Bipolar disorder is a recurrent psychiatric illness characterized by recurring episodes of mania and depression. Individuals diagnosed with bipolar disorder display extreme shifts in mood, energy level, thinking, and activities of daily living. Patients require lifelong treatment to control symptoms. The cause of bipolar disorder is unknown; however, evidence exists that indicates a chemical imbalance with neurotransmitters is involved. Excess norepinephrine and dopamine may be present in mania, whereas a deficiency of serotonin, norepinephrine, and dopamine may be present in depression. Medications used to manage the symptoms of bipolar disorder alter the transmission of serotonin, dopamine, norepinephrine, as well as gamma-aminobutyric acid (GABA), glutamate, and aspartate. Additionally, family studies provide evidence for a genetic association of developing bipolar disorder.
Clinical Presentation and Diagnosis
Discrete types of mood episodes are classified as manic, hypomanic, depressive, or mixed type. Mania is the hallmark of bipolar disorder. The signs and symptoms of mania include an elated, euphoric, expansive, or irritable mood; increased self-esteem or grandiosity; a decreased need for sleep; talkative or pressured speech; racing thoughts or flight of ideas; distractibility; increased goal-directed activities; and psychomotor agitation. The patient may also report an increase in risk-taking behaviors or excessive involvement in pleasurable activities (eg, sexual promiscuity, unrestrained buying sprees). Three or more of these symptoms must be present in a patient if his/her mood is euphoric or expansive; four or more if the mood is irritable. These symptoms must last at least 1 week or any duration if hospitalization was required. Psychosis may accompany a manic episode. Hypomania is a less severe form of mania, lasting at least 4 consecutive days and not requiring hospitalization. Patients state that they are more creative, feel more important, become extremely productive, and that they do not need medical treatment. If a depressive episode alternates with the manic episodes, the patient is classified as having bipolar depression (as opposed to unipolar depression, otherwise known as major depressive disorder). An example of the episodic course of bipolar disorder includes one manic episode followed by three depressive episodes over several years, with or without a return to mania. Another example may include an initial depressive episode lasting a few months followed by a manic episode, then a return to a depressive episode several months to years later. Mixed (or dysphoric) type includes episodes of both mania and major depression occurring at the same time for at least 1 week. Agitation, psychosis, and suicidality are symptoms associated with mixed episodes. Rapid cycling is a term to describe when a patient experiences four or more episodes of depression or mania within a 12-month period.
There are different types of bipolar disorder diagnoses. Bipolar I disorder includes manic or mixed episodes usually accompanied by major depressive episodes. Bipolar II includes major depressive episodes in addition to hypomanic episodes. Cyclothymic disorder involves recurring hypomania with additional depressive symptoms that recur for a ...