Lithium is a prescription mood stabilizer primarily used to treat bipolar disorder, helping reduce episodes of mania and lower the risk of future mood episodes. In some cases, it is also prescribed alongside other medications for treatment-resistant depression. Because lithium has a narrow therapeutic range, it requires regular blood tests and ongoing medical supervision to help ensure it remains both safe and effective.
If you’ve recently been prescribed lithium or are exploring treatment options for yourself or someone you care about, it’s natural to have questions about why this medication is used and what to expect. Lithium has been a cornerstone of psychiatric care for decades and remains one of the most well-studied medications for managing mood disorders. Although newer medications are available, many mental health professionals continue to recommend lithium because of its proven ability to stabilize mood and help prevent future episodes in appropriate patients.
The primary use of what is lithium used for in mental health centers on treating bipolar disorder, particularly episodes of mania and long-term maintenance therapy. Healthcare providers may also prescribe lithium as an add-on treatment when depression has not improved with antidepressants alone. Since every person’s medical history and symptoms are different, the decision to prescribe lithium is based on a comprehensive psychiatric evaluation rather than a single diagnosis.
Like many psychiatric medications, lithium works best as part of a broader treatment plan that may also include psychotherapy, healthy lifestyle habits, and regular follow-up appointments. Ongoing medication management helps clinicians monitor effectiveness, adjust dosage when needed, and identify potential side effects early. If you’re wondering who is qualified to prescribe and monitor psychiatric medications, our guide on Who Can Prescribe Mental Health Medication? explains the healthcare professionals involved in medication management.
Although lithium can be highly effective, it is not the right treatment for everyone. Understanding how it works, which conditions it treats, its potential benefits, and the importance of regular monitoring can help you have informed conversations with your healthcare provider and make confident decisions about your mental health care.
What Is Lithium Used for in Mental Health?
Lithium is primarily used to treat bipolar disorder, where it helps control episodes of mania and reduces the likelihood of future mood episodes. It may also be prescribed alongside other medications for some people with treatment-resistant depression when standard antidepressants have not provided enough relief. Because lithium affects the body differently than many other psychiatric medications, treatment requires regular monitoring by a healthcare provider.
The main reason clinicians prescribe what is lithium used for in mental health is its ability to stabilize mood over both the short and long term. During manic episodes, lithium can help reduce symptoms such as unusually elevated mood, increased energy, racing thoughts, impulsive behavior, and a decreased need for sleep. Once symptoms improve, many people continue taking lithium as maintenance therapy to help prevent future episodes of mania or depression.
One feature that distinguishes lithium from many other mood stabilizers is its long history of clinical use. Decades of research and experience have shown that it can reduce the frequency and severity of mood episodes in many people with bipolar disorder. Because of this strong evidence, many psychiatric guidelines continue to recommend lithium as a first-line treatment for bipolar disorder, particularly for long-term mood stabilization.
Healthcare providers may also consider lithium as an adjunctive treatment, meaning it is used together with another medication rather than on its own. For example, some individuals with major depressive disorder who have not responded adequately to antidepressants may benefit from adding lithium to their treatment plan. This approach is carefully individualized after considering the person’s symptoms, medical history, and response to previous treatments.
Although lithium has several important psychiatric uses, it is not appropriate for every mental health condition. A healthcare provider will evaluate factors such as the diagnosis, kidney and thyroid health, current medications, pregnancy status, and the person’s ability to attend regular follow-up appointments before recommending lithium. These considerations help balance the medication’s potential benefits with its safety requirements.
Rather than viewing lithium as a medication that treats symptoms, it is more accurate to think of it as part of a comprehensive treatment plan. When combined with psychotherapy, healthy lifestyle habits, and ongoing medication management, lithium can help many people achieve greater mood stability and improve their quality of life.
How Lithium Helps Stabilize Mood
Lithium helps stabilize mood by influencing communication between brain cells and supporting the balance of chemical signaling involved in mood regulation. Although researchers do not fully understand every aspect of how it works, clinical evidence shows that lithium can reduce the intensity of manic episodes, lower the risk of relapse, and help maintain more consistent mood over time.
Unlike medications that target a single brain chemical, lithium appears to affect several biological processes involved in emotional regulation. It influences the activity of neurotransmitters—chemical messengers that allow nerve cells to communicate—and may also support healthy signaling pathways inside brain cells. These combined effects are thought to help reduce the extreme mood fluctuations seen in bipolar disorder.
Another important aspect of lithium treatment is that its benefits often extend beyond managing an active mood episode. After symptoms improve, many people continue taking lithium as maintenance therapy to help prevent future episodes of mania or depression. Maintaining stable mood over time can reduce disruptions to work, school, relationships, and daily functioning.
Lithium does not produce immediate results. During an episode of acute mania, improvement may begin within several days, but the full therapeutic effect often develops over one to three weeks. When lithium is prescribed for long-term mood stabilization or as an add-on treatment for depression, it may take several weeks before its full benefits become apparent. Healthcare providers may temporarily use other medications alongside lithium while waiting for it to reach its therapeutic effect.
For lithium to work safely, the amount of medication in the bloodstream must remain within a relatively narrow therapeutic range. If the level is too low, it may not adequately control symptoms. If it becomes too high, the risk of side effects and toxicity increases. For this reason, healthcare providers schedule regular blood tests to measure lithium levels and adjust the dosage when needed.
Several everyday factors can affect lithium levels. Dehydration, significant changes in salt intake, vomiting, diarrhea, fever, or certain medications—including some nonsteroidal anti-inflammatory drugs (NSAIDs), diuretics, and blood pressure medications—can alter how the body processes lithium. Patients are typically advised to stay well hydrated, maintain a consistent diet, and inform their healthcare provider before starting any new prescription, over-the-counter medication, or supplement.
Because of its unique mechanism and monitoring requirements, lithium should always be taken exactly as prescribed. Changing the dose or stopping the medication without medical guidance can increase the risk of symptom recurrence and, in some cases, trigger a relapse of bipolar disorder. Regular follow-up appointments allow healthcare providers to evaluate treatment effectiveness, monitor for side effects, and make adjustments that support both safety and long-term symptom control.
Bipolar Disorder
Bipolar disorder is the primary mental health condition for which lithium is prescribed. It is considered one of the most effective long-term treatments for Bipolar I disorder and is also used for some people with Bipolar II disorder, depending on their symptoms and treatment history. By helping stabilize mood, lithium can reduce both the severity of active episodes and the likelihood of future relapses.
During a manic episode, a person may experience unusually elevated or irritable mood, increased energy, racing thoughts, rapid speech, impulsive decision-making, and a reduced need for sleep. These symptoms can interfere with relationships, work, finances, and personal safety. Lithium is commonly prescribed to help control mania and restore mood stability, although additional medications may sometimes be needed when symptoms are severe.
After recovery from an acute episode, lithium is often continued as maintenance therapy. This long-term approach aims to prevent new episodes of mania and depression rather than simply treating symptoms when they occur. For many people with bipolar disorder, consistent maintenance treatment can reduce the frequency of mood episodes and improve overall functioning, making it easier to maintain daily routines, employment, and relationships.
One reason lithium remains widely used is its strong evidence for reducing the risk of suicide and suicide attempts among people with bipolar disorder. While no medication can eliminate suicide risk entirely, research has consistently shown that lithium offers a protective benefit that is not observed to the same degree with many other mood stabilizers. This makes it an especially important treatment option for some individuals when healthcare providers determine it is appropriate.
Not everyone with bipolar disorder is an ideal candidate for lithium. Before prescribing it, clinicians consider factors such as kidney function, thyroid health, pregnancy plans, existing medical conditions, current medications, and the person’s ability to attend regular follow-up visits for blood testing. These evaluations help ensure that the potential benefits outweigh the risks and that treatment can be managed safely over time.
Although lithium has long been regarded as the gold standard for long-term treatment of bipolar disorder, it is only one part of comprehensive care. Many people also benefit from psychotherapy, education about recognizing early warning signs of mood changes, healthy sleep habits, stress management, and support from family or caregivers. Combining medication with these strategies can improve long-term outcomes and help individuals better manage the challenges of living with bipolar disorder.
Depression as Add-On Treatment
Lithium may also be prescribed as an adjunctive treatment for treatment-resistant depression, meaning it is added to an antidepressant rather than used by itself. This approach is generally considered when a person with major depressive disorder (MDD) has not experienced enough improvement after trying one or more antidepressant medications at an appropriate dose and duration.
Unlike bipolar disorder, where lithium is a well-established first-line mood stabilizer, its role in depression is more selective. Mental health providers typically consider lithium augmentation after reviewing previous treatments, current symptoms, medical history, and any factors that could affect the medication’s safety. The decision is individualized and based on a careful assessment of the potential benefits and risks.
For some people, adding lithium may enhance the effectiveness of an antidepressant and improve symptoms that have remained persistent despite treatment. Research has shown that lithium augmentation can be beneficial for certain individuals with treatment-resistant depression, although it does not work for everyone. Because responses vary, healthcare providers monitor symptoms closely after lithium is introduced and adjust the treatment plan if needed.
When lithium is prescribed for depression, regular monitoring remains just as important as it is for bipolar disorder. Blood tests help confirm that lithium levels stay within the therapeutic range, while routine evaluations of kidney and thyroid function support the safe use of the medication over time. Follow-up appointments also allow healthcare providers to assess symptom improvement, identify side effects early, and determine whether ongoing treatment is appropriate.
Lithium is rarely the only intervention for treatment-resistant depression. It is commonly combined with psychotherapy, lifestyle modifications, and other evidence-based treatments to address the many factors that can influence recovery. Depending on an individual’s clinical needs, a psychiatrist may also consider other augmentation strategies or alternative medications before deciding that lithium is the most suitable option.
Although lithium can play an important role in managing difficult-to-treat depression, it should only be used under the supervision of a qualified healthcare provider. Self-adjusting the dosage or discontinuing the medication without medical guidance can increase the risk of relapse and may complicate future treatment. Careful monitoring and open communication with the prescribing clinician help maximize the potential benefits while maintaining patient safety.
Other Psychiatric Uses
In addition to its established role in bipolar disorder and its use as an add-on treatment for some cases of depression, lithium may occasionally be prescribed for other psychiatric conditions. These uses are generally considered off-label, meaning they are supported by clinical experience or evidence in selected situations but are not approved by the U.S. Food and Drug Administration (FDA) for those specific conditions. A psychiatrist will only consider these options after carefully evaluating the individual’s symptoms, medical history, and response to previous treatments.
One example is schizoaffective disorder, a condition that combines symptoms of schizophrenia with mood episodes such as mania or depression. For some individuals whose illness includes significant mood instability, lithium may be used alongside antipsychotic medication to help manage the mood-related aspects of the condition. The exact treatment plan depends on which symptoms are most prominent and how the person responds to therapy.
Lithium may also be considered for people who experience recurrent mood episodes that have not responded adequately to other mood stabilizers or whose symptoms continue despite standard treatment. In these situations, the decision to prescribe lithium is highly individualized and based on a thorough review of potential benefits, possible side effects, and the person’s ability to participate in ongoing monitoring.
Although researchers continue to study lithium’s effects in other neurological and psychiatric conditions, evidence is not yet strong enough to recommend it routinely outside established clinical indications. Healthcare providers rely on current treatment guidelines and the best available scientific evidence when deciding whether an off-label use is appropriate. Patients should not expect lithium to be prescribed simply because it has shown promise in early research.
Because off-label prescribing involves careful clinical judgment, patients need to discuss the reasons for treatment, expected benefits, possible risks, and available alternatives with their healthcare provider. Understanding why a medication has been recommended can help patients participate more actively in shared decision-making and feel more confident about their treatment plan.
Regardless of the condition being treated, lithium should always be taken exactly as prescribed and monitored regularly through follow-up appointments and laboratory testing. This ongoing supervision helps ensure that treatment remains safe while allowing healthcare providers to adjust the dosage if changes in health, medications, or lifestyle affect lithium levels.
Benefits of Lithium Treatment
Lithium offers several well-established benefits for people with certain mood disorders, particularly bipolar disorder. Its greatest strength lies in helping stabilize mood over the long term, reducing the frequency and severity of manic and depressive episodes. When prescribed appropriately and monitored regularly, lithium can improve daily functioning and support long-term recovery.
One of lithium’s most important benefits is its ability to help prevent relapse. Bipolar disorder is often a lifelong condition characterized by recurring mood episodes, even after symptoms improve. Continuing lithium as maintenance therapy can lower the likelihood of future episodes, allowing many individuals to experience longer periods of emotional stability and maintain their personal, social, and professional responsibilities.
Another distinguishing benefit is lithium’s association with a reduced risk of suicide and suicide attempts in people with bipolar disorder. Clinical research has consistently found this protective effect, making lithium unique among many psychiatric medications. Although it is not a substitute for comprehensive mental health care or crisis intervention, this evidence is one reason healthcare providers may recommend lithium for individuals whose clinical history suggests they could benefit from long-term mood stabilization.
Lithium may also improve overall quality of life by helping reduce the disruptive impact of severe mood changes. When symptoms are well controlled, many people find it easier to maintain healthy relationships, perform consistently at work or school, and establish routines that support emotional well-being. Better mood stability can also enhance participation in psychotherapy, where individuals develop coping strategies, recognize early warning signs of relapse, and strengthen long-term self-management skills.
Unlike medications that only address active symptoms, lithium is intended to support ongoing stability. Its benefits are usually greatest when taken consistently as prescribed rather than only during periods of worsening symptoms. Regular follow-up appointments allow healthcare providers to assess whether the medication continues to provide meaningful improvement and to adjust the dosage as needed to balance effectiveness and safety.
It is important to remember that lithium does not work the same way for everyone. Some people experience significant symptom control, while others may need a different medication or a combination of treatments to achieve the best results. Treatment decisions are always individualized, taking into account the person’s diagnosis, medical history, treatment response, and preferences.
Key Takeaways
- Lithium is one of the most effective long-term treatments for bipolar disorder.
- It helps reduce the frequency and severity of manic and depressive episodes.
- Research shows lithium is associated with a reduced risk of suicide in people with bipolar disorder.
- The greatest benefits are usually seen when lithium is combined with regular medical monitoring, psychotherapy, and healthy lifestyle habits.
- Treatment plans should always be individualized and reviewed regularly with a qualified healthcare provider.
Side Effects, Risks, and Required Monitoring
Like all prescription medications, lithium can cause side effects and requires ongoing monitoring to help ensure it remains safe and effective. Most side effects are mild and manageable, especially when treatment begins gradually and blood lithium levels stay within the recommended therapeutic range. Regular follow-up appointments allow healthcare providers to identify potential concerns early and make dose adjustments when necessary.
Some of the most common side effects include increased thirst, frequent urination, mild hand tremors, nausea, and weight gain. Some people also notice fatigue or mild stomach discomfort when starting treatment. These effects often improve as the body adjusts to the medication, although persistent or bothersome symptoms should be discussed with the prescribing provider rather than managed independently.
Because lithium is processed by the kidneys, routine laboratory monitoring is an essential part of treatment. Blood tests are performed to measure lithium levels and confirm that the medication remains within its therapeutic range. Healthcare providers also monitor kidney function and thyroid function, as long-term lithium therapy may affect these organs in some individuals. The frequency of testing depends on factors such as treatment duration, dosage changes, overall health, and previous laboratory results. The National Institute of Mental Health (NIMH) Mental Health Medications also explains that people taking lithium should have regular monitoring of lithium levels, kidney function, and thyroid function throughout treatment.
Daily habits can also influence lithium levels. Dehydration, excessive sweating, vomiting, diarrhea, or sudden changes in dietary salt intake can increase the amount of lithium in the bloodstream and raise the risk of toxicity. Patients are generally encouraged to stay well hydrated, maintain a consistent intake of fluids and sodium, and contact their healthcare provider if they become ill or experience significant fluid loss. Certain medications—including some nonsteroidal anti-inflammatory drugs (NSAIDs), diuretics, and ACE inhibitors—can also interact with lithium, making it important to consult a healthcare provider before starting any new prescription or over-the-counter medication.
Although uncommon when lithium is used as prescribed, lithium toxicity is a medical emergency that requires immediate evaluation. Early symptoms may include worsening tremors, severe nausea or vomiting, diarrhea, muscle weakness, poor coordination, slurred speech, confusion, or unusual drowsiness. In more severe cases, toxicity can lead to seizures, loss of consciousness, or life-threatening complications. Anyone experiencing symptoms suggestive of lithium toxicity should seek emergency medical care immediately.
| Common Side Effects | Possible Signs of Lithium Toxicity |
|---|---|
| Mild hand tremor | Severe or worsening tremor |
| Increased thirst | Persistent vomiting or severe diarrhea |
| Frequent urination | Marked muscle weakness |
| Mild nausea | Difficulty walking or loss of coordination |
| Temporary stomach upset | Slurred speech |
| Mild weight gain | Confusion, extreme drowsiness, or seizures |
Most people take lithium safely for many years when they follow their prescribed treatment plan and attend regular monitoring appointments. Rather than viewing blood tests as an inconvenience, they should be seen as an important safety measure that helps healthcare providers maintain an effective dose while reducing the risk of complications. Never adjust your dose, skip monitoring appointments, or stop taking lithium without first speaking with your healthcare provider.
Who May Be a Good Candidate for Lithium?
Lithium may be a good treatment option for people with certain mood disorders, particularly those with bipolar disorder who would benefit from long-term mood stabilization. Healthcare providers consider many factors before prescribing lithium, including the person’s diagnosis, medical history, overall health, and ability to participate in regular monitoring. The goal is to determine whether the expected benefits outweigh the potential risks for each individual.
People with Bipolar I disorder are often considered strong candidates because lithium has consistently demonstrated effectiveness in treating mania and helping prevent future mood episodes. It may also be appropriate for some individuals with Bipolar II disorder, especially when recurring mood episodes significantly affect daily life. In addition, psychiatrists may recommend lithium for selected patients with treatment-resistant depression as an add-on therapy when other evidence-based treatments have not provided sufficient improvement.
Before starting treatment, a healthcare provider will perform a comprehensive evaluation that typically includes a review of current medications, previous psychiatric treatments, medical conditions, and family history. Baseline laboratory tests are usually obtained to assess kidney function, thyroid function, and other health measures that may influence whether lithium is a safe option. These assessments also provide a reference point for future monitoring throughout treatment.
Certain medical conditions require additional caution or may make lithium a less suitable choice. For example, people with significant kidney disease, untreated thyroid disorders, severe dehydration, or conditions that interfere with maintaining stable fluid and sodium balance may require alternative treatments or closer monitoring. Pregnancy or plans to become pregnant should also be discussed with a healthcare provider, as lithium treatment during pregnancy requires careful consideration of both maternal and fetal health.
Successful lithium treatment depends not only on the medication itself but also on a person’s ability to follow the treatment plan. Attending scheduled appointments, completing recommended blood tests, taking the medication consistently, and communicating any new symptoms or medication changes are all essential parts of safe treatment. These ongoing evaluations allow healthcare providers to adjust the dosage when needed and respond promptly to any concerns.
Summary: Key Things to Know Before Starting Lithium
- Lithium is most commonly prescribed for bipolar disorder and selected cases of treatment-resistant depression.
- A thorough medical and psychiatric evaluation is completed before treatment begins.
- Regular blood tests are necessary to monitor lithium levels, kidney function, and thyroid function.
- Staying well hydrated and maintaining consistent dietary habits help support safe treatment.
- Never start, stop, or change your lithium dosage without guidance from your healthcare provider.
When to Talk to a Mental Health Provider About Lithium
You should talk to a mental health provider about lithium if you have symptoms of bipolar disorder, continue to experience depression despite treatment, or have concerns about your current medication plan. Lithium is a prescription medication that requires careful evaluation and ongoing monitoring, so it should only be started, adjusted, or discontinued under the supervision of a qualified healthcare professional.
A psychiatric evaluation can help determine whether lithium is an appropriate treatment based on your symptoms, medical history, previous medication response, and overall health. During this assessment, your provider may discuss your mood patterns, family history of mental health conditions, current medications, and any medical conditions that could affect treatment decisions. This information helps create an individualized care plan that prioritizes both effectiveness and safety.
If you are already taking lithium, contact your healthcare provider if you notice new or worsening side effects, changes in your physical health, or difficulty taking the medication as prescribed. Persistent nausea, increased tremors, excessive thirst, frequent urination, or unexpected changes in weight or energy levels may require further evaluation. Your provider may recommend blood tests or adjust your dosage to help maintain safe and effective treatment.
Certain situations require prompt medical attention because they can increase the risk of lithium toxicity. Seek immediate medical care if you develop severe vomiting, persistent diarrhea, significant dehydration, worsening tremors, muscle weakness, slurred speech, confusion, difficulty walking, seizures, or loss of consciousness while taking lithium. These symptoms should never be ignored, as lithium toxicity can become life-threatening without timely treatment.
Mental health emergencies also require immediate action. If you or someone you know is experiencing suicidal thoughts, has made a suicide attempt, or is in immediate danger of harming themselves or others, call 911, go to the nearest Emergency Department, or contact the 988 Suicide & Crisis Lifeline for immediate support. Lithium is an important treatment for many people, but it is not a substitute for emergency mental health care during a crisis.
Key Takeaways
- Speak with a healthcare provider if you think lithium may be appropriate for your condition or if your current treatment is not adequately controlling your symptoms.
- Never start, stop, or change your lithium dosage without medical guidance.
- Attend all scheduled follow-up appointments and blood tests to help keep treatment safe and effective.
- Seek emergency medical care immediately if you develop symptoms of lithium toxicity.
- Call 911, visit the nearest Emergency Department, or contact the 988 Suicide & Crisis Lifeline if you are experiencing a mental health emergency or suicidal crisis.
Conclusion
Lithium remains one of the most effective and extensively studied medications used in mental health care, particularly for bipolar disorder. It can help control manic episodes, reduce the risk of future mood episodes, and, in selected cases, serve as an add-on treatment for treatment-resistant depression. Its long history of clinical use and evidence supporting long-term mood stabilization continue to make it an important option in psychiatric medication management.
Because lithium has a narrow therapeutic range, successful treatment depends on regular blood tests, routine follow-up appointments, and close communication with a healthcare provider. Taking the medication exactly as prescribed, staying hydrated, and reporting new symptoms promptly all contribute to safer and more effective treatment.
If you think lithium may be appropriate for you or a loved one, speak with a qualified mental health professional. An individualized evaluation can help determine whether lithium fits your diagnosis, overall health, and treatment goals while ensuring that any therapy is both safe and evidence-based.
FAQs
1. What is lithium used for in mental health?
Lithium is primarily used to treat bipolar disorder by helping control manic episodes and preventing future mood episodes. It may also be prescribed alongside antidepressants for some people with treatment-resistant depression.
2. Is lithium only prescribed for bipolar disorder?
No. Although bipolar disorder is its most common use, psychiatrists may also prescribe lithium as an add-on treatment for treatment-resistant depression and, in selected situations, for certain other psychiatric conditions based on clinical judgment.
3. Why do people taking lithium need regular blood tests?
Lithium works within a narrow therapeutic range. Blood tests help ensure the medication remains at a safe and effective level while allowing healthcare providers to monitor kidney and thyroid function.
4. How long does lithium take to work?
For acute mania, improvement may begin within several days, although full effects often develop over one to three weeks. Long-term mood stabilization and benefits for depression may take several weeks to become fully apparent.
5. What are the most common side effects of lithium?
Common side effects include increased thirst, frequent urination, mild hand tremor, nausea, mild stomach upset, fatigue, and weight gain. Many of these improve as the body adjusts, but persistent symptoms should be discussed with a healthcare provider.
6. Can lithium be taken safely for many years?
Yes. Many people use lithium safely for long-term treatment when they follow their prescribed treatment plan, attend regular monitoring appointments, and have periodic blood tests to monitor lithium levels and overall health.
Medical Review Disclosure
Medically Reviewed By: Dr. Gloria Fosu, DNP, PMHNP-BC
Review Date: July 31, 2026
This article is intended for educational purposes only and should not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider regarding questions about medications or your mental health care.
CTA
If you have questions about lithium or other psychiatric medications, the team at Arthur Behavioral Health can help. Our experienced mental health professionals provide comprehensive psychiatric evaluations, personalized medication management, and ongoing support to help you make informed treatment decisions. Contact us to schedule an appointment and discuss the treatment options that best fit your needs.
References
- National Institute of Mental Health (NIMH). Mental Health Medications.
- Substance Abuse and Mental Health Services Administration (SAMHSA). Behavioral Health Treatment Resources.
- American Psychiatric Association. Practice Guideline for the Treatment of Patients With Bipolar Disorder.
- National Institutes of Health (NIH). Lithium in the Treatment of Bipolar Disorder.
- American Society of Health-System Pharmacists. Lithium Drug Information.
- U.S. National Library of Medicine. Lithium – MedlinePlus Drug Information.
