Mood stabilizers explained

What mood stabilizers are

A mood stabilizer is a medication that evens out mood and helps prevent the episodes of bipolar disorder. Bipolar disorder involves episodes at both poles, the highs of mania or hypomania and the lows of depression. A mood stabilizer works to reduce both, and to keep mood within a steadier range over time.

Mood stabilizers are a mixed group, not a single type of drug. The main ones are lithium, which is the oldest and still a benchmark, and several anticonvulsant medications used for mood: lamotrigine (Lamictal), valproate, also called divalproex (Depakote), and carbamazepine (Tegretol). Some atypical antipsychotic medications are also used to stabilize mood, but they are usually grouped separately.

How they work

How mood stabilizers work varies across the group, and no single explanation covers all of them.

Lithium is a naturally occurring element, taken as a simple salt. Despite decades of use, exactly how it stabilizes mood is still not fully understood. It is known to affect several signaling pathways inside nerve cells, the chemical steps a cell uses to pass along and respond to messages, and researchers think those effects gradually steady the brain systems involved in mood.

The anticonvulsants in the group, including lamotrigine, valproate, and carbamazepine, were first developed to treat seizures. They calm excessive nerve signaling. Lamotrigine, for example, reduces the release of glutamate, an excitatory chemical messenger that nerve cells use to pass signals. The honest summary across the whole group is that these medications clearly help many people, and the precise mechanism is still being studied.

How the class developed

The story of mood stabilizers starts with lithium. In 1949, the Australian psychiatrist John Cade identified lithium's mood-stabilizing effect. It was a striking finding, and it took time for the rest of the field to build on it and confirm it. Lithium was approved in the United States for mania in 1970, and it has remained a benchmark ever since.

The group grew from there. Over the following decades, several anticonvulsant medications, drugs first developed to treat seizures, were found to help stabilize mood. Valproate, carbamazepine, and lamotrigine each joined the group of medications used for bipolar disorder. More recently, several atypical antipsychotics were also found to help steady mood. The result is the mixed group used today, built around lithium as the original and still central member.

What they are used for

Mood stabilizers are used mainly for bipolar disorder. They have two distinct roles, and both matter.

The first is treating acute episodes. A mood stabilizer can help bring a current manic or depressive episode under control, though the speed and the strength of that effect depend on the specific drug.

The second role is maintenance treatment, and it is a central reason these medications are taken. Maintenance means taking the medication over the long term to prevent future episodes. The benefit here is something that does not happen, an episode avoided, so it is measured over months and years rather than days. Many people stay on a mood stabilizer long after they feel well, because feeling well is often a sign the medication is doing its job.

Beyond bipolar disorder, some mood stabilizers are added to an antidepressant in depression that has been hard to treat. Lithium in particular has good evidence in that role.

What they have in common

The medications in this group share several things.

• They are long-term maintenance medications, taken to prevent episodes over time, not just to treat a current one.
• They need a careful, individualized approach to dosing.
• Several of them require blood tests, both to check medication levels and to monitor organs such as the kidneys, thyroid, or liver.
• Stopping any of them abruptly can destabilize mood and raise the risk of an episode, so they need a gradual, planned taper.
• They are most effective when the diagnosis behind them is accurate, which is why diagnosis gets its own discussion below.

How they differ from each other

The mood stabilizers are not interchangeable. The differences below shape which one fits a given person.

• Lithium is the benchmark. It has broad effectiveness across both poles of bipolar disorder, and it has strong evidence behind it, including good evidence for reducing the risk of suicide. The trade-off is that it has a narrow therapeutic range, meaning the blood level that works and the level that becomes toxic are close together. Lithium needs regular blood tests, plus periodic checks of kidney and thyroid function.
• Lamotrigine is strongest at preventing the depressive pole of bipolar disorder, which is where it stands out. It is relatively weight-neutral. It must be started at a low dose and increased very slowly over several weeks, because a faster increase raises the risk of a rare but serious skin reaction.
• Valproate is effective for mania and needs monitoring, including blood tests. It can cause weight gain. It carries a pregnancy caution and is generally avoided in pregnancy and in people who could become pregnant, because of a risk of birth defects.
• Carbamazepine is effective, but it interacts with many other medications, which can make it harder to combine with other treatments and requires careful coordination.

How a prescriber chooses one

Choosing a mood stabilizer starts with the clinical picture. The most important question is which pole needs the most attention. Someone whose main problem is recurring depression may do well on lamotrigine, given its strength at preventing depressive episodes. Someone in or prone to mania may be better served by lithium or valproate, which act more directly on the manic side.

Beyond the symptom pattern, a prescriber weighs several practical factors. These include a person's history of suicide risk, where lithium's evidence is a real consideration, the willingness and ability to keep up with regular blood tests, side effects that matter to the individual such as weight gain, other medical conditions, other medications and their interactions, and whether the person is pregnant or planning a pregnancy. Lithium remains the benchmark and is often the first choice, but the right answer is the one that fits the person, and it is a decision worth talking through carefully.

It is also worth noting that some atypical antipsychotics are used to stabilize mood, sometimes on their own and sometimes alongside a mood stabilizer, so the full set of options is broader than this group alone.

A note on diagnosis

An accurate bipolar diagnosis matters more here than almost anywhere else in psychiatry. Mood stabilizers are central to treating bipolar disorder, and the diagnosis shapes the whole treatment plan. An antidepressant taken alone can sometimes destabilize mood in someone who has bipolar disorder, which is one reason getting the diagnosis right is so important. The diagnosis is the foundation, and the choice of medication is built on top of it.

The medications in this class

• Lithium. The oldest mood stabilizer and still a benchmark. Broadly effective, with good evidence for reducing suicide risk. It has a narrow therapeutic range and needs regular blood tests plus kidney and thyroid monitoring.
• Lamotrigine (Lamictal). A mood stabilizer that is strongest at preventing depressive episodes. It needs a slow dose increase and is relatively weight-neutral.
• Valproate (divalproex, Depakote). An effective treatment for mania that needs monitoring, can cause weight gain, and is generally avoided in pregnancy.
• Carbamazepine (Tegretol). An effective mood stabilizer that interacts with many other medications.

PsychiatryRx has dedicated guides for several of these, with more detail on their uses, side effects, dosing, and what to expect.

Common questions

What is the difference between a mood stabilizer and an antidepressant? An antidepressant treats depression by lifting low mood. A mood stabilizer works on both poles of bipolar disorder, easing mania as well as depression, and it is used over the long term to prevent future episodes. In bipolar disorder, an antidepressant taken alone can sometimes push mood toward mania, which is one reason a mood stabilizer is usually central to treatment.

Why does lithium need blood tests? Because lithium has a narrow therapeutic range. The blood level that works and the level that becomes toxic are close together. Regular blood tests confirm the level is in the safe, effective zone. They also check that the kidneys and thyroid, which lithium can affect over time, are doing well.

Is one mood stabilizer the best? No single one is best for everyone. Lithium is the benchmark and has the broadest evidence, including for reducing suicide risk. But lamotrigine may suit someone whose main problem is depression, and valproate may suit someone with prominent mania. The best choice depends on the symptom pattern, the side effects a person can accept, monitoring needs, and other health factors. It is a decision to make with a prescriber.

Sources

This guide draws on current prescribing information and public health references. It is reviewed for clinical accuracy and updated as guidance changes.

1. U.S. Food and Drug Administration. Prescribing information.
2. MedlinePlus, U.S. National Library of Medicine.
3. National Institute of Mental Health. Mental health medications.