After thorough obedience training, service dog training teaches your dog the tasks to perform to mitigate your disability (see this sample list of tasks your dog could learn).
I will be creating a page here for sample tasks for psychiatric disabilities, so tune back in soon, and many YouTube videos provide instruction.
Basic service tasks can be taught easily--many can be taught even more easily than basic obedience and public behavior! However, complex work (e.g., guide dogs for visually impaired individuals) can require much more training.
See also: "FAQ: Training--Beyond Basics,"
Psychiatric Service Dog Partners.