The diagnostic criteria for depressive disorders given by the 10th edition of the International Classification of Diseases include (three core symptoms) depressed mood, loss of interest and pleasure, decreased energy leading to increased exertion and decreased activity, other symptoms include decreased ability to focus and pay attention, decreased self-esteem and self-confidence, self-guilt and feelings of worthlessness, perceptions of a bleak and pessimistic future, self-injurious or suicidal thoughts or behaviors, sleep disturbances, and decreased appetite. Some symptoms of chronic pain or autonomic dysfunction may also be present.