A mood disorder, also known as an affective disorder, is any of a group of conditions of mental and behavioral disorder where a disturbance in the persons mood is the main underlying feature. The classification is in the Diagnostic and Statistical Manual of Mental Disorders (DSM) and International Classification of Diseases (ICD). Mood disorders fall into seven groups, including; abnormally elevated mood, such as mania or hypomania; depressed mood, of which the best-known and most researched is major depressive disorder (MDD) (alternatively known as clinical depression, unipolar depression, or major depression); and moods which cycle between mania and depression, known as bipolar disorder (BD) (formerly known as manic depression). There are several sub-types of depressive disorders or psychiatric syndromes featuring less severe symptoms such as dysthymic disorder (similar to MDD, but longer lasting and more persistent, though often milder) and cyclothymic disorder (similar to but milder than BD).In some cases, more than one mood disorder can be present in an individual, like bipolar disorder and depressive disorder. If a mood disorder and schizophrenia are both present in an individual, this is known as schizoaffective disorder. Mood disorders may also be substance induced, or occur in response to a medical condition. English psychiatrist Henry Maudsley proposed an overarching category of affective disorder. The term was then replaced by mood disorder, as the latter term refers to the underlying or longitudinal emotional state, whereas the former refers to the external expression observed by others.
Due to another medical condition
"Mood disorder due to a general medical condition" is used to describe manic or depressive episodes which occur secondary to a medical condition. There are many medical conditions that can trigger mood episodes, including neurological disorders (e.g. dementias), metabolic disorders (e.g. electrolyte disturbances), gastrointestinal diseases (e.g. cirrhosis), endocrine disease (e.g. thyroid abnormalities), cardiovascular disease (e.g. heart attack), pulmonary disease (e.g. chronic obstructive pulmonary disease), cancer, and autoimmune diseases (e.g. multiple sclerosis). Not otherwise specified
Mood disorder not otherwise specified (MD-NOS) is a mood disorder that is impairing but does not fit in with any of the other officially specified diagnoses. In the DSM-IV MD-NOS is described as "any mood disorder that does not meet the criteria for a specific disorder." MD-NOS is not used as a clinical description but as a statistical concept for filing purposes. The diagnosis of MD-NOS does not exist in the DSM-5, however the diagnoses of unspecified depressive disorder and unspecified bipolar disorder are in the DSM-5.Most cases of MD-NOS represent hybrids between mood and anxiety disorders, such as mixed anxiety-depressive disorder or atypical depression. An example of an instance of MD-NOS is being in minor depression frequently during various intervals, such as once every month or once in three days. There is a risk for MD-NOS not to get noticed, and for that reason not to get treated. Causes
Meta-analyses show that high scores on the personality domain neuroticism are a strong predictor for the development of mood disorders.