Reprinted with permission from Marijuana Legalization: What Everyone Needs to Know by Jonathan P. Caulkins, Angela Hawken, Beau Kilmer, Mark A. R. Kleiman, published by Oxford University Press © 2012 Oxford University Press.
If alcohol is more dangerous than marijuana, what's the logical justification for one being legal and the other illegal?
If we were making laws for a planet whose population had never experienced either marijuana or alcohol, and we had to choose one of the two drugs to make available, there would be a strong case for choosing marijuana, which has lower organic toxicity, lower addictive risk, and a much weaker link with accidents and violence.
But that's not the planet we inhabit. Here on this planet, alcohol has been an ingrained part of many cultures since the Neolithic revolution (which may have been driven in part by the discovery that grain could be brewed into beer). People have used cannabis plant products for thousands of years, but its widespread use as an intoxicant in the United States is a phenomenon of the last hundred years. Even today only about one in sixteen American adults used marijuana at all in the course of a typical year; for alcohol, that figure is more than half.
History matters. Custom matters. Practicality matters. Even if there were public support for it, going back to Prohibition wouldn't work—without a truly ferocious degree of law enforcement—precisely because centuries of tradition and decades of marketing have left alcohol use a deeply ingrained feature of most social systems outside the Islamic world.
The technical term for this is "path dependence." If alcohol had just been invented and no one was yet using it, it would go straight into Schedule I: high potential for abuse, and no accepted medical value. And that ban might make sense. But once there is an established user base, prohibition becomes impractical. Marijuana is not, or at least not yet, equally entrenched.
It's true that the arguments for maintaining marijuana prohibition also point strongly toward tighter controls on alcohol: higher taxes, limits on marketing, bans on sales to people convicted of driving drunk or other crimes committed under the influence. So it's fair to mock the "drug warriors" who worry about every drug except the one that does the most damage. But, by the same token, advocates of marijuana legalization who point to the horrible amount of damage alcohol does are pointing to precisely the strongest argument for maintaining marijuana prohibition: the one drug we legalized is the most harmful of all despite all our efforts at regulation.
Can it be defensible to support legalizing marijuana but not other drugs?
There is no logical reason to apply the same policies to all psychoactives. Most people support prohibiting crack but not caffeine, and that is an entirely defensible position.
A key reason someone might be more willing to legalize marijuana than the other major drugs is that legalizing marijuana is less risky. Relative to the other major drugs, marijuana enforcement is already lax, and as a result prices are much less inflated. Also, social disapprobation is rather modest, and dependence is easier to break. So legalizing marijuana is far less likely to produce highly problematic increases in dependence than legalizing any of those other substances.
Can two reasonable people sensibly disagree about marijuana legalization?
Even if we could accurately estimate all the gains and losses—which we can't—there's no reason two people holding different values couldn't reasonably disagree on whether that change represented progress. One person might care enormously about reducing dependence for the sake of the children of those who are dependent; another might place greater emphasis on reducing street violence or incarceration. Those two people could make the same predictions about the likely consequences of legalization but reach different conclusions about its desirability.
Can marijuana use lead to dependence or addiction?
Yes, but even among frequent marijuana users only a minority suffers from a substance abuse disorder.
"Addiction" is no longer a term in medical use; the technical terms are "abuse" and "dependence," where dependence is the more severe condition. Sometimes "addiction" is used to refer to dependence in its chronic, relapsing form.
Abuse and dependence are defined by the Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association, currently in its fourth edition (and thus called DSM-IV). To simplify, the DSM-IV definition of drug abuse is continued use of a substance in the face of adverse consequences. Dependence is defined as current use meeting three or more of the conditions:
- Tolerance (needing more to get same effect)
- Withdrawal (cessation causes a characteristic set of symptoms)
- Using more than intended
- Wanting to or having tried unsuccessfully to cut down on use
- Spending considerable time obtaining and using the substance
- Interference with important work, social, or other activities
- Continued use despite knowledge of adverse consequences
Survey responses suggest that more than 8 million current marijuana users meet criteria 4 and 5; far fewer mention the other issues. For example, only 1.5 million report that their marijuana use is causing problems with work / school / home and with family or friends.
Taking all the criteria into account, the self-report data suggest that 2.7 million Americans met clinical criteria for marijuana dependence in 2009, and another 1.7 million met the criteria for abuse, so 4.4 million met the criteria for abuse or dependence (that's 1.7 percent of the population aged 12 and older).
Estimates from Europe and Australia also find rates of marijuana abuse and dependence in the general population between 1 percent and 2 percent. This relatively small group accounts for a considerable share of total consumption.
But regular marijuana use does not necessarily indicate dependence. Only about 30 percent of those who are estimated to have used on more than half the days in the last year self-report symptoms that suggest a diagnosis of abuse or dependence. The corresponding figure for cocaine is 88 percent.
Someone who uses cocaine every other day or more often is probably cocaine dependent; someone who uses marijuana every other day or more often is probably not cannabis dependent. In this regard, marijuana resembles alcohol more than it does the "hard" drugs.
This excerpt originally appeared on huffingtonpost.com.
This commentary appeared on Huffington Post on July 12, 2012