1. A method comprising: determining, at a computing device, sleep cycle information associated with a sleep cycle of a patient based on body parameter data; adjusting, at the computing device, a cranial nerve stimulation parameter based on the sleep cycle information, wherein the sleep cycle information includes an amount of time the patient has spent in a particular sleep stage; and treating depression in the patient by initiating application of a cranial nerve stimulation therapy to the patient based on the adjusted cranial nerve stimulation parameter.