Mood stabilizers are medications principally used in the treatment of bipolar disorder. Though their mechanism is not always known, they tend "stabilize" the mood by keeping patients from swinging between depressive and hypomanic or manic states. Their goal is to develop a euthymic or normal mood state. Some of these medications are used for other purposes. Moreover, they don't always achieve the same benefits for individual patients and they may be combined with other drugs for greater symptom control.
There are a number of different mood stabilizers, but those actually approved by the US Food and Drug Administration (FDA) for bipolar disorder make a short list. These are lithium and lamotrigine. Lithium is principally an anti-manic drug, though it appears to have good action in reducing depression in some bipolar disorder sufferers. Lamotrigine is more recent in development and also treats seizure disorders.
There are several anti-seizure medications, aside from lamotrigine, that are recognized for their mood-stabilizing properties. Though not FDA-approved for bipolar disorder, they are frequently prescribed off-label. Strong clinical evidences attests to their effectiveness.
In particular, carbamazepine and valproic acid or valproate may be chosen for mood stabilization. Another drug that is used is oxcarbazepine, which is very similar in chemical structure to carbamazepine. Gabapentin used to be classed as one of the anti-seizure mood stabilizers, but this was based on false data, and the drug is usually no longer recommended.
Each of the mood stabilizers has advantages and disadvantages, and individual patients react to them differently. Lithium is probably the most effective, but requires at least half-yearly blood testing to make sure levels are not too high. It can cause symptoms like cognitive dullness, nausea, and electrolyte imbalance. Lamotrigine doesn't need blood testing, but there is a small risk people will develop a very serious skin disorder called Stevens-Johnson syndrome while taking it. Carbamazepine and oxcarbazepine may require blood testing, and patients over time may metabolize these drugs more quickly, making them less effective.
Achieving mood stabilization may be possible through use of one of the mood stabilizers. Very often, people with manic-depressive disorder take more than one of these drugs, or they take other medications that may create more normal mood. Frequently chosen drugs for this purpose are newer antipsychotic drugs like quetiapine, risperidone, olanzapine, and ziprasidone. Other medications that may help to improve or stabilize mood include benzodiazepines. In rare cases, antidepressants are used, though this may promote a shift to manic or hypomanic states.
There are some other drugs being investigated for possible benefit as mood stabilizers. These include some calcium channel blockers and some beta-blockers. It can create worry among people with bipolar disorder that there are so few proven drugs to treat their condition. In a lifetime, it might be possible to wear out all the available choices. This concern certainly warrants continued drug research and clinical trials of available drugs that might have mood stabilizing properties.