There has been evidence of this association floating around for ages. On the balance of evidence there may be reason for concern, but in particular as with anything in medicine, the right decision for any individual may come from presence of the right (or wrong) risk factors.
See e.g. : http://www.sciencedaily.com/releases/2012/11/121114083928.htm http://www.forbes.com/sites/alicegwalton/2012/01/11/the-neuroscience-of-pot-researchers-explain-why-marijuana-may-bring-serenity-or-psychosis/
One factor that would seem to be relevant is the proportion of THC and cannabidiol (http://en.wikipedia.org/wiki/Cannabidiol) present in plant strains, and change in ratios from decades past as plant breeding has changed the landscape of what effects may be expected from a particular plant.
The extreme reaction of "Reefer Madness" is almost certainly misguided, but there is reason to suggest that more science is needed towards ascertaining that the full benefits may be had, and risk factors removed (e.g. via genetic tests and controlled breeding/testing of plant strains) whether for medicinal purposes or otherwise.