The Most Common Bipolar Disorder Causes
Bipolar disorder (also called manic-depressive disorder) and unipolar depression are the most common debilitating mood disorders. While unipolar depression is characterized by unusually extended periods of sadness or despair, bipolar disorder causes erratic fluctuations in mood ranging from depression to periods of intensely high energy levels, aggressiveness, or expansiveness.
Typically, these two extremes occur in distinct periods called œmood episodes. These mood episodes occur along a wide spectrum, ranging from severe or mild depression to mild or severe mania.
For some people, bipolar disorder causes more deep depression periods, while they have less severe or frequent manic episodes. For others the opposite is true. A mixed episode is when bipolar disorder causes symptoms of depression and mania at the same time, and usually involves significant symptoms of irritability and agitation.
Bipolar disorder causes symptoms that often first present themselves during the late teen or early adult years. It is a serious disorder that can lead to strained personal relationships, difficulty at work and school, and even suicide in those with extreme mood symptoms. Usually the first episode is one of depression, so it is important not to automatically assume that a first or second episode of depression is unipolar, as frequently bipolar disorder causes depression that can suddenly switch to a manic episode with the use of certain medications, sleep deprivation, or bright light therapy.
Biological and Genetic bipolar disorder causes:
There is clearly a genetic component to bipolar disorder causes. The disorder appears to run in families. Perhaps the most convincing data comes from studies of twins, which indicate that if one twin has a mood disorder, an identical twin is about three times more likely than a fraternal twin to have a mood disorder as well (McGuffin P, et al Arch Gen Psychiatry 2003 May;60(5):497). If someone has one parent with bipolar disorder, they have a 13% risk of developing bipolar disorder at some point in their life; and an even higher risk if both parents have bipolar disorder (Birmaher B, et al. Arch Gen Psychiatry 2009 Mar;66(3):287). Interestingly, advanced paternal age has been associated with an increased risk of bipolar disorder of offspring, which may point towards a potential genetic mutation contribution (Frans Em, et al. Arch Gen Psychiatry 2008 Sep;65(9):1034).
Research emanating from the Genome Wide Association Study (GWAS) suggests that there is a polygenetic (multiple gene) contribution to an increased risk of bipolar disorder (Offord J. Pharmacology & Therapeutics 2011). In other words, there are likely several genes that increase the risk for developing bipolar disorder, with no one gene strong enough to cause bipolarity alone. Research shows that some genes associated with bipolar disorder code for ion channel proteins located on brain cells, and impact how various neurons communicate with one another via tiny electrical currents. This, in turn, probably effects the release or balance of chemical messengers, or neurotransmitters, in various parts of the brain. It is no surprise, then, that calcium channel blocker medications have been shown to relieve depression in patients with bipolar disorder.
The genetic risks of bipolar disorder increase the likelihood of various brain cells to interact abnormally, which likely results in malfunctioning neuro-circuitry and altered brain anatomy. Studies support this hypothesis; it appears that people with bipolar disorder, compared to those without, indeed tend to have problems with the connections and size of brain structures involved in mood regulation. For example, bipolar disorder has been associated with:
- A loss of gray matter (interestingly, treatment with Lithium can reverse this process)
- Alterations of white brain matter (axons)
- Aberrant connections between the cortex of the brain and the hippocampus
- Aberrant activity of the amygdala and the hippocampus when challenged with various memory and cognitive tests
Environmental Bipolar disorder causes:
Stressful life events, such as a death in the family or the loss of a job, are believed to be key triggers in some of the main bipolar disorder causes. Since every individual deals with stress differently, there is a not a specific definition of what life events lead to certain symptoms, but it is clear that stress is often related bipolar disorder causes.
Chaotic homes where people exhibit wide and unpredictable mood swings can trigger the onset of bipolar disorder causes in children who are presumably genetically vulnerable to bipolar disorder. Some studies have shown that people with bipolar disorder have a genetic predisposition to sleep cycle variances that may be responsible for the symptoms of depression and mania (Plante DT & Winkelman JW. Am J Psychiatry 2008;165:830-843). These studies indicate that many with bipolar disorder experience at least one sleep cycle disruption prior to a major mood episode.
Due to the multifactorial nature of bipolar disorder, ambiguity exists about exact bipolar disorder causes. Because those with a genetic risk of bipolar disorder are more vulnerable to also developing the condition, especially when triggered by a series of life stressors, it is important to get treatment as soon a possible in order to reduce negative effects on interpersonal and occupational functioning.
If you feel that you may be experiencing depression related to bipolar disorder causes, West Coast TMS Institute in Sherman Oaks, California is available to help you. Contact us if you feel you may be experiencing symptoms of depression or mania and would like to set up a psychiatric consultation.
If you found this post on the most common bipolar disorder causes interesting then you may be interested in our blog post on the most common bipolar disorder symptoms.