Recent years have seen the increased use of club drugs known as “bath salts” — synthetic versions of cathinone, an amphetamine-like stimulant found in the East African khat plant (Catha edulis).

The problem is that these drugs are relatively new, so little is known about their effect on the body or how they interact with other drugs, according to Richard Green, a research scientist at the University of Nottingham in the U.K.

Mephedrone is more likely than MDMA to cause dependence and leave users with severe withdrawal symptoms.

Mephedrone is one of these new drugs. It has some effects similar to those of MDMA or ecstasy: both compounds raise levels of the neurotransmitters dopamine and serotonin in the brain, so they have similar effects, Green told TheDoctor. Both compounds cause hallucinations and have an energizing effect, making them popular club drugs.

Green is an author of a new study suggesting that mephedrone is not as harmless as it might seem. His team compared the effects of mephedrone in lab rodents to those of MDMA — methylenedioxymethamphetamine.

The researchers found that mephedrone is more likely than MDMA to cause dependence and leave users with severe withdrawal symptoms.

Mephedrone gets into the brain rapidly, so it takes effect quickly before it’s broken down and cleared. It has a short half-life. This spike may lead to severe withdrawal symptoms that do not occur with MDMA, which has slower brain penetration, metabolism, and clearance.

Even though mephedrone and MDMA both affect dopamine and serotonin in the brain, the balance between the release of these two neurotransmitters is different. Its short half life seems to make mephedrone more reinforcing and according to Green may explain why some users reportedly take repeat doses in rapid succession.

Fortunately, most young people stop using MDMA and mephedrone as they move away from the club scene, but the action of mephedrone is such that the risk of addiction may be greater.

The study is published in the British Journal of Pharmacology.