Marijuana Laws and Marijuana Use -- What the National Research Council Said

One of the arguments raised regularly by opponents of marijuana law reform is the claim that any lessening of penalties will lead to higher rates of marijuana use, and from that all sorts of terrible consequences will flow. This argument has already been raised against Question 2 in Massachusetts. It's one of those claims that makes intuitive sense, but research suggests it's simply not true.

That's not just my opinion. A few years ago the White House asked the National Research Council to look at the data being collected about illegal drugs in order to better understand how that data could be used to inform policy. The NRC report, "Informing America's Policy on Illegal Drugs: What We Don't Know Keeps Hurting Us," looked in some detail at what research tells us about the effect of drug laws.

Here's a bit of what they had to say, from pages 192-193 of the report:

The issue most extensively studied has been the impact of decriminalization on the prevalence of marijuana use among youths and adults. Penalties for possession of small amounts of marijuana for personal use were significantly reduced in 11 states in the 1970s (Bonnie, 1981b). All of these laws preclude incarceration for consumption-related marijuana offenses, making the offense punishable only by a fine, and most also classify the offense in a category (typically a civil infraction) that does not carry the stigmatizing consequence of having been convicted of a crime— hence the term 'decriminalization.'

Most cross-state comparisons in the United States (as well as in Australia; see McGeorge and Aitken, 1997) have found no significant differences in the prevalence of marijuana use in decriminalized and nondecriminalized states (e.g., Johnston et al., 1981; Single, 1989; DiNardo and Lemieux, 1992; Thies and Register, 1993). Even in the few studies that find an effect on prevalence, it is a weak one. ...

In summary, existing research seems to indicate that there is little apparent relationship between severity of sanctions prescribed for drug use and prevalence or frequency of use, and that perceived legal risk explains very little in the variance of individual drug use.

The most recent state-level data from the federal National Survey on Drug Use and Health continue to show little difference in use rates between states that have decriminalized marijuana and those that haven't.

For example, in Mississippi, a decrim state, 8.45% of those aged 12 and up say they've used marijuana in the past year. In neighboring Louisiana and Alabama, both of which continue to arrest and jail people caught possessing marijuana, the rates are 9.58% and 7.99%, respectively. Some decrim states, like Oregon, are above the national average of 10.37%, while others are below. Overall, the difference between decrim and non-decrim states is well within the survey's margin of error.

The lesson: Just because something seems like it should be true -- or makes a good sound bite -- doesn't make it so.