1. A method comprising: monitoring at least one physiological parameter of a patient via a medical device that delivers at least one of a movement disorder therapy, psychological disorder therapy, or deep brain stimulation to a patient; determining a value of a metric that is indicative of sleep quality based on the at least one physiological parameter; and controlling delivery of the least one of the movement disorder therapy, psychological disorder therapy, or deep brain stimulation by the medical device based on the sleep quality metric value.