Bipolar disorder Health Article

Definition

Bipolar disorder is characterized by mood swings, which are unpredictable and range from mania (elevated and irritable mood) to depression (a mood characterized by loss of interest and sadness). The disorder causes significant difficulties or impairment in social, occupational, and general functioning capabilities.

Description

Bipolar Type II (BT II) disorder is a psychological disorder characterized by fluctuation of cycles (time periods) of mania and depression. The manic cycle or phase is commonly associated with irritability, decreased need for sleep (sleep disruption), euphoria (an exaggerated false self-perception of feeling good), social extroversion (excessive friendliness), and feeling more important than one truly is (grandiosity). The depressive episode or cycle is correlated with a broad spectrum of symptoms. Most patients in depressive cycles exhibit common symptoms, which include fatigue, impaired concentration/decision making, and altered sleep and appetite patterns. This cycle can further progress to the level where patients feel excessively shameful and guilty. In totality, the symptoms for the depressive cycle can lead to thoughts of death or dying. The disorder is also called Manic-Depressive Psychosis, and Major Affective Disorder.

Genetic profile

There is significant evidence that correlates BT II with genetic causes. Studies have shown monozygotic twins (identical twins) have an 80% concordance rate (presence of the same disorder in twins). Additionally, studies have demonstrated that the disorder is transmitted to children (progeny) by autosomal dominant inheritance. This means that either affected parent has a 50% chance of having a child (regardless if the child is male or female) with the disorder.

Further studies concerning the genetic correlations have revealed specific chromosomes (the structure that contains genes) that contain mutated genes. Susceptible genes are located in specific regions of chromosomes 13, 18, and 21. The building blocks of genes, called nucleotides, are normally arranged in a specific order and quantity. If these nucleotides are repeated in a redundant fashion a genetic abnormality usually results. Recent evidence suggests a special type of nucleotide sequence (CAG/CTG repeats) is observed in patients with BT II on chromosome 18. However, the presence of this sequence does not worsen the disorder or change the age of onset. It is currently thought that expression of BT II involves multiple mutated genes. Further research is ongoing to determine precise mechanisms and to develop genetic markers (gene tags) for predicting which individuals are at higher risk.

Demographics

Manic-depression is a common psychological disorder that is difficult to diagnose (detect). It is estimated that about three million people in the United States are affected. Community oriented studies suggest that the lifetime prevalence (number of cases in terms of time) is approximately 0.5%. The disorder is more common in women than in men. Women have been observed at increased risk of developing subsequent episodes in the immediate period after giving birth. After treatment, most patients with BT II return to fully functional levels. Approximately 15% of patients do not display functioning due to persistent mood changes, which continues to cause occupation and interpersonal difficulties.

Signs and symptoms

The following signs and symptoms are indicative of bipolar disorder:

1. Presence or history of major depressive episodes:
   • Feeling sad or empty
   • Decreased interest in pleasure and daily activities
   • Weight changes (gain or loss)
   • Sleep changes (difficulty falling asleep or waking up)
   • Thinking and moving in an agitated or slowed manner
   • Feeling loss of energy or fatigued for most of the day
   • Feeling worthless or having unnecessary guilt for nearly every day
   • Decreased ability to think, concentrate, or indecisiveness nearly every day
   • Recurrent thoughts of death or suicide (without a plan or attempts)
2. Presence or history of at least one hypomaniac episode (persistent elevated or irritable mood lasting throughout at least four days). The criteria includes three or more of the following:
   • Grandiosity
   • Decreased requirement for sleep (patient feels rested after only three hours of sleep)
   • Pressure or overly talkative
   • Racing thoughts (flight of ideas)
   • Irrelevant distractibility (attention). The patient is easily distracted to something that is unimportant.
   • Increase in goal-directed activities
   • Excessive involvement with risky pleasurable activities (sexual indiscretions, buying sprees, or foolish monetary investments)
3. There is an uncharacteristic change in functioning
4. Mood and functioning changes are detected by others
5. Lacks severity since impairment is not pronounced
6. There has never been a manic or mixed episode. A mixed episode is characterized by a period of time, usually about one week in which the patient exhibits diagnostic criteria for both major depressive and manic episodes nearly every day. The criteria for manic and hypomanic episodes are identical.
7. The symptoms are severe to cause problems in occupation, social, and relationship functioning.
8. The symptoms are not associated with another medical condition, which can present with criteria similar to a manic episode.

For BT II to be chronic, criteria for the depressive episode should be met continuously for at least two years. Patients with concurrent catatonic features also exhibit disturbances with movement (immobility, peculiar or excessive motor activity). The features of BT II with melancholia often include near complete absence of the capacity for pleasure. Patients with BT II and atypical features usually present with mood reactivity (mood improves with positive event) and two or more of the following: increased appetite or significant weight gain; difficulty waking up from sleep; heavy, almost paralyzed feeling in the arms or legs; long term sensitivity to inter-personal rejection. BT II with postpartum onset usually occurs within four weeks after childbirth. Manic-depression with a seasonal pattern is also related to seasonal change, age, gender, and latitude. The prevalence of the seasonal specifier increases with higher latitudes, young persons, winter months, and female gender. Rapid cycler's are those who exhibit the criteria for BT II and have at least four episodes of a mood disturbance in the previous 12 months.