So what happened? Overall alcohol consumption did decrease a bit, but the country saw a dramatic increase in organized crime from all the black market distilleries that popped up both in major cities and rural communities. The problem was that the ordinary citizens didn’t really believe the propaganda the legislators ate up. They still wanted their afternoon cocktails. The end to Prohibition finally came when a wealthy Republican named Pauline Sabin (that’s right, a woman) brought to light the hypocrisy of her Prohibitionist colleagues who were “dry” by day and sauced by early evening. Sabin wasn’t able to gather support from the Republicans so she turned to the Democrats and Catholics who eagerly supported a repeal.

A similar sort of movement has been occurring over the last decade in regard to the legalization of marijuana. There is strong evidence that marijuana can provide long-term palliative care for patients in significant pain. Among the most commonly cited benefits is its ability to reduce nausea and vomiting and stimulate hunger in chemotherapy and AIDS patients. Other less established benefits of the drug include treatment of premenstrual syndrome, unintentional weight loss, neurogenic pain, movement disorders, asthma and glaucoma. The FDA reported that between 1997 and 2005, zero deaths were caused by primary use of marijuana. These findings have led to the drug’s legalization for medicinal use in many states. These laws have appeared to provide great benefits to patients. One of my close friends, an ER physician and medicinal marijuana prescriber in Michigan, adamantly proclaims that the pain relief provided by prescription-strength marijuana matches or beats the relief provided by highly addictive narcotics. The only different, he says, is that patients cease their drug-seeking behavior and learn to maintain a stable level of comfort.

Of course, studies have demonstrated some drawbacks to marijuana use including negative effects on intelligence , memory , respiratory function and higher incidence of mental disorders among users, which include schizophrenia , psychosis and depression . But it isn’t clear that the incidence of these problems exceeds the incidence we would expect to see with use of other recreational drugs such as alcohol. At this point, all we know is that marijuana use does appear to have negative psychological effects if used during young adulthood. But many researchers question the methodology used in these studies and, even if sound, these results haven’t been reliably reproduced in older populations.

Although it’s questionable whether marijuana is a gateway drug, it’s looking unlikely. Just like most law-breaking anti-prohibitionist home brewers didn’t progress to hitting the opium pipe, most marijuana smokers don’t find themselves on a street corner looking to score some crack rock. Most marijuana users just aren’t interested in the hardcore stuff. But what we do find is that recreational users do turn to synthetic variants that can be quite dangerous. Commonly known by their street names “K2” or “Spice,” these drugs are not actually derived from marijuana plants, but provide a very similar high. These drugs recently became illegal Title XI of the FDA Safety and Innovation Act after they were linked to symptoms such as agitations, nausea, vomiting, rapid heartbeat, elevated blood pressure, tremor, seizures, hallucinations, paranoid behavior, and non-responsiveness. A recent study showed that consumption of synthetic marijuana was the cause of 11,406 of the 4.9 million drug-related emergency department visits in 2010. Over 75 percent of visits were made by people between the ages of 12 to 29, but the average age of people admitted for synthetic marijuana-related illness was 6 years younger than those admitted for natural marijuana-related illness.

The typical response of researchers to these types of reports is to stress the importance of cracking down on illegal production of synthetic marijuana and reiterate the dangers of drug abuse to our youth—as if we weren’t doing that before. We act as though these types of findings give us new insight into the dangers of drug abuse even though all they demonstrate is that when denied something they know to be relatively harmless, youths turn to something they mistakenly believe to be equally harmless. I am not suggesting that all drugs should be legalized, for many like cocaine and methamphetamine are highly addictive and have extremely negative effects over the long term. What I am suggesting is that we question whether the evidence against the legalization of marijuana really stands up to its purported benefits. Maybe legalization of marijuana would provide those 11,406 people with a level of access to a drug they couldn’t avoid abusing. Maybe a good chunk would suffer from minor cognitive deficits preventing them from winning a Nobel Prize. But none of them would have landed in the hospital.