1. Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
2. Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada.
3. St. Mary's Hospital, Montreal, Quebec, Canada.
4. Department of Psychiatry, McGill University, Montreal, Quebec, Canada.
5. North York General Hospital, Toronto, Ontario, Canada.
6. Department of Psychiatry, University of Calgary, Calgary, Alberta, Canada.