The synthetic molecule is fenethylline, used as a stimulant  and marketed under the brand name Captagon  to treat hyperactivity, narcolepsy and depression. It was produced by Degussa AG in 1961 but was banned in most countries by the 1980s as too addictive. It remains hugely popular in the Middle East and especially in Lebanon and Syria.

The drug is cheap and simple to produce, using ingredients that are easy and often legal to obtain, yet sells for up to $20 a tablet. It is said  said that Captagon had “the typical effects of a stimulant”, producing “a kind of euphoria. You’re talkative, you don’t sleep, you don’t eat, you’re energetic.”

Those effects explain why fighters from most of the warring parties in the conflict are now said to be making extensive use of Captagon, often on night missions or during particularly gruelling battles. But doctors and psychiatrists say use of the drug is also becoming widespread among  civilian population.

With porous borders and little oversight in many areas of the country, Syria and Lebanon are a lucrative production hub for brewers and smugglers of the illegal amphetamine. Lebanon, specifically the Bekaa Valley, has traditionally been a large producer and exporter of Captagon, but the war in Syria seems to be attracting Syrians and Lebanese drug-makers alike to its chaotic cities.