What is bipolar disorder?
Bipolar affective disorder, more commonly known as bipolar disorder, is a very common psychiatric illness. Also known as manic-depressive illness (MDI), bipolar disorder is characterized by episodes of prolonged depression that alternate with episodes of mania. Between these periods of mania and depression, usually there are periods of higher functionality, in which patients lead a productive life. Bipolar affective disorder leads to severe impairment of social and occupational function with a profound impact on interpersonal relationships.
How common is bipolar disorder?
In the United States, the lifetime prevalence (percentage of people with bipolar affective disorder at some point of time in their lives) is around 1.5%. Bipolar affective disorder usually starts between ages 15 to 25. It affects men and women equally; however, occurrence of four or more episodes annually is more common in women than in men.
Types of bipolar disorder
Bipolar affective disorder may be one of the following types.
Bipolar I disorder
Bipolar I disorder, which is mainly defined by a week’s long manic or mixed episodes, two weeks’ long depressive episodes, or by severe manic/depressive symptoms.
Bipolar II disorder
Bipolar II disorder, which is defined by episodes of depression shifting back and forth with episodes of hypomania (less severe form of mania) instead of full-blown mania.
Bipolar disorder not otherwise specified (BP-NOS)
Bipolar disorder not otherwise specified (BP-NOS), which is marked by shorter episode of symptoms or fewer symptoms that are not diagnosed under either of the previous two forms of the disorder.
Cyclothymic disorder, which is a mild compared to other forms, is marked by hypomanic episodes shifting back and forth with mild depression for at least 2 years.
Rapid-cycling bipolar disorder
This type, which is characterized by more than 4 episodes of major depression, mania/hypomania, or mixed symptoms in an year.
Bipolar Disorder Brain
The pathophysiology of bipolar disorder is not fully understood yet. However, bipolar affective disorder may have a genetic component to it, as twins and family members of an affected person are more likely to develop the condition.
Bipolar affective disorder usually results from changes in multiple different genes. Each of the involved genes may individually contribute relatively less to the development of the disease; however, the synergistic effect of hundreds to thousands of such genes can pose significant risk.
Three genes that play the most important roles in development of bipolar affective disorder are :
- CACNA1C (L-type voltage-gated calcium channel, alpha 1C subunit)
- ANK3 (ankyrin G)
CACNA1C and ANK3 are involved in regulation of proteins called voltage-gated channels, which are important to initiate the transmission of a signal. GSK3b affects the concentration of substances called neuroprotective factors and thus, controls cell death.
The nerve cells of the brain (neurons) are covered with a protective sheath called myelin, which also helps in transmission of the signals through them. In brains of patients suffering from bipolar affective disorder, the number of cells that produce myelin (oligodendrocytes) decreases. Loss of oligodendrocytes results in loss of myelin, which disrupts communication between neurons.
In patients with bipolar affective disorder, the areas of human brain that control emotions (ventral limbic regions) become very active. The levels of neurotransmitters (brain hormones) are either too high or low depending on the stage.
Signs and Symptoms
Symptoms of bipolar affective disorder can be grouped as following:
One or more of the following symptoms should be present for at least 1 week:
- Profound mood changes (like irritability, elation, or expansiveness)
- Symptoms not generated from any medical illness or by substance abuse
- Inflated self-esteem
- Reduced need for sleep
- Excessive talking
- Thoughts racing through the mind
- Goal-focused activities at home, at wor
- Excessive sexual drive
- Excessively pleasurable but dangerous activities
Major depressive episodes
Five or more of the following symptoms should be present for at least 2 weeks:
- Depressed mood
- Loss of pleasure or interest in all activities
- Drastic changes in appetite, body weight, activity levels, and need for sleep
- Loss of energy or fatigue
- Lack of concentration
- Suicidal thoughts
- Symptoms not generated from any medical illness or by substance abuse
Marked changes in personality are common in patients with bipolar affective disorder, and may include the following:
- Poor or no eye contact during depression
- Wearing unkempt, dirty, creased and ill-fitting clothes
- Dirty nails
- Sadness, hopelessness, and helplessness
- Talking in low tones or in depressed/monotone voices
- Presence of delusions and hallucinations in some cases
- Busy, active, and involved look during hypomania
- Hyperactivity, aggressiveness, impatience, and hypervigilance
- Fast talking and acting
- Bright, colorful, garish, yet disorganized clothes
- Joyous, jubilant or irritable mood
Causes and Risk Factors
Following factors may contribute to bipolar disorder:
- Genetic factors include involvement of the ANK3, CACNA1C, and GSK3b genes.
- Relatives are approximately 7 times more likely to develop the condition.
- Loss of myelin-producing oligodendrocytes.
- Abnormal levels of brain chemicals (neurotransmitters) like serotonin, glutamate, nor-epinephrine, and dopamine.
- Hormonal imbalances due to problems in hypothalamic-pituitary-adrenal axis.
- Hyperactive ventral limbic brain regions.
- Severe emotional stress (like one arising from pregnancy in women with a history of manic-depressive illness).
Tests and Diagnosis
Biplar affective disorder should be diagnosed by a mental health professional, like a psychiatrist or psychologist. There are specific criteria that needs to be met as outlined in the Diagnostic and Statistical Manual of Mental Disorders (DSM) in order for bipolar affective disorder to be diagnosed. The following tests can be performed to assist in the diagnose of bipolar disorder:
- Lab tests: Blood samples are tested to rule out other causes of depression (like anemia, changes in sodium or calcium levels, kidney failure) and psychosis (like an infection, lupus), alcohol/drug abuse.
- Imaging studies: A magnetic resonance imaging (MRI) scan can reveal changes in brain areas.
- Electroencephalography: An EEG can be used to rule out a brain tumor and seizure disorder.
Treatment of Bipolar Disorder
Treatment depends upon the phase of the episode (that is, depression or mania) and the severity of the phase. Hospitalization is recommended if patients pose danger to themselves or others, are unable to function, are out of control, or have medical conditions that require monitoring the medications. Day treatment is recommended fo patients with severe symptoms but presence of control and a stable living environment. Outpatient treatment includes psychotherapy, which aims to teach the ways to handle the stress. The medication can also be monitored.
- Antipsychotics (such as valproate and benzodiazepines like lorazepam and clonazepam) are given for treating an acute manic episode. However, benzodiazepines have sedative effects.
- Antidepressants (such as quetiapine, olanzapine, carbamazepine, or lamotrigine) are given to untreated depressed patients.
- Lithium is frequently given to prevent and treat manic episodes. However, causes side-effects like loss of urinary concentrating ability, hypothyroidism, weight gain, and hyperparathyroidism. For patients taking a mood-stabilizing agent like lithium, lamotrigine is given.
- Drugs called atypical antipsychotics (like ziprasidone, risperidone, quetiapine, aripiprazole, asenapine, and olanzapine) are given to stabilize acute mania or to treat bipolar depression in some patients.
- Haloperidol may also be given for treating acute mania.
Electroconvulsive therapy (ECT) is very effective in the treatment of acute mania.
Patients suffering from depression are encouraged to exercise.
Complications and Prognosis
The main complications of bipolar disorder are suicide, homicide, and addictions. The risk of suicidal behavior is higher in women, in people with a history of alcohol or substance abuse, in people with young age of onset, severely depressed patients, and patients on benzodiazepines.
In the United States, 25 to 50% of individuals with bipolar affective disorder attempt suicide, and 11% end their lives by committing suicide.
Poor job history, male gender, alcohol abuse, and presence of psychotic and depressive features worsen the prognosis. However, shorter manic phases, late age of onset, and fewer suicidal thoughts, psychotic symptoms, and medical problems improve the prognosis.