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

[MrLeRoy]

and MLR "You're a better man than I am

I hate compliments---they really take the edge off the flame wars. ;-)

[unspun]

There are so many people with so many positions on all this stuff anyway, that it's a free for all each time. Yeee - hooo !!!

That's about the size of it---so knocking somebody for posting a tangent is probably pointless, and knocking them for an on-point reply to someone else's tangential post is downright silly.

If everyone in FR followed that discipline, we might have some very short "conversations" ...or not!

I would like to attempt to raise my horror threshhold regarding opinions from FReepers and pick up the topic of DRUGS, from recreational mind-manglers, to pharmaceuticals, taking up some substantial discussions about pragmatic solutions (the kind of thing I naively hoped might occur a couple weeks ago on that nonviolent drug offenders and release from prison post).

It could be (gulp) profitable to (gulp) confer about the issue of what policies could look like in a more rational America. Perhaps I could pick an article and start a thread in "RLC Liberty Caucus" -- that should be a nice quiet corner.

Anyone interested?

My Caveat: I would hope we could keep the range of opinion from just flying off into "no legislation, none of the time." That gets me wanting to join the Union troops and fight for the blue! If capital "L" Libertarians flood it with their favorite flaming fodder, it would crash and burn. Personnally, not looking for the lazy man's vision of utopia, nor the idea that if we have trouble with enforcing a law, just write it off like Worldcom, and who needs laws anyway? `-> That would just show that those who post for drug law liberalization are being disserved by an Totalibertarian assault.

I'm not really optimisitc about this, for those attracted to drug threads*, but it would be interesting to have a discussion about what might promote our welfare and our liberties significantly better. Once again, neither (actual) authoritarianism, nor anarchy --and the authoritarianism that inevitably follows chaos-- are quite the aim.

If we could have such a discussion, I might even invite tpaine. Well, afterward, anyway, eh tp?

I suppose it could be thought of as a test to see ""we"" could come up with rational answers for our People's governance, per this matter. Once again, not optimistic, but maybe two competing consensi(sp?) could develop. Maybe.

________________________________
*Come to think of it, I used to know someone who wore drug threads -- why "freaks" used to wear all those patches, don'tchaknow. Evidence that yes, there is something in their jeans.

[cinFLA]

This is easy. Other countries have decriminalized marijuana. Since then, has harder drug use increased in those countries?

Yes. This is easy.

[Hebrews 11:6]

What Scripture do you believe supports those claims?

Excellent question, one worthy of an essay exam in a Christian college's American History or Logic course. The "B" and "C" students would attempt to answer it, whereas the "A" students would spot the trap and throw it back into the professor's face, thusly:

They claimed it was "self-evident," thus requiring no Scriptural support. That puts the burden back onto those challenging their decision, to prove, either self-evidently or from Scripture, that liberty is not a God-given unalienable right and that they do not have the right to throw off a despot's rule.

[unspun]

And...?

[justshe]

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[tpaine]

"If we could have such a discussion, I might even invite tpaine. Well, afterward, anyway, eh tp?"
-unspun-

How droll.
You claim to want "substantial discussions about pragmatic solutions", but every time the obvious & constitutional solution is mentioned: --
-- That of restoring reasonable regulations [not prohibitions] at state/local levels, -- you simply deny that this is acceptable.

[tacticalogic]

I suppose it could be thought of as a test to see ""we"" could come up with rational answers for our People's governance, per this matter.

I'm game, but I do have a question. Any particular reason you've limited the range of allowable discussion in one direction only?

[unspun]

I'm game, but I do have a question. Any particular reason you've limited the range of allowable discussion in one direction only?

Because the throw weight of um... stict constructionalist... posters in these drug threads already means that it will be virtually impossible to hold a discussion that allows the present drug policy to be defended in its entirity.

At least not without constitutional amendment.

100% current federal policy is out of bounds, as is total laissez faire. (I suppose I could have just said that, but we're not in that thread yet;-)

[unspun]

but every time the obvious & constitutional solution is mentioned: -- -- That of restoring reasonable regulations [not prohibitions] at state/local levels, -- you simply deny that this is acceptable.

Well, I don't think you'll find unanimous agreement on your interpretation of the limitations of state governments, even among more constitutionally strict and substance-liberal posters.

[unspun]

But please feel free.

[tpaine]

"If we could have such a discussion, I might even invite tpaine. Well, afterward, anyway, eh tp?"
-unspun-

How droll.
You claim to want "substantial discussions about pragmatic solutions", but every time the obvious & constitutional solution is mentioned: --
-- That of restoring reasonable regulations [not prohibitions] at state/local levels, -- you simply deny that this is acceptable.
147 tpaine


Well, I don't think you'll find unanimous agreement on your interpretation of the limitations of state governments, even among more constitutionally strict and substance-liberal posters.
"But feel free"

How comical. You've made my point once again.
Do you want pragmatic discussion or unanimous agreement? -- Obviously, in your own words just above, you seek the latter.

Run along now and find someone else to play word games. - Roscoe has vast experience in that silly art.

[A CA Guy]

Those for legalizing pot here are mostly of the drug culture I think to begin with and are using a political party as a way to legalize their stash unspun.
They don't frame the issue as a need to change the method of enforcing the restrictions of illegal drugs, instead they want to open the door to all vices at ones leisure. That in no way seems a conservative trait.

[A CA Guy]

"it is not marijuana use but individuals' opportunities and unique propensities to use drugs that determine their risk of initiating hard drugs."

What a great all inclusive paragraph that shows why there needs to be illegal drug use laws throughout America.

[MrLeRoy]

Those for legalizing pot here are mostly of the drug culture I think to begin with and are using a political party as a way to legalize their stash unspun.

Thanks for the sleazy ad hominem attack---it exposes the emptiness of the Drug Warrior position.

[MrLeRoy]

They claimed it was "self-evident," thus requiring no Scriptural support.

Works for me---it's self-evident that a ruler attempting to usurp an individual's stewardship rights over his own body is not acting as God's servant and need not be obeyed.

[headsonpikes]

Bumping my post #78.

Feel free to accept that post as my initial contribution to your proposed debate.

The so-called WOD is based on a rationale of 'established' knowledge about human nature.

Abandon the scientific pretense and a free-ranging debate about the relation between state and citizen becomes possible. The hysterical response of 'authorities' to the use of 'drugs' is merely one egregious example of the modern statist trend towards 'human resource management'.

See post #78.

All IMNSHO. ;^)

[tacticalogic]

whereas the "A" students would spot the trap and throw it back into the professor's face, thusly:

They claimed it was "self-evident," thus requiring no Scriptural support.

And the professor would throw it right back at them noting that there is nothing that precludes a "self evident truth" from being supported by the scriptures.

[tacticalogic]

Those for legalizing pot here are mostly of the drug culture I think to begin with

At least you recognize and admit your own pre-conceptions. Now you have to realize that as long as you hold on to them, your views are suspect in the context of a rational debate.

[unspun]

Works for me---it's self-evident that a ruler attempting to usurp an individual's stewardship rights over his own body is not acting as God's servant and need not be obeyed.

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

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