Insomnia is not a sleep disorder in and of itself, but a related symptom of other problems, including an assortment of common physical and psychological disruptions in the sleep cycle. Symptoms of insomnia can be brought on by physical situations, such as medical conditions, hormonal changes, changes in diet, changes in work schedule, exercise or lack of; environmental situations including changes in time zone, changes in season, travel and cultural changes, and more; and psychological problems including stress, depression, and anxiety.