I know at least 20 professionals that use it recreationally on a regular basis, all are productive members of society. I know at least 5 people with elderly loved ones who wish they could get them some relief from various conditions using marijuana.
Of course the next battle will be the psychadelics: LSD, shrooms, MDMA (ecstacy), DMT and Ayahuasca. There are studies going on researching their effectiveness at treating PTSD among other things. There are also several documentaries out there about their effectiveness at treating Anxiety and Depression. Also, that loon Sam Harris that I listen to is a strong proponent, not sure if that's a great endorsement or not...