What is it?
Bipolar disorder is a mental disorder characterized by periods of depression and periods of mania. During the depressive periods the affected are very sad, angry, and uninterested in things they used to enjoy, and they often experience excessive guilt and hopelessness. During the manic periods the affected have an elevated or irritable mood, and sometimes this can present itself as euphoria.They can be easily distracted, take risks with things like gambling and sex, and sometimes they might experience grand illusions about, for example, being the “chosen one” on a mission to save the world.
About 3% of the US population is estimated to have bipolar disorder at some point in their lives. The disorder seems to affect both genders equally, and the average age of onset is 25.
What causes it?
It is thought that genetics account for 60-80% of the risk of developing bipolar disorder. Life events also play a significant role: for example, almost half of adults with bipolar disorder have reported traumatic or abusive childhood experiences.
What happens during it?
The mechanisms of bipolar disorder are little understood. It is thought, however, that it might be the result of a disruption in the development of the brain networks that regulate emotions. This is thought to lead to decreased connection between important areas.
The amygdalae are two almond-shaped structures deep inside our brain. They are highly involved in decision making, memory processing, and emotional reactions.
The ventromedial prefrontal cortex is an area in the cerebral cortex close to our forehead. It is involved in decision making, processing risk and fear, and the inhibition of emotional responses.
In short, it is thought that bipolar disorder might occur when the ventromedial prefrontal cortex is supposed to regulate the emotional reactions through the amygdalae, but fails to do so because the two aren’t adequately connected. Normally when our mood swings too far into some direction, the ventromedial prefrontal cortex interferes and brings it back to normal. In bipolar disorder, a trigger such as a very sad or a very exciting event might launch the affected straight into depression or mania.
How can it be treated?
Psychotherapy can be very useful with things like alleviating many symptoms and recognizing and learning to avoid the triggers that lead to episodes.
Treating bipolar disorder with medications can be tricky, though highly effective. Most people don’t respond to most drugs in the same way, and treating depression could trigger mania and the other way around. Lithium is perhaps the best established medication for treating and preventing manic episodes.
Sources: en.wikipedia.org/wiki/Bipolar_disorder, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3874804/#R2, en.wikipedia.org/wiki/Amygdala, en.wikipedia.org/wiki/Ventromedial_prefrontal_cortex, http://emedicine.medscape.com/article/286342-overview?pa=okFjCVMg%2BJ5h7uKSllzDfBskcNqENEZ7ffOEWeZFuUNqjaqRvE9UrKBRFk6JFkHELCEJNCrbkqLWYvqLrhntWA%3D%3D#a3, http://www.healthcentral.com/bipolar/c/15/176481/amygdala-bipolar-public-number/