The mood disorders: Depression and Bipolar Affective Disorder

Changes in mood are a normal part of life. Sadness, elation, anger or lack of enjoyment can occur in response to life events, such as moving home, starting or ending a relationship, the death of a friend, or many other events. However, mood symptoms which are severe, distressing or prolonged could represent a mood disorder which may be understood as an illness which mainly affects the mood. There need not be a specific trigger to an episode of mood disorder. Mood disorders are also referred to as Affective Disorders and there are a number of different mood disorders. People who experience mood disorders may present with a variety of symptoms and signs which can be sustained over periods of weeks and months. These are associated with a marked change in their day to day function. People may experience a single episode of mood disorder or the symptoms can recur in a periodic or cyclical pattern. People with intellectual disability are at increased risk of mood disorders, with estimated prevalence rates of 4% for depression and 1.5% for bipolar affective disorder. In the following sections, depression, bipolar affective disorder and adjustment disorders will be reviewed.