Scientists reported today that they have figured out how the popular illicit stimulant Captagon works and that they may have a way to combat its effects.

• Captagon or fenethylline is popular in Saudi Arabia and throughout the Gulf (where counterfeit pills also abound).
• There have been reports of the "Jihadi pill" being used by ISIS fighters as a performance stimulator—though that has been questioned.
• The drug was first used in the 1960s to treat attention deficit hyperactivity disorder and narcolepsy but became illegal in most countries, including the U.S., in the 1980s after its addictiveness became apparent.

How it works: When ingested, fenethylline is broken down to the stimulant amphetamine and theophylline (a caffeine-like substance that relaxes the muscles around the lungs and is used to treat respiratory diseases). It was unclear how exactly the drug works in the body. Kim Janda and his colleagues from Scripps Research Institute found the combination of theophylline and amphetamine greatly enhances amphetamine's psychoactive properties.

"This drug is much more dangerous than was previously thought in terms of its overall psychoactive properties. We need greater awareness of the issues and its abuse effects" Janda said in a press conference.

What they did: The researchers made fenethylline in the lab (producing it is relatively easy and it's believed to be a revenue source for ISIS). They then vaccinated mice against the different components of fenethylline, administered the drug and determined how each substance affected their vigilance and movement, as well as the drug's uptake by the brain and body.

Janda, who is working on a vaccine for heroin, says the initial intent of the study wasn't a vaccine for fenethylline but that the study vaccine's components could be adjusted if there was interest in developing a vaccine for humans.

A term to know: Pharmacoterrorism refers to drugs originally produced for therapeutic benefit being abused in terror attacks for morale building or hypervigilance or to therapeutic drugs being weaponized.

Important side note: The researchers say their vaccine approach could be used to better understand how other drugs affect the brain. "[Natural products, anti-depressants, anti-psychotics, anti-seizure and other complex drugs] typically have multiple targets and figuring out how they interact with those targets is challenging. This approach can be used to figure out what effects are useful and helpful, and which are toxic or potentially link with abuse liabilities," says Janda.