Scientists know that the brain conveys signals with electricity and chemicals, but how it accomplishes this feat at such prodigious speed is a mystery.
Research has shown that many people with bipolar disorder have a genetic predisposition for the illness, but stressful life events and upbringings can also trigger mood episodes.
The Hippocampus
The hippocampus, part of the brain’s limbic system, is important for memory and mood regulation. However, in people with bipolar disorder, researchers have found a significant volume decrease in specific areas of the hippocampus, including the cornu ammonis (CA1), CA2/3, and CA4, as well as the subiculum, presubiculum, and ML.
The finding, published in Molecular Psychiatry, supports the idea that hippocampal circuits are important for mood and memory processing. The study also suggests that a decline in these circuits may contribute to the recurrent depressive and manic episodes associated with bipolar disorder and a slower recovery rate between mood changes.
While genetics plays a role in bipolar disorder, a person’s environment can significantly affect whether or not they experience an episode. Stressful life events like divorce, the death of a loved one, job loss, and abuse of drugs or alcohol can trigger a mood episode or make a person more vulnerable to experiencing one.
Researchers have also found what is bipolar disorder. Usually, a person’s history of mood episodes influences the severity of their symptoms and how long they last. People with multiple episodes have more neuropsychological dysfunction, such as impaired verbal memory and slower executive function, than those who have never experienced an attack. This is known as illness neuroprogression, contributing to a worse course of the disease and a greater vulnerability to stress-related mood episodes.
Neurotransmitters
In bipolar disorder, chemical messengers are disrupted. These neurotransmitters carry signals between neurons across a gap in the brain called a synapse. They are essential for the brain to function and help control emotions, sleep, wakefulness, appetite, sexual activity, endocrine function and memory. In bipolar disorder, the neurotransmitter serotonin is particularly affected.
Neurotransmitters are found in millions of individual synapses throughout the brain. They are released from one neuron in a cyst or “sac” and then travel to the opposite side of the synapse, where they attach to a receptor designed to interpret a particular type of message. Once the message is delivered, the neurotransmitter can return to its source. There are three ways that communication with a neurotransmitter can be stopped. One way is that an enzyme can change its composition so it no longer carries a signal. Another is that the neurotransmitter can diffuse away from its receptor, and finally, the receptor can reabsorb a neurotransmitter.
Many researchers believe that BDNF is involved in bipolar disorder and other mood disorders. It is thought that a person’s genetics and the environment may also influence their chances of developing this disorder. It is known, for example, that people who have first-degree relatives with bipolar disorder are at a higher risk of developing the illness themselves. Stress can also play a role, as it can trigger manic or depressive episodes in many people.
Mitochondria
In people with bipolar disorder, the body appears to struggle to produce and break down certain brain chemicals – including adrenaline, dopamine, acetylcholine, serotonin and GABA (gamma-aminobutyric acid) – and hormones. These neurotransmitter imbalances are thought to cause mood changes ranging from hypomanic to depressive.
Several studies show that mitochondrial dysfunction may be involved in bipolar disorder. For example, alterations in the function of these vital organelles have been found both in brain imaging and post-mortem brains of people with bipolar disorder. It’s also been found that drugs that target the serotonin system effectively treat the condition.
Genetics plays a role in the development of the disorder, with research showing that 4 out of 5 people with the condition have a family history. It’s also been shown that some external factors, called triggers, can cause or make symptoms worse. These include hormonal changes, sleep disturbances, drug use and major life events.
Genetics
Scientists have identified several gene variants that increase the risk of bipolar disorder. However, the overall genetic contribution to the development of bipolar disorder is probably small. Many genes are involved, and they are likely to interact with environmental factors such as sleep patterns, family history of mental health problems and traumatic events like a death in the family or a divorce to determine whether or not someone will develop the condition.
Researchers have used large, multi-generational pedigrees to study the genetics of bipolar disorder. They have found that bipolar disorder tends to run in families and is caused by multiple gene mutations that accumulate over time. They have also seen that certain gene variants increase the risk of specific symptoms, such as mania or psychotic episodes.
However, it is important to remember that just because you have a genetic predisposition to developing bipolar disorder does not mean you will automatically get the illness. It is more likely that other factors will trigger the disease, including periods of high stress. These stresses may include major life changes such as moving, starting a new job or ending a relationship, financial troubles, arguments with friends and family members, physical illness, a head injury or losing a loved one.
*This is a collaboration post
