Prescription painkillers are being used as recreational drugs.
The popularity of MDMA (Ecstasy) as a recreational drug exploded among young people.
He is concerned that the use of recreational drugs by athletes has grown since he has been away from football.
Each of the volunteers is required to keep a daily log not only of their marijuana use, but also alcohol and other recreational drugs.
He admits to recreational drug use, both marijuana and cocaine, as a teenager.
