Bipolar Disorder Essays

Submitted By CAVICK7961
Words: 924
Pages: 4

Bipolar Disorder
Catherine Vick
PSY350: Physiological Psychology
Wayne Briner
March 1, 2015

Bipolar Disorder Bipolar disorder is characterized by transitions between depression and mania or hypomania depending on the severity. Individuals who experience manic episodes also experience depressive episodes or symptoms, or mixed episodes in which both mania and depression are present at the same time. These episodes are usually separated by periods of "normal" mood, but in some individuals, depression and mania may rapidly alternate, known as rapid cycling. Over 3 million Americans, about 1% of the population, or 1 in every 100 people, suffer from bipolar disorder, with similar rates in other countries. Bipolar disorder occurs equally among males and females, and often begins between the ages of 15 and 24. While the exact cause of this disorder remains unclear, there are several factors that are known to contribute to its development such as genetics, physiological, environmental, neurological, and nueroendocrinological. Genetic influences are believed to account for 60 to 80% of the risk for developing bipolar disorder. Although scientists have been unable to pin point a specific gene responsible for the disorder, their findings have concluded that variants within the genes CACNA1C, ODZ4, and NCAN can be a major factor in its development. An increase in these genetic mutations has been linked to advanced paternal age leading to an increased risk of bipolar disorder development in offspring (Kerner 2014). Physiological influences including abnormalities in the structure and function of certain brain circuits also plays a major role in the development of bipolar disorder. Brain imaging studies have proven an increase in the volume of the lateral ventricles, globus pallidus, and rates of deep white matter hyper intensities. They also suggest that abnormal modulation between ventral

prefrontal and limbic regions, including the amygdala, contribute to poor emotional regulation and mood instabilities. Alterations to the mitochondria and sodium ATPace pump are also believed to cause poor neuron firing and hypersensitive neuron firing resulting in periods of depression and mania (Goodwin & Jamison 2007). Scientific evidence also seems to suggest that environmental factors combined with physiological abnormalities in people genetically predisposed for bipolar disorder, raises the risk factor significantly. 30 to 50% of adults diagnosed with bipolar disorder report traumatic experiences during childhood. “There is evidence supporting an association between early-life stress and dysfunction of the hypothalamic-pituitary-adrenal axis (HPA axis) leading to it’s over activation, which may play a role in the pathogenesis of bipolar disorder (Sedler 2010).” Neurological condition or injury, though less common, has also been known to lead to bipolar disorder development. These conditions include; temporal lobe epilepsy, stroke, brain injury, multiple sclerosis, porphyria, and HIV infection. Though these conditions or injuries are less likely to cause bipolar disorder, it can develop over time depending on the severity of the damage and the area of the brain affected by the trauma. Scientists have determined that there are three neurotransmitters involved in this disorder, dopamine being the first. Dopamine is responsible for mood regulation, and has increased transmission during the manic phase. “The dopamine hypothesis states that the increase in dopamine results in secondary homeostatic down regulation of key systems and receptors such as an increase in dopamine mediated G protein-coupled receptors (Sedler 2010).” This decrease in dopamine

transmission causes the depressive phase, and when the depressive phase ends, the cycle starts over again. Glutamate and gamma-amino butyric acid (GABA), the other neurotransmitters involved, cause elevated mood states. Glutamate increases in the left…