A dangerous new substance that may cause brain damage has been found mixed with cocaine by Swiss researchers.

After marijuana, cocaine is the second-most consumed illegal drug around the world. Unlike weed, however, it's usually ingested in an impure "cut" form, with drug dealers adding substances to the coke in order to increase their profitability. These often-hazardous additives can be laundry detergents, baking soda, ammonia, as well as local anesthetic agents, painkillers and caffeine, which mimic some of the effects of cocaine at a lower cost.

Now, two studies from the University of Zurich (UZH) show that levamisole, an animal anti-worming agent, has been turning up in the cocaine supply. Levamisole can impart cognitive performance and thin out the prefrontal cortex in regular cocaine users. The reason levamisole may be added to cocaine is to prolong the drug's effects.

The side effects of this substance can be brutal - leading to changes in blood counts and blood vessels. Previous animal testing revealed levamisole can attack the nervous system. The new Swiss studies show just how much.

By analyzing the hair of cocaine users who participated in their first study, the team from the Psychiatric Hospital and the Institute of Forensic Medicine of the University of Zurich showed that those who took cocaine laced with more levamisole exhibited even worse impairment of cognitive functions.

A second MRI-based study revealed that people who took cocaine with a high level of levamisole showed a very clear thinning of the prefrontal cortex – the part of the brain responsible for executive functions.

The research team's leader UZH Professor Boris Quednow was unequivocal in highlighting levamisole's toxic effects on the brains of cocaine users. He also called for governments to expand drug-checking programs that would allow users to check cocaine for purity.

"We can assume from our findings that it is not just cocaine that changes the brain, but that the adulterant levamisole has an additional harmful effect, " said Quednow. "The sorts of cognitive impairment often exhibited by cocaine users may therefore be exacerbated by levamisole."

You can read the new study in Nature's Translational Psychiatry.

If you need help with cocaine abuse, please don't hesitate to call 1-800-662-HELP (4357) - that's the National Helpline set up by the Substance Abuse and Mental Health Services Administration. It's staffed 24/7, 365 days a year.