The Israel scientist Raphael Mechoulam has been researching what’s thought to be the world’s most popular drug since the 1960s. In 1964, he isolated Tetrahydrocannabinol, or THC – the compound that gets cannabis-users high. Later, professor Mechoulam discovered another compound called CBD, or Cannabidiol, which has medical benefits without any kind of psychoactive effect. Recently, CBD has had a revolutionary impact on treating health conditions such as epilepsy. Prof Mechoulam talks to Claire Bowes.

(Photo: A marihuana plant in India. Credit: Getty Images)