The present report introduces the definition of occupational therapy by the Physical Therapists and Occupational Therapists Act and the recently revised definition by the Japanese Association of Occupational Therapists. The history of occupational therapy in psychiatry starting from moral treatment is also introduced, describing the opposing movements against the introduction of the medical fee reimbursement system to occupational therapy, which have significantly influenced its advancement.
 Therapeutic procedures or methods were classified into five groups, and the period for the implementation of occupational therapy was classified into the following stages: acute, subacute,(first and second)convalescent, and chronic. This report presents the objectives and roles of occupational therapy according to the patient conditions in each stage. Ideal interprofessional collaboration was also discussed to help occupational therapists implement the procedures effectively and efficiently. Finally, the roles of occupational therapy for providing discharge support are described using specific case examples.
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