With the best of intentions, Missouri lawmakers are poised to pass yet another law to restrict the sale of pseudoephedrine, the active ingredient in most cough and cold medicines and the key ingredient in illegal methamphetamine.

The proposed law would mandate electronic records documenting medication sales. Lawmakers voted two years ago to move over-the-counter cold medicine behind pharmacy counters.

Pseudoephedrine is a precursor needed to make meth. Missouri had, and still has, the largest number of meth lab seizures in the country. Moving pseudoephedrine behind pharmacy counters cut the number of lab seizures in half. Since meth production involves creation of toxic substances that often are improperly disposed of, that’s a good thing.

But the relationship between drug lab seizures, meth production and drug use is far more complicated than generally portrayed. More labs does not necessarily mean more production, and fewer labs does not equate to less use.

Missouri might lead the nation in lab seizures, but it never has been close to the top in meth production. The California desert traditionally has been home to “superlabs,” often elaborately hidden and fortified. Instead of the few ounces that mom-and-pop labs make in places such as Jefferson County, superlabs produce tons of the drug, which is distributed widely.

In recent years, as U.S. authorities cracked down on the sale of precursors, more and larger labs have sprung up in Mexico. The methamphetamine they make generally is purer; product that is more concentrated is easier to conceal and smuggle.

It is tempting to think we can solve the meth problem by restricting access to cold medicine and shutting down labs. That is not how the law of supply and demand works, as increased seizures of Mexican meth clearly show. Cocaine and heroin labs are unheard of in Missouri and most of the rest of the country. But the drugs they produce are available widely.

There is good news and bad news about meth and amphetamine use. A continuing federal study called “Monitoring the Future” — the only long-term national study of drug use by high school students — reported that meth use has peaked and is falling.
In 1998, about 8 percent of high school seniors said they had tried meth. That number has fallen every year since, to just 3 percent in 2007.

But nearly twice that percentage of seniors had abused the amphetamine Ritalin, prescribed to control attention deficit hyperactivity disorder, the 2007 survey found.
High school seniors were more than four times as likely to abuse prescription amphetamines than they were to use meth. The overall rate of prescription drug abuse among teens — including stimulants, sedatives and pain medicine — is considerably higher than methamphetamine use ever was.

The number of students who said they used meth, 1.7 percent, is less than the number who smoked crack, 1.9 percent, and only slightly higher than the 1.4 percent who said they used steroids.

It’s understandable, even honorable, that lawmakers would want to prevent the damage that illegal drugs such as meth can wreak on people’s lives. The question is how best to do that with our limited resources.

Treatment programs for methamphetamine and other drugs, including alcohol, are underfunded in Missouri. Treatment provides a bigger return on investment than enforcement alone.