Biology 202
2002 First Paper
On Serendip

It is generally understood that everyone has good and bad days. A phrase people are familiar with is "everyone has their ups and downs". Most people, to a certain extent, are able to control their moods, whether it is good or bad. However, people who suffer from bipolar disorder sometimes are unable to control their moods. People with bipolar disorder experience sudden and, at times, severe mood swings, shifting from manic to depressive moods. Bipolar disorder is not gender bias; both men and women are equally susceptible to it (3). About 1% of adults and children suffer from bipolar disorder, but this figure is probably not accurate because bipolar disorder is difficult to detect and is often misdiagnosed. The misdiagnosis often leads to the mistreatment of the disease (1).

People affected with bipolar disorder suffer from both mania and depression, experiencing manic symptoms, or extreme highs, and then suddenly experience depressive symptoms, or extreme lows. In between these mood swing episodes are periods of normal mood. The depressed mood often lasts longer than the manic mood, however, the duration of episodes vary from person to person. If left untreated, episodes can last from several days to several months. Some symptoms of mania are: increased energy, restlessness, rapid speech, racing thoughts, excessive euphoria, uncharacteristically bad judgment, denial, overspending money, and risky behavior. Some symptoms of depressions are: persistent sadness and anxiety, feelings of guilt, hopelessness, and pessimism, increased fatigue, loss of interest and pleasure, difficulty in concentrating and decision making, change in appetite, and thoughts of death and suicide. Sometimes, sufferers experience mixed episodes, when they feel both manic and depressive symptoms simultaneously (1).

Bipolar disorder can be classified into two categories, depending on the severity. Bipolar I disorder is used to classify sufferers who experience at least one mania or mixed episode each episode, and may or may not suffer from depression. Bipolar II disorder is used to classify sufferers who experience at least one depressive episode and at least on hypo mania (less severe than mania) episode. Those classified with bipolar II disorder do not experience a full manic episode or mixed episode. There are also different subtypes of bipolar disorder, depending on the frequency of the episodes. A person suffers from rapid cycling when he/she experiences four or more episodes per year. Ultra rapid cycling is similar to rapid cycling except the episodes occur more often, experiencing four or more episodes per week. Sometimes the occurrence of episodes may be predictable, or exhibit some sort of pattern. One of the patterns observed is the seasonal pattern. Observations show that the season, often spring or summer, affect the onset of episodes (1).

The cause of bipolar disorder is not completely known. Researches agree that there is a genetic component linked to the disorder. Studies show that first-degree relatives of people affected with bipolar disorder are about seven times more likely to develop bipolar disorder (4). Twin studies show if one identical twin has bipolar disorder, the second one has a 70% chance of developing the disorder within his/her lifetime. Despite the observations made, no specific gene has been located for the cause of bipolar disorder (5).

Molecular genetic researches hypothesize the cause may be abnormally programmed death among cells within the brain. Researchers are studying the affects of two chemicals used to treat bipolar disorder, lithium and valproate. Both these chemicals regulate the expression of a certain protein, the cytoprotective protein bcl-2, in the frontal cortex and hippocampus region of the brains in rats. Coincidentally, neuroimaging has shown that in that same region of the brain, affected individuals have a prominent number of cell loss. Based on these observations, researchers concluded that this abnormally programmed cell deaths might affect the expression of certain proteins, which in turn affect the critical brain circuitry that regulates emotions. Based on this hypothesis, antidepressants and mood stabilizers function by enhancing the cell survival pathways and improving cell resiliency (4).

The function of certain neurotransmitters has also been studied in relation to bipolar disorder. An electrical signal is needed for an action potential to travel across an axon of a neuron. The electrical signal is caused by a positive ion influx. Treatments for mania block the calcium channels of cell membranes. This shows that the different mood swings may be due to a disruption in calcium concentration in the neurons. A disruption in the neuron may also cause a disruption in the neurotransmitters. Those who suffer from bipolar disorder are shown to have an alteration in certain neurotransmitters. Some of these neurotransmitters include noradrenaline, dopamine, serotonin, and acetylcholine. Other factors such as drug abuse, head injury, and the surrounding environment are also speculated to influence the development of bipolar disorder (3).

Typically, drugs are used in combination of psychotherapy to treat bipolar disorder. Mood stabilizers are the standard form of drug treatment, and are used to treat manic, mixed, and hypo manic episodes. Lithium is the oldest and most prescribed mood stabilizer. It is usually the first drug prescribed after initial diagnosis of the disorder. In addition to mood stabilizers, anxiolytic may be prescribed to treat anxiety and insomnia, which is experienced during manic episodes (2). Anti-depressants are prescribed to treat depression. Some examples of anti-depressants are Tricycle's, SSRI's (Selective Serotonin Re-Uptake Inhibitors), and MAOI's (Monoamine Oxidase Inhibitor). For severe depression, ECT (Electro Convulsive Therapy) is used. Anti-depressants are usually taken in company with mood stabilizers, since taking anti-depressants alone can cause the patient to shift into a manic episode. Hospitalization may be necessary for additional supervision because affected people often feel suicidal or delusional (5).

Humans are complex organisms, unique from the other organisms of the animal kingdom. Humans are able to control their moods and thoughts. However, diseases like bipolar disorder takes this control away. It is diseases like this one which makes us reexamine the whole concept of brain=behavior. During manic-depressive episodes, the person control, and seems that a force more powerful than the person takes over his/her body and mind. It is uncertain to me if this "force" is the brain, or a force that overrides the brain. Since the cause of bipolar is still not completely known, my uncertainties and questions cannot be thoroughly answered.

WWW Sources
1) What is bipolar disorder?, on the Bipolar Home website
2)Mania, on the Bipolar website
3)Bipolar Education website
4)eMedicine Journal
5)Bipolar Home website

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