A study done on rats has found that  bath salts, made with synthetic chemicals, may be more addictive than meth or methamphetamine.

Addiction to meth is believed to be the most difficult forms of addictions to treat. It is the world's most dangerous drug as it provides both the hyperactive effect of cocaine and delusional effect of LSD. But in a new study conducted on rats, researchers found that rats worked 10 times harder to get an additional dosage of methylenedioxypyrovalerone (MDPV) than they did to get meth. The findings suggest that MDPV is a greater threat and more addictive than meth.

"MDPV is more effective than methamphetamine - it's rewarding, and more pleasurable to the animal," said study researcher Michael Taffe, a psychologist at the Scripps Research Institute, reports LiveScience. The study was conducted on rats, which feature similar addictive response like humans and "the drugs that are readily self-administered by rats tend to be the compounds that have abuse liability in humans," Taffe added.

MDPV is a psychoactive drug with fine crystalline powder similar to powdered sugar. It is a compound found in bath salts that is derived from cathinone, an active ingredient in kath plant.  After taking MDPV, the rats repeatedly licked, bit and sniffed, behavior seen in people who are high on drugs.  

For the study, researchers from the Scripps Research Institute designed an operant chamber with clear plastic walls and a lever that delivered either MDPV or meth when pressed. Some rats were given meth and some received MDPV. Researchers trained rats on using the lever for more doses. Rats were sometimes rewarded with additional doses by pressing the lever several times. This helped researchers to find how much they craved to get an additional dose of either drug.

"When we increased how many lever presses a rat would have to emit to get an additional infusion of drug, we observed that rats emitted about 60 presses on average for a dose of METH but up to about 600 for MDPV-some rats would even emit 3,000 lever presses for a single hit of MDPV," said study author Shawn M. Aarde, according to Forbes. "If you consider these lever presses a measure of how much a rat will work to get a drug infusion, then these rats worked more than 10 times harder to get MDPV."

The rats' repetitive behavior resembled that of humans' addiction to bath salts. In this case, rats licked the plastic walls of the chamber repeatedly, which could be compared with human behavior of tooth-grinding and skin-picking when high on meth or bath salts, according to the researchers.

 The findings of the study are published in the journal Neuropharmacology.