We, Washington state voters, will be asked on Nov. 6 to consider Initiative 502 on legalizing marijuana.
Marijuana use is proven to lower IQ on average by eight points. Here is one such study report: http://www.webmd.com/brain/news/20120827/pot-use-teen-years-lower-iq?.
It impairs a wide range of cognitive performance skills, and it does so permanently. The impairment persists even if marijuana use is stopped. Here is one such study report: http://www.pnas.org/content/early/2012/08/22/1206820109.abstract.
Marijuana makes schizophrenia and other psychiatric illnesses worse, and two-thirds of patients with schizophrenia use marijuana, as reported here: http://ajp.psychiatryonline.org/article.aspx?Volume=167&page=987&journalID=13.
Marijuana also causes permanent psychosis, as this scientific study measured: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3047001/?tool=pubmed.
Marijuana has valuable medical benefits for people with glaucoma or cancer pain and should be made available to them on a humanitarian basis. Otherwise, it is a toxic substance, and its use should be strongly discouraged.