Links
[1] http://m.pnas.org/content/111/47/16913.full.pdf
[2] http://www.rethinkpot.org/tags/long-term
[3] http://www.rethinkpot.org/tags/side-effects
[4] http://www.rethinkpot.org/tags/brain
[5] http://www.rethinkpot.org/tags/research
[6] http://www.rethinkpot.org/tags/study