want to push on common sense America won't fly Mr.LR

Just say NO to illegal drugs and their growth which destroys the Spirit of people.
Libertarians are mostly Pro-Addict Warriors by the way here at FR Mr.LR, aren't they? Not something to be proud of.

[MrLeRoy]

Wouldn't a Drug Warrior be one for drugs?

No, it's one who conducts or supports the War On (Some) Drugs.

The politics of anarchy which Libertarians want to push

Libertarians are not anarchists.

Libertarians are mostly Pro-Addict Warriors by the way here at FR Mr.LR, aren't they?

I have never seen a "pro-addict" post on FR.

[unspun]

-self evident truths.

-such things are for a free people to make careful, respectful, constitutional decisions about, not for a tribunal interpreting a strict set of rules to protect the most possible liberties.

[MrLeRoy]

a tribunal interpreting a strict set of rules to protect the most possible liberties

Who here has called for such a tribunal?

[jodorowsky]

Who here has called for such a tribunal?

No kidding, that is so unrealistic. Everybody knows you need an iron-willed Extraordinary Powers Commission and a massive program of political hygiene before the tribunals can be implemented. Read Locke.

[unspun]

That is effectively what Libertarianism does. It restricts government to a tribunal in theory, where the ideal is personal liberty.

[MrLeRoy]

That is effectively what Libertarianism does. It restricts government to a tribunal in theory

That's preposterous.

[headsonpikes]

Yeah, Mr. Guy...put me down as a 'Pro-Addict Warrior'.

I believe addicts have the same legal status as yourself.

Be very careful when you set out to strip rights from those you consider 'unclean'.

You may well be next, no matter how abject your attitude towards authority.

Hitler started filling the camps with the addicts and queers, not the Jews.

I'm not sure why I even bother responding to your parrotting of slogans; it's not as if you have any belief in your own God-given powers of reason.

[Hebrews 11:6]

Do you think they should have supported it with Scriture, rather than claiming their justification was self-evident? Why do you suppose they acted as they did? You don't suppose it was because there actually is no Scriptural support, do you?

[tacticalogic]

Do you think they should have supported it with Scriture, rather than claiming their justification was self-evident? Why do you suppose they acted as they did? You don't suppose it was because there actually is no Scriptural support, do you?

No, I don't think they should have. They were establishing a secular government, and their experience with English rule had taught them to avoid government based on theology. As far there not being any scripture to support it, I guess it depends on your interpretation.

Render unto God what is God's. Render unto Ceasar what is Ceasar's.

If Ceasar is due an ass kicking, then God wants us to give it to him.

[Hebrews 11:6]

If Ceasar is due an ass kicking, then God wants us to give it to him.

LOL

[Mike4Freedom]

That in no way seems a conservative trait.

Well, that depends on your definition of "conservative". I always thought that modern conservatives wanted, first and foremost, to restore the constitution. That would shut down all sorts of social spending and control exerted by the Federal government. This would come from strict enforcement of the Bill of Rights, specifically the Tenth Amendment.

The Tenth forbids the Feds from doing anything not specifically listed in Article 1/Section 8 or added by amendment. That does more than say no Federal input to welfare, education, SS, and so on. It also means no Federal control of drugs. Just like it once meant no Federal control of alcohol without a specific amendment to change the list.

So you see, the Libertarians are more conservative than you on this issue.

[unspun]

A late response, with something I've just run across....

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American Enterprise "Is America Turning A Corner?" (conservative social values)Issue: Jan, 1999, "A New Era of Civic Virtue Is Dawning," Stephen Moore

Over the past five to ten years a remarkable cultural turnabout has occurred. With few exceptions, the same social statistics that deteriorated in the 1960s, '70s, and early '80s, have improved, or at least plateaued.

Since 1990, the abortion rate has dropped, illegitimate births have declined, welfare use has fallen precipitously, as has crime. It's virtually impossible to pick up a newspaper and not hear a story of social improvement. A few 1998 examples:

* "The government's survey of drug use finds that in 1996 only 18.3 percent of teens between 12 and 17 had smoked in the past month, the lowest since 1985." --Washington Post

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And I've seen it posted how national drug policies have been a terrible flop. Hm.

[unspun]

Of course, the Scriptures also testify that God's testimony is self evident (Romans 1&2).

Also, be careful who's getting kicked! In America, Caesar is us folk!

[rb22982]

Just because something skyrockets during a period of sex, drugs and rock and roll, and then drops some off its peak doesnt prove that locking people up suddenly worked after 70 years of failing to reduce use. Also welfare use dropped do to 1) the booming 90s economy and 2) welfare reform. Nothing to do with the drug war,and illegitmate sex has to do with 1) 60s and 70s are over 2) people use birth control much more frequently now.