Mood Disorders

Type of psychology: Psychopathology
Field of study: Depression
The diagnosis of a mood disorder requires the presence or absence of a mood episode
such as a major depressive episode, manic episode, mixed episode, or hypomanic episode.
Mood disorders include major depressive disorder, dysthymic disorder, bipolar I
disorder, bipolar II disorder, and cyclothymic disorder. The mood disorders can be specified
with seasonal pattern, rapid-cycling, or postpartum onset.

Key concepts
• bipolar I disorder
• cyclothymic disorder
• depressive episode
• dysthymic disorder
• hypomanic episode
• major depressive disorder
• manic episode
• postpartum onset
• rapid-cycling
• seasonal pattern
Descriptions of mood disorders can be found in ancient texts such as the Bible
and the writings of Hippocrates (c. 460-c. 377 b.c.e.). In about 30 c.e.,
Aulus Cornelius Celsus, a medical writer, described melancholia as a depression
caused by black bile.

Mood disorders are characterized predominantly by a disturbance in
mood. The American Psychiatric Association’s Diagnostic and Statistical Manual
of Mental Disorders: DSM-IV-TR (rev. 4th ed., 2000) describes mood episodes
that characterize the mood disorders: major depressive episode, manic
episode, mixed episode, and hypomanic episode.
In a major depressive episode, a person experiences depressed mood for
a period of at least two weeks. For the diagnosis of a depressive episode, the
person must experience at least four of the following symptoms: changes in
appetite or weight, sleep, and psychomotor activity; decreased energy; feelings
of worthlessness or guilt; difficulty concentrating; recurrent thoughts
of death or suicide. There is significant impairment in occupational or social
functioning.

In a manic episode, a person experiences an abnormally elevated or irritable
mood for at least one week. In addition, the person must experience at
least three of the following symptoms: inflated self-esteem, decreased need
for sleep, pressured (loud, rapid) speech, racing thoughts, excessive planning
of or participation in multiple activities, distractibility, psychomotor
agitation (such as pacing), or excessive participation in activities that may
have negative consequences (such as overspending). There is severe impairment in social or occupational functioning, or there are psychotic features.
A hypomanic episode is characterized by a period of at least four days of
abnormally elevated or irritable mood. The affected person must experience
at least three of the following symptoms: inflated self-esteem, decreased
need for sleep, pressured speech, flight of ideas, increased involvement in
goal-directed activities, psychomotor agitation, or excessive participation in
activities that may lead to negative consequences. The hypomanic episode is
differentiated from the manic episode by less severe impairment in social or
occupational functioning and a lack of psychotic features.

A person experiencing a mixed episode displays symptoms of both manic
and major depressive episodes nearly every day for a period of one week.
Major depressive disorder is characterized by one or more major depressive
episodes. Dysthymic disorder involves at least two years of depressed
mood with symptoms that do not meet the criteria for a major depressive episode.
Bipolar I disorder includes one or more manic or mixed episodes
with major depressive episodes. Bipolar II disorder is characterized by one
or more major depressive episodes with at least one hypomanic episode.
Cyclothymic disorder is represented by at least two years of hypomanic episodes
and depressive symptoms that do not meet the criteria for a major depressive
episode.