Bipolar disorder and was once known as manic-depression
Mania: great energy and enthusiasm for everything
Bipolar disorder is one of the two major types of mood disorders. The other type is unipolar depression,
in which people experience only depression, without mania.
experience delusions and hallucinations. Delusions are beliefs with no basis in reality, and hallucinations
involve seeing, hearing, or feeling things that are not real.
The DSM-IV-TR recognizes two categories of unipolar depression: major depression and dysthymic
disorder. The diagnosis of major depression requires that a person experience either depressed mood or
loss of interest in usual activities, plus at least four other symptoms of depression chronically for at least
two weeks. In addition, these symptoms have to be severe enough to interfere with the person's ability to
function in everyday life.
Dysthymic disorder is a less severe form of depressive disorder than is major depression, but it is more
chronic. Diagnosed: experiencing depressed mood plus two other symptoms of depression for at least
two years. During these two years, the person must never have been without the symptoms of depression
for more than a two-month period. Some people experience both major depression and dysthymic
disorder. This has been referred to as double depression. People with double depression are chronically
dysthymic, and then occasionally sink into episodes of major depression.
Most people with this have another psychological disorder, usually substance abuse, anxiety or eating
Subtype Characteristics of symptoms
With melancholic features Inability to experience pleasure, distinct depressed
mood, depression regularly worse in morning, early
morning awakening, marked psychomotor
retardation or agitation, significant anorexia or
weight loss, excessive guilt
With psychotic features Presence of depressing delusions or hallucinations
With catatonic features Catatonic behaviors: catalepsy, excessive motor
activity, severe disturbances in speech
With atypical features Positive mood reactions to some events, significant
weight gain or increase in appetite, hypersomnia,
heavy or laden feelings in arms or legs, long-
standing pattern of sensitivity to interpersonal
With postpartum onset Onset of major depressive episode within four
weeks of delivery of child
With seasonal pattern History of at least two years in which major
depressive episodes occur during one season of the
year (usually the winter) and remit when the
season is over
People who experience manic episodes meeting these criteria are said to have bipolar I disorder. Most
of these people eventually fall into a depressive episode. For some people with bipolar I disorder, the
depressions are as severe as major depressive episodes, whereas others have episodes of depression
that are relatively mild and infrequent. People with bipolar II disorder experience severe episodes of depression that meet the criteria for major depression, but their episodes of mania are milder and are
known as Hypomania has the same symptoms as mania. The major difference is that, in hypomania,
these symptoms are not severe enough to interfere with daily functioning and do not involve
hallucinations or delusions.
dysthymic disorder is the less severe but more chronic form of unipolar depression, there is a less severe
but more chronic form of bipolar disorder, known as cyclothymic disorder. A person with cyclothymic
disorder alternates between episodes of hypomania and moderate depression chronically over at least a
two-year period. During the hypomania, the person may be able to function reasonably well in daily life
If a person has four or more cycles of mania and depression within a year, this is known as rapid cycling
o Disordered genes predispose people to depression or bipolar disorder.
o Dysregulation of neurotransmitters and their receptors causes depression and mania.
The monoamine neurotransmitters—norepinephrine, serotonin, and dopamine—have
been most researched.
o Abnormalities occur in the structure and functioning of the prefrontal cortex,
hippocampus, anterior cingulate cortex, and amygdala.
o Depressed people show chronic hyperactivity in the hypothalamic-pituitary-adrenal axis
and slow return to baseline after a stressor, which affects the functioning of
The onset of bipolar disorder is most often in late adolescence or early adulthood. Most people
with bipolar disorder have multiple episodes.
Biochemical theories of mood disorders have focused on neurotransmitters, , but the neurotransmitters
that have been implicated most often are the monoamines.
The specific monoamines that have been implicated are norepinephrine, serotonin, and, to a lesser
extent, dopamine. These neurotransmitters are found in large concentrations in the limbic system, a
part of the brain associated with the regulation of sleep, appetite, and emotional processes. These
neurotransmitters are thought to cause both depression and mania—imbalances in one direction may
cause depression and imbalances in the other direction may cause mania.
The early theory of the roles of these neurotransmitters in mood disorders was that depression was
caused by a reduction in the amount of norepinephrine or serotonin in the synapses between. This
depletion could occur for numerous reasons: decreased synthesis of the neurotransmitter from its
precursors, increased degradation of the neurotransmitter by enzymes, or impaired release or reuptake
of the neurotransmitter. This was thought to be caused by an excess of the monoamines or perhaps
dysregulation of the levels of these amines, especially dopamine. Taken together, these theories are
known as the monoamine theories of mood disorders
Neuroimaging studies done by using computerized tomography (CT) scans, positron-emission
tomography (PET), and magnetic resonance imaging (MRI) have found consistent abnormalities in at
least four areas of the brain in people with mood disorders: the prefrontal cortex, the hippocampus, the
anterior cingulate cortex, and the amygdala
The anterior cingulate plays an important role in the body's response to stress, in emotional expression,
and in social behaviour, as well as in the processing of difficult information