Many marijuana prohibitionists insist one reason to keep marijuana illegal is that it causes mental illnesses, despite many scientific studies that say otherwise. A new study conducted through the Harvard Medical School adds to that body of research and shows that marijuana use is unlikely to be a cause of schizophrenia. The researchers studied four groups: people with no history of psychosis and no history of marijuana use, people with no history of psychosis who were heavy marijuana users as adolescents,…

On July 2, an article by Dr. Samuel T. Wilkinson was published in the Wall Street Journal positing that marijuana use can drastically increase one’s predisposition towards schizophrenia and other mental illnesses. Dr. Wilkinson cites research stating that teenage and early 20s use of marijuana holds a causal link to later development of schizophrenia. However, this data is simply not a credible argument against making marijuana legal. Within his own article, Dr. Wilkinson discusses the “cliff of…

There has long been reason to think that marijuana may be helpful to some patients with bipolar disorder, as certain cannabinoids have been shown in lab and animal studies to have effects that ought to be beneficial. Now, a new study from the University of Oslo finds that marijuana use is associated with better neurocognitive functioning in bipolar patients. In various tests of memory, learning, etc., bipolar patients who used marijuana did better than those who didn’t use it – the exact opposite…

At least some in the international news media have belatedly discovered a study casting doubt on the purported link between marijuana use and schizophrenia. I say “belatedly” because the study was published online back in June, although the print version came out this month. A group of British researchers examined a rather basic notion: If marijuana use  causes schizophrenia, then a major increase in marijuana use should lead to an increase in schizophrenia diagnoses in the following years. In an…

The surprising finding that THC might help at least a small percentage of schizophrenia patients for whom conventional treatments have failed was reported in the June issue of the Journal of Clinical Psychopharmacology.  This is surprising because, as the British government's Advisory Council on the Misuse of Drugs reported last year, "there is clear evidence that the use of cannabis may worsen the symptoms of schizophrenia and lead to relapse." The ACMD -- a far more objective body than any U.S.…