Just read impressive research by National Academy of Science titled: The Health Effects of Cannabis and Cannabinoids.

Did an impressive job on the thourough research with clear chapter highlights and findings.

The book is available free for download.  Here is the studies webpage

http://nationalacademies.org/hmd/reports/2017/health-effects-of-cannabis-and-cannabinoids.aspx

 

Here is a segment of the chapter highlight

http://nationalacademies.org/hmd/~/media/Files/Report%20Files/2017/Cannabis-Health-Effects/Cannabis-chapter-highlights.pdf

 

MENTAL HEALTH
Cannabis use is likely to increase the risk of developing
schizophrenia and other psychoses; the higher the use
the greater the risk.
In individuals with schizophrenia and other psychoses,
a history of cannabis use may be linked to better
performance on learning and memory tasks.
Cannabis use does not appear to increase the likelihood
of developing depression, anxiety, and posttraumatic
stress disorder.
For individuals diagnosed with bipolar disorders, near
daily cannabis use may be linked to greater symptoms
of bipolar disorder than non-users.
Heavy cannabis users are more likely to report thoughts
of suicide than non-users.
Regular cannabis use is likely to increase the risk for
developing social anxiety disorder.