Mood stabilizer medications

Date: 1949 forward

Type of psychology: Psychopathology

Although the term “mood stabilizers” is clinically imprecise, these medications remain an essential part of treatment for several mood and thought disorders.

Introduction

Typically, most medications used to treat bipolar disorder and related mood disorders—such as cyclothymia—are popularly called mood stabilizers. A more clinically precise use of the term would refer only to medications that decrease mania, alleviate depression, and provide long-term protection against relapse. Given this qualification, the most commonly used mood stabilizers are lithium and two anticonvulsants, valproic acid (Depakote, Depakene, Depakon) and carbamazepine (Tegretol, Carbatrol).

How They Work

Central nervous system medications work by regulating the effects of a group of chemicals used to relay signals throughout the brain. In simple terms, neurotransmitters relay signals after being released into the physical gaps between a neuron and its neighbors. In these gaps, neurotransmitters stimulate receptors on neighboring cells, which prompts processes within those cells. One of these processes, for example, is the production of secondary chemicals, called second messengers.

Although precisely how lithium works is unknown, it is believed either to alter the synthesis of neurotransmitters associated with altered moods, or to decrease the production of second-messenger chemicals. Valproic acid and carbamazepine appear to work by decreasing the excitability of neurons or by increasing the effectiveness of a neurotransmitter associated with calm, tranquillity, and relaxation.

Lithium

Lithium is a naturally occurring element and in various formulations is the drug of choice for treating euphoric mania. In this mood state, people experience increased energy and decreased need for sleep, impaired judgment and impulse control, irritable moods, and in extreme cases delusions or hallucinations.

As a mood stabilizer, lithium reduces elation, grandiosity, irritability, and anxiety. It also helps control insomnia, agitation, threatening or assaultive behavior, and distractibility. Although it is not otherwise useful in the depressive phases of bipolar disorder, lithium reduces suicidal thinking. Besides bipolar disorder, lithium has been used in schizoaffective disorder and schizophrenia, as well as in impulse control disorders involving unplanned outbursts of violence and rage.

Like all other mood stabilizers, lithium takes effect only after accumulating in the blood to certain levels, called the therapeutic window. When the level is too low, lithium will not have a notable effect; if the level is too high, the person taking it will experience toxicity. Reaching a therapeutic level with lithium usually takes between seven days and two weeks. At therapeutic levels, lithium’s most common side effects include gastrointestinal upset, fine tremors, increased urination, and fatigue. Some of these side effects go away on their own, others can be easily treated. Potential long-term side effects include weight gain and cognitive dulling.

Unfortunately, lithium has a narrow therapeutic window, meaning that dosages must be carefully adjusted to avoid toxicity. Even with recommended blood tests, toxicity is sometimes detected symptomatically. Low toxicity is often indicated by nausea and vomiting, diarrhea, thirst, slurred speech, and muscle weakness. Severe toxicity is signaled by coarse hand tremors, confusion, hyperactive muscles and reflexes, cardiac problems, and loss of coordination. Extreme toxicity is marked by seizures, coma, cardiac arrhythmia, circulatory collapse, and death as a result of pulmonary failure.

Maintaining a therapeutic lithium level can be difficult with certain environmental or lifestyle conditions. When hot weather, strenuous exercise, or prolonged diarrhea leads to dehydration, the kidneys retain lithium, which can lead to toxicity. Adequate water intake usually prevents this. Moreover, other drugs—such as ibuprofen—can raise lithium levels.

People with dementia and neurological disorders do not respond well to lithium. Likewise, it is contraindicated for people with brain damage, myasthenia gravis, or cardiovascular, renal, or thyroid disease. Further, lithium is contraindicated in women who are breast feeding or who are pregnant or become pregnant. The Food and Drug Administration (FDA) recommends avoiding lithium during pregnancy, especially the first trimester. Several studies have demonstrated a link between lithium and fetal damage, including severe cardiac problems and deformation.

The Anticonvulsants

In the 1980s, scientists discovered that a number of medications used to treat epilepsy demonstrated remarkable efficacy in bipolar disorder. Many anticonvulsants are now used for manic or depressed moods, although only two of them have been approved by the FDA for treating bipolar disorder.

Valproic Acid

In 1995, valproic acid (Depakote, Depakene, Depakon) became the first anticonvulsant approved by the FDA for the treatment of mania. It has become the preferred medication over lithium for most types of bipolar disorder. Generally speaking, valproic acid works faster, has a wider therapeutic window, and fewer overall side effects.

Like lithium, gastrointestinal distress is a common side effect with valproic acid, except in formulations with enteric coatings. More serious side effects include potential damage to the liver and the pancreas, as well as decreased platelet counts. Most significantly, valproic acid is harmful to the human fetus and is absolutely contraindicated in pregnant women.

Carbamazepine

Carbamazepine (Tegretol, Carbatrol) received FDA approval in 2005. Some side effects include visual disturbances, ataxia, vertigo, and other neurological side effects. Although these side effects are common, they are usually transient. More significantly, carbamazepine has been associated with decreased white blood cell count and decreased platelet count. Hence, blood cell counts must be monitored in patients using the drug. Further, carbamazepine can accelerate the metabolism of other medications, including oral contraceptives, blood thinners, and certain kinds of antidepressants. As a result, doses of these other medications must be reevaluated.

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