What Are the Chemicals That Cause Bipolar Disorder?

Bipolar disorder is a condition of severe mood swings that can affect energy levels and the ability to carry out daily activities. No direct cause has been associated with the condition, but several theories suggest that substances and chemicals in the brain play a vital role. Scientific evidence indicates differing levels of those chemicals in patients with bipolar disorder, compared with unaffected patients. If this is true, better treatment options could be found for bipolar patients.

Bipolar Disorder

• Bipolar disorder is a condition in which a patient will have mood disorders from high energy to low energy. The high-energy (manic) phase usually lasts at least a few weeks, followed by a period of balance, and then a low-energy (depressive) episode. In the manic state, a patient might become highly excitable and irritable, and exhibit poor judgment that could lead to self-injury or harm to others. She might also become heavily involved in several projects and ideas. During the depressive phase, the "polar" opposite can happen: low energy, low interest in daily activities, and even self-deprecating thoughts to the point of considering suicide. In fact, 10 to 15 percent of bipolar patients actually complete suicide.

Neurotransmitters and Dopamine

• Although a single cause of bipolar disorder cannot be determined, some chemicals in the brain, particularly neurotransmitters, appear at different levels in patients, compared with those without the disorder. Neurotransmitters are the chemicals responsible for exchanging information about specific functions within the brain, such as memory processing and operating the senses. In patients with bipolar disorder, levels of dopamine, a neurotransmitter that helps manage pleasure, are usually at levels higher than in nonpatients during a manic episode, and lower during depressive episodes. This isn't a confirmation that dopamine is the cause, but medications can be prescribed that help regulate these levels, which in turn helps regulate psychotic behaviors associated with bipolar disorder.

Proteins and Glutamate

• Certain proteins in the brain help cells and neurons survive. The cAMP response element binding-protein (CREB) helps activate protein kinase-A, which regulates sugar and glycogen levels in certain parts of the brain. One theory suggests that decreased CREB levels are associated with decreased volume in the brains of people with depression, insinuating that cell breakdown might contribute to depressive episodes in bipolar patients.
  Glutamate helps process the signal exchange between neurotransmitters and receivers. A "Science Daily" report on postmortem evaluation of the bipolar brain shows that patients with bipolar disorder tend to have high levels of glutamate in the brain, particularly in the prefrontal cortex, which hosts the cognitive functions.

Choline

• Choline is another neurotransmitter, one that helps transmit acetylcholine, which excites muscles in the body. The Brian Explorer website states that research demonstrates lower levels of choline in bipolar patients. There is also a suggested imbalance in activity between those transmitters and the catecholaminergic systems.

Substance Abuse

• Substance abuse can also affect the bipolar patient. Half of diagnosed patients, according to the Psycom website, struggle with substance abuse in an attempt to self-medicate. This affects the bipolar condition because some of those substances, including caffeine and nicotine, can interfere with medications designed to help the patient.