A New York Times article on Sunday discussed the debate over whether more and more potent types of cannabis affect the levels of addiction to the drug. This particular issue has become part of the larger debate over whether marijuana should be legalized or decriminalized.

Antidrug activists say that if the drug is legalized, more people will use it and addiction levels, made worse by the increased potency, will rise too. Legalization advocates note that pot addiction is not nearly as destructive as, say, abuse of alcohol. What would be the effect of legalization or decriminalization on marijuana abuse and addiction?

Roger Roffman is a professor of social work at the University of Washington.

Marijuana dependence occurs in 9 percent of Americans who have ever used the drug, and between 33 percent and 50 percent of those who smoke it daily. Approximately 3.6 million Americans are daily or near daily users. In 20 years of marijuana dependence counseling studies at the University of Washington, those who’ve sought help averaged 10 years of daily or near daily use and had unsuccessfully tried to quit more than six times.

There might be a big difference between legalization and decriminalization when it comes to the dependence issue.

Surveys indicate increasingly positive attitudes in the U.S. for liberalizing marijuana policies. Two ways of doing this are: (1) legalization, which would involve lawful cultivation and sale of marijuana, and (2) decriminalization, which would retain criminal penalties for cultivation and sale while removing them for possession of small amounts.

Will more people use marijuana and become dependent if marijuana is decriminalized? Probably not. A number of U.S. studies tell us decriminalization would not likely have an effect on the rates of marijuana use by adults or adolescents.

What if marijuana is legalized? No one can say for certain. Using one country’s reform example to estimate what would happen in another is very risky. How countries differ (cultural, social, political, economic) makes a big difference.

However, the Dutch “coffee shops” example might give us a little insight. The de facto legalization policy in the Netherlands did not, in itself, affect rates of marijuana use among adults or young people. But rates of use among young people increased when the number of coffee shops increased and the age of legal access was 16. Then these rates declined when the numbers of coffee shops was reduced and the age of legal access became 18.

A cautious conclusion, as I see it, is that any consideration of legalization should include careful planning for how those who are most vulnerable to harm from marijuana use, children and adolescents, can be protected.

I support finding alternatives to criminal penalties for marijuana possession. Those penalties have costs (being jailed, having a criminal record, barriers to employment, loss of scholarships, to name a few) and may accomplish little in deterring use.

However, our debates need more honesty. Those favoring liberalizing marijuana policy ought to stop inferring that marijuana is harmless; it is not. Those who believe possession should remain a crime need to acknowledge that most adult occasional users are not harmed, and should be prepared to defend with data the belief that criminalizing possession is the best way to avoid harm.

Mitigating Dependence

Wayne Hall is a professor of public health policy at the School of Population Health at the University of Queensland in Australia.



What effect would marijuana legalization have on dependence?

Some people remain skeptical about whether marijuana dependence exists but let’s assume that it does and that it affects around 1 in 10 of those who use marijuana. The effects that legalization has on marijuana dependence depend critically on what we mean by the term.

Marijuana use increased in the Netherlands in the 1990s, but this was also the case in the rest of Europe.

If we mean replacing imprisonment with a fine as the penalty for using marijuana then legalization would have little effect on dependence. Evaluations of this policy in 11 U.S. states in the 1970s and 1980s found little or no effect on rates of use among adolescents and adults.

There is more debate about the effects of allowing a de facto legal marijuana market as the Netherlands has done since 1983 in tolerating the sale of small amounts of marijuana in coffee shops. Marijuana use increased in the Netherlands in the 1990s, but this was also the case in the rest of Europe, and policy analysts disagree about whether rates of use increased faster in the Netherlands than elsewhere.

If by legalization we mean making it legal to use, grow and sell marijuana then our task becomes more speculative because no modern country has adopted this policy. It seems common sense that legalizing marijuana use and sales would lead to more people using it regularly and this would probably mean more marijuana dependence.

Nonetheless it is difficult to say how much use may increase because there are options for reducing use under a legal market that are not now available. For example, we could tax marijuana to set the price at a level that discourages casual use, regulate its THC content, restrict sales to minors, include a health warning on packs and advise users on ways to reduce dependence risks (e.g. by using less than weekly). These possibilities make it difficult to predict the effect that a legal market would have on rates of marijuana dependence.

Marijuana dependence should be taken into account in considering whether we should legalize marijuana in any of these ways. But this concern also needs to be weighed against the costs of current policy, that is, the creation of perverse incentives to produce more potent marijuana, the widespread disregard of legal prohibition on marijuana use that could contribute to a decline in respect for law and policing; the unregulated access of minors to marijuana; and the social and economic costs of a large marijuana black market.

Not Your Grandfather’s Pot?

Mark A.R. Kleiman is a professor of public policy at U.C.L.A., the editor of the Journal of Drug Policy Analysis and the author of “Against Excess: Drug Policy for Results.” His new book, “When Brute Force Fails: How to Have Less Crime and Less Punishment,” will be published later this summer.



One of the standard arguments against the legalization of cannabis is that “this is not your grandfather’s pot”: cannabis, say the drug warriors, is much stronger now than it was a generation ago. It is, therefore, much more dangerous, and must remain prohibited.

Whatever we do about cannabis will leave us with most of the nation’s drug-related problems.

That argument is a few bricks shy of a full load. Here are some of those bricks.

1. The average gram of cannabis sold today contains much more Δ-9-trahydrocannabinol (THC) than the average gram sold in 1970, though there has always been some highly potent product available.

2. Emergency-room visits and treatment admissions related to cannabis have increased, though the number of self-reported cannabis users hasn’t.

3. If the only change were in potency as measured by THC content, users could (and do) compensate by smoking smaller quantities.

4. But contemporary cannabis also has a much higher ratio of THC (which tends to induce anxiety) to cannabidiol (CBD, which tends to relieve anxiety). That would be expected to create a higher rate of panic attacks.

5. Whether high-THC, high-ratio pot is also more habit-forming than other pot remains unknown. Increased treatment admissions might come from increased enforcement pressure against users. Or perhaps a cannabis habit is harder to live with than it used to be because the cannabis experience is more disturbing.

6. If cannabis were made legal, restrictions could be put both on potency and on the THC/CBD ratio. So rising potency makes no sense as an anti-legalization argument; if anything, less-potent legal pot would be expected to substitute for the more-potent pot that would remain illegal.

7. Any sort of flat-out legalization would risk a large increase in the number of very heavy users. A legal cannabis industry, like the legal alcohol industry, would derive more than half its revenue from people with diagnosable substance abuse disorders. Telling marketers they can get rich by creating disease is dangerous.

8. Instead we could choose a “grow your own” policy that would allow production for personal use or by small nonprofit cooperatives, but forbid commercial sales.

Cannabis policy is fascinating because so many people smoke the stuff, but whatever we do about cannabis will leave us with most of the nation’s drug abuse problems, which center on alcohol, and most of the nation’s drug-market and drug-enforcement problems, which center on cocaine, methamphetamine and heroin.

Lessons From the Dutch

Peter Reuter is a professor at the School of Public Policy and the Department of Criminology at the University of Maryland.



Experimenting with marijuana has long been a normal part of growing up in the U.S.; about half of the population born since 1960 has tried the drug by age 21. Perhaps one out of six has used it for a year or more. This statement is increasingly true of other Western countries such as Australia and Britain.

Over the last decade most of these countries have seen three trends; sharp increases in the number of marijuana users seeking treatment, in the potency of the marijuana consumed and in the number of arrests. For example, in the European Union the number of people entering treatment programs for marijuana dependence tripled between 1999 and 2005. In the U.S., the potency of seized marijuana has steadily increased since the late 1970s, while arrests for simple possession have tripled since 1991 to 750,000.

Legalization in the U.S. might be a much more commercial matter than in pragmatic Holland.

Are these trends connected? Given that marijuana research is almost as scarce as drug-free communities, all that is available is moderately informed speculation. A recent book that I co-authored, “Cannabis Policy: Moving Beyond the Stalemate,” identifies five other factors that may play an influence in this. There is also no direct evidence that potency makes a difference to how much the drug hurts users’ health; most users titrate their dose with higher THC.

What would happen if the drug were legalized? The Dutch de facto legalization of sale through coffee shops is the closest available experience. The most striking observation is that marijuana use in that country is lower than in many other European countries and a lot lower than in the United States; 6 percent of 15- to 64-year-olds in Holland had used marijuana in the past year, compared to 11 percent in the U.S.

Legalization in the U.S. might be a much more commercial matter than in pragmatic Holland, where the government created a legally ambiguous regulatory system with minimal court oversight. The U.S. might find it hard to prevent producers from using their First Amendment rights to actively promote the drug. A way of avoiding this would be to remove prohibitions on growing for your own use and for gifts to others. No doubt there would still be a black market but it would allow access to marijuana without creating a full commercialization. Probably this would lead to a modest increase in the number of people who use the drug, which needs to be weighed against the elimination of 750,000 arrests for simple possession.

The Tobacco Precedent

Norm Stamper was Seattle’s police chief from 1994 to 2000. He is a member of Law Enforcement Against Prohibition and the author of “Breaking Rank: A Top Cop’s Exposé of the Dark Side of American Policing.”

Any law disobeyed by more than 100 million Americans, the number who’ve tried marijuana at least once, is bad public policy. As a 34-year police veteran, I’ve seen how marijuana prohibition breeds disrespect for the law, and contempt for those who enforce it.

Let’s examine arguments against legalizing marijuana: use and abuse would skyrocket; the increased potency of today’s marijuana would exacerbate social and medical problems; and legalization would send the wrong message to our children.