The more research is released, the more legalization makes sense.

By Owen Poindexter / AlterNet

Back in the 1930s, the arguments to criminalize cannabis were bizarre and openly racist. The anti-pot crusader Harry Anslinger made all sorts of over-the-top claims, such as, “Marihuana is a short cut to the insane asylum. Smoke marihuana cigarettes for a month and what was once your brain will be nothing but a storehouse of horrid specters.”

Nowadays more than 100 million Americans say they’ve smoke pot, millions use cannabis regularly to treat illnesses and it is as legal as alcohol in two U.S. states. However, it remains illegal under federal law largely due to scare tactics ingrained in our society, which date back even prior to Anslinger.

Today, pot legalization opponents try a little harder to sound reasonable, but their claims don’t do much better than Anslinger’s under scrutiny. Recent studies have picked apart the justifications for criminalizing marijuana. Here are five of the most popular arguments against cannabis legalization that are easily undermined by objective data.

1. Pot leads to crime. If alcohol prohibition taught us anything it’s that prohibition itself leads to crime, not what is prohibited. While cannabis has shaken the psychotic Reefer Madness reputation over the years, the association between weed and crime is still alive and well in certain realms of the media, which are happy to present data without appropriate statistical caveats.

As for the studies that carefully and objectively examine their data, they find no association between cannabis and crime. A recent study in the journal PLOS One found that in states that legalized medical marijuana between 1990 and 2006 the crime rate either remained the same or decreased.

Another study looked at the Lambeth borough of London, which depenalized cannabis for 13 months in 2001-2002. The study found that this actually reduced other types of crime, because Lambeth police could focus their energy elsewhere.

These results fit with common sense. Cannabis has a range of effects on mood and behavior, but they don’t include violence, impulsivity or other traits that would turn otherwise law-abiding citizens into criminals.

2. The gateway theory. The gateway theory has long been the stock response of marijuana opponents to the notion that cannabis itself isn’t that bad for you. They falsely claim it leads to harder stuff, and insist that what starts with a joint ends with a heroin needle.

While it’s true that most users of hard drugs used marijuana and alcohol first, that doesn’t prove that cannabis use leads to harder drugs. Correlation does not equal causality—most heroin users have worn jeans at some point in their lives, but it’s unlikely that one leads to another.

But is it at least plausible that cannabis use creates a bridge to experimenting with more dangerous chemicals? The research says no.

A Rand Institute study using data collected from 1982-1994 found that drug use patterns in American youths can be explained without resorting to a gateway effect. People who are interested in mind-altering substances are likely to have tried pot, as it is the most popular and available illicit drug. This and other circumstantial factors related to drug availability and how old someone was when they first used cannabis were sufficient to explain drug use patterns. Since then, numerous peer-reviewed studies have been published, supporting Rand’s basic conclusions.

Holland provides a good natural experiment in the effects of cannabis use, as marijuana has been legal there for citizens since 1976. A Rand Corporation study from 2011, titled What Can We Learn From The Dutch Coffee Shop Experience? found no causal relationship between using cannabis and harder drugs. In fact, because legalization meant that people went to a coffee shop, not a dealer, to get high, Rand found that legal cannabis likely reduced rates of harder drug use.

3. Cannabis has no medicinal purpose. Even though it has been slain many times over at this point, this idea is worth mentioning because cannabis is still listed as a Schedule I substance by the U.S. government, which implies that the official federal stance is that it has no medical use and is “dangerous.” However, just the opposite is true according to the actual facts. Almost half the states in the U.S. already have some kind of medical marijuana law (20 plus Washington D.C.) and many more are likely to legalize medical marijuana in this year’s elections.

Cannabis has been shown to effectively treat a slew of conditions including seizure disorders (often quite dramatically), glaucoma, and symptoms related to chemotherapy. There is even evidence it can reduce certain types of cancerous tumors.

This is all well known and well documented, and yet cannabis remains a Schedule I drug. While it’s hard to find anyone who will still defend this policy, it remains the law of the land, and a major stumbling block on the path to reform.

4. Marijuana is addictive. The addiction claim has been contained over time, but never fully eradicated. Cannabis faces some guilt by association. How could alcohol, tobacco, heroin and cocaine all be clearly addictive and yet weed somehow isn’t?

Furthermore, with words like stoner and pothead in the lexicon, our culture has a firm grasp of the weed-dependent stereotype. When we think of marijuana addiction, an image comes to mind. He (usually a he), smokes pot and eats all day, is smelly and unshaven, watches too much TV and/or plays too many video games, and has a crappy job if he has a job at all. And sure, a lot of people actually do know someone like that, but the research show that, that someone is probably choosing their lifestyle rather than trapped in it by an actual addiction.

Regardless of how the addiction myth has stuck around, it is just that: a myth. The most commonly cited study on cannabis dependence declared that 4% of Americans 15-54 are dependent on cannabis. That’s compared to 24% who are dependent on tobacco and 14% on alcohol. Among users, they found that 9% of cannabis users who try it get hooked, as compared to 32% for tobacco and 15% for alcohol.

So cannabis seems to show some propensity for dependence, but for every dependent user, there are 10 who don’t develop that sort of issue, and this rate is better than that of popular legal drugs.

Furthermore, even the 9% figure is likely inflated. A subject in the oft-cited study was deemed “dependent” if they answered yes to at least three of seven questions. The survey included questions that would take a very different meaning with legal drugs than illegal, such as if “a great deal of time was spent in activities necessary to get the substance, taking the substance, or recovering from its effects.”

This study was conducted in the 1990s, before any state had recognized the medical use of cannabis, and acquiring it regularly involved considerable effort. Because of this, it’s not hard to imagine that users would experience “important social, occupational, or recreational activities given up or reduced because of use,” which was another criterion for dependence. It is quite possible the survey mistook habitual use for dependence in some cases.

We can be sure that cannabis is significantly less habit-forming than alcohol, and especially tobacco, and the degree to which people become dependent is probably overstated.

5. Pot makes users lazy.This idea is the most persistent: we rarely question the cultural belief that getting high saps one’s motivation. If there is any truth to that, it has been difficult to find in studies. What seems to be going on instead is that about 5-6% of the population has “amotivational syndrome,” and there is no significant difference in this between cannabis users and everyone else. One study looked at daily pot smokers and compared them to people who never touch pot. This found no significant difference between the two groups. There was a small difference in “subjective well-being” (how happy the subject says he or she is) favoring non-smokers, but the study authors ascribed much of this to medical conditions some of the subjects were taking cannabis to mitigate.

More than anything, the idea that stoners are lazy seems to be confirmation bias. We shrug off the examples that contradict that notion as special cases and nod sagely when our suspicions are confirmed. Furthermore, we fail to group unmotivated non-users with unmotivated users.

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As the stigma against cannabis research has disappeared and more good data has been made available, the arguments against legalization have fallen. If cannabis is a plant with legitimate medical uses, does not lead to crime or harder drugs, is not addictive and doesn’t make you lazy, what argument for prohibition remains?

If there are still legitimate reasons to keep cannabis criminalized, let’s talk about them, but if not, let’s cut out a major revenue stream of Mexico’s vicious drug cartels, grant easy access to medicine for people who need it, provide a major boost to our economy, and legalize already.

Owen Poindexter writes about politics and policy for Carbonated.tv. Follow him on Twitter at @Owen_Poindexter.