Is marijuana a gateway drug?

The gateway theory seems reasonable enough at first
25 March 2015
Other news

In the past few years, the number of monthly marijuana users in America has steadily risen, from 14.4m in 2007 to 18.9m in 2012.

Published at
The Economist

If marijuana were a gateway to harder drugs, one might expect those drugs to become more popular too. Yet during the same period, consumption of most other substances actually fell. The number of monthly cocaine users dipped from 2.1m to 1.7m and the number of people using methamphetamine fell from 530,000 to 440,000. Heroin use has been going up, but the gateway drug there seems to be prescription painkillers.

The Economist (UK)
Thursday, March 26, 2015