More adults using marijuana, poll says

Marijuana use among adults is on the rise in the United States. A new Gallup poll shows the number of pot smokers has nearly doubled in the past three years to one in every 8 Americans.

A 2014 study found that marijuana is the most commonly used illicit drug.

The DEA said smoking pot has been linked to several physical and mental issues.

But marijuana advocates said it is beneficial to those suffering from diseases and medical conditions such as cancer and epilepsy.