It's long been held that marijuana use in its traditional form can lead to positive patient experiences, but confirming those personal testimonials in large, placebo-controlled studies has been tough to do.

The difficulty in proving that marijuana can successfully treat disease was hammered home last week when GW Pharmaceuticals (NASDAQ:GWPH) reported results from a schizophrenia trial that raises as many questions as it answers.

Treating the tough-to-treat
Because people suffering from schizophrenia suffer from difficulties in thinking, perceiving the world around them, and controlling their emotional responses, schizophrenia is notoriously difficult to treat.

Currently, treatment comprises of therapy and antipsychotics, such as the megablockbuster Abilify, that bind to neurotransmitters in order to influence the production of dopamine and serotonin, which are associated with a variety of mental disorders.

However, treatment with medication is far from perfect. Because patients taking these drugs have to deal with a range of...