Matthew Perrone

WASHINGTON: People are inventing so many new ways to get high that lawmakers can’t seem to keep up.

Over the past two years, the United States has seen a surge in the use of synthetic drugs made of legal chemicals that mimic the dangerous effects of cocaine, amphetamines and other illegal stimulants.

The drugs are often sold at small, independent stores in misleading packaging that suggests common household items like bath salts, incense and plant food. But the substances inside are powerful, mind-altering drugs that have been linked to bizarre and violent behavior across the country. Law enforcement officials refer to the drugs collectively as “bath salts,” though they have nothing in common with the fragrant toiletries.

President Barack Obama signed a bill into law earlier this month that bans the sale, production and possession of more than two dozen of the most common bath salt drugs. But health professionals say lawmakers cannot keep pace with bath salt producers, who constantly adjust their chemical formulations to come up with new synthetic drugs that aren’t covered by new laws. Experts who have studied the problem estimate there are more than 100 different bath salt chemicals in circulation.

“The moment you start to regulate one of them, they’ll come out with a variant that sometimes is even more potent,” said Dr. Nora Volkow, director of the National Institute on Drug Abuse.

There are no back alleys or crack houses in America’s latest drug epidemic. The problem involves potent substances that amateur chemists make, package and sell in stores for as little as $15. Emergencies related to the drugs have surged: The American Association of Poison Control Centers received more than 6,100 calls about bath salt drugs in 2011 — up from just 304 the year before — and more than 1,700 calls in the first half of 2012.

The problem for lawmakers is that it’s difficult to crack down on the drugs. U.S. laws prohibit the sale or possession of all substances that mimic illegal drugs, but only if federal prosecutors can show that they are intended for human use. People who make bath salts and similar drugs work around this by printing “not for human consumption” on the packets.