Marijuana use is associated with an increased risk of prescription opioid use.
Marijuana use seems to strengthen the relationship between pain and depression and anxiety, not ease it.
Links
[1] https://docs.google.com/document/d/1EJEuAY9GHE8CZBIvv6Tby98WKBCFl9iJ4DyYOUOMx6I/edit?usp=sharing
[2] http://rethinkpot.org/tags/drug-free-america
[3] http://rethinkpot.org/tags/opioid