BC Mental Health and Substance Use Services provides specialized treatment for clients with complex concurrent disorders in B.C. Clients are referred to the service by regional health authorities when they require more specialized treatment than that which is available in the community. BC Mental Health and Substance Use Services does not offer psychiatrist referrals or walk-in appointments. The organization also provides provincial leadership for system-wide improvement through health promotion and illness prevention; knowledge exchange; and research and academic teaching. Part of the Provincial Health Services Authority (PHSA).