Nora D. Volkow, MD; James M. Swanson, PhD; A. Eden Evins, MD; Lynn E. DeLisi, MD; Madeline H. Meier, PhD;
Raul Gonzalez, PhD; Michael A. P. Bloomfield, MRCPsych; H. Valerie Curran, PhD; Ruben Baler, PhD
With a political debate about the potential risks and benefits of cannabis use as a backdrop,
the wave of legalization and liberalization initiatives continues to spread. Four states
(Colorado, Washington, Oregon, and Alaska) and the District of Columbia have passed laws
that legalized cannabis for recreational use by adults, and 23 others plus the District of
Columbia now regulate cannabis use for medical purposes. These policy changes could
trigger a broad range of unintended consequences, with profound and lasting implications for
the health and social systems in our country. Cannabis use is emerging as one among many
interacting factors that can affect brain development and mental function. To inform the
political discourse with scientific evidence, the literature was reviewed to identify what is
known and not known about the effects of cannabis use on human behavior, including
cognition, motivation, and psychosis.
. doi: 10.1001/jamapsychiatry.2015.3278
Published online February 3, 2016.