Bipolar disorder, also known as mania or manic depression, is characterised by episodes of extreme mood swings that alternate between very high excitable mood and very low depression, balanced by periods of “normal mood” in between. These extremes mood swings are thought to be due to over production of excitatory neurotransmitters like serotonin and dopamine.
Reducing neurotransmitter activity
Treatments for bipolar disorder use drugs that work by dampening down excitatory nerve transmission, which is the opposite effect to most antidepressants and has the effect of acting as a mood stabilizer. These drugs include lithium and carbamazepine.
Whereas most antidepressant medication increases the amount of mood enhancing neurotransmitters that cause symptoms of depression when deficient, lithium and carbamazepine work by blocking the action of sodium channels in nerve cell membranes that control the flow of sodium ions, which triggers the nerve cell to send out a nerve impulse. This reduces the release of mood enhancing neurotransmitters like serotonin, noradrenaline and dopamine, and helps prevent the recurrence of severe mood swings after an acute episode as well preventing or reducing the symptoms of mania.