Dame Ruth Runciman, the UKDPC chairwoman, said while Government programmes to reduce the damage caused by drug problems - like needle exchanges and investment in treatment for addicts - are supported by evidence, "much of the rest of drug policy does not have an adequate evidence base."
We spend billions of pounds every year without being sure of what difference much of it makes.
A fellow commission member, the former chief executive of the Medical Research Council Professor Colin Blakemore, added:
Medicine has moved past the age when we treated disease on the basis of hunches and received wisdom. The overwhelming consensus now is that it is unethical, inefficient and dangerous to use untested and unvalidated methods of treatment and prevention. It is time that policy on illicit drug use starts taking evidence seriously as well.
More top news
Records reveal The Lord of the Rings and The Hobbit might never have been written had JRR Tolkien not fallen ill with “trench fever”
Astronauts living on Nasa's Space Station no longer need to worry if they forget to pack something - they can just 3D print what they need.
Scientists have discovered the world's deepest fish with wing-like fins and an eel-like tail during research in the depths of the Pacific.