Mood disorders (also called affective disorders) are a group of mental disorders whereby the prevailing emotional mood of a person is distorted or inappropriate to the circumstances. People who suffer from a mood disorder may suffer from constant or interspersed intensified moods. A person's mood generally means their emotional state or the general tone of their feelings. Examples of commonly experienced moods include: sadness, happiness, anger, irritability, depression, mania, hypomania, euphoria, dysphoria or elation. Mood disorders are commonly understood in terms of different types of mood episodes that are experienced.