Lithium remains the oldest and most thoroughly studied medication for bipolar disorder, with decades of evidence showing it prevents both manic and depressive episodes and reduces the risk of suicide in ways that no other mood stabilizer has consistently matched. First introduced to psychiatry in 1949 by the Australian physician John Cade, it took until 1970 for the United States to approve it, making the country the 50th to do so.1PubMed Central. The history of lithium therapy Despite newer medications entering the market, lithium’s combination of mood-stabilizing, anti-suicidal, and neuroprotective properties keeps it at the center of bipolar treatment, though its narrow safety margin and long-term side effects mean it demands closer attention than most psychiatric drugs.
How Well It Prevents Episodes
The core reason lithium is prescribed long-term is maintenance: keeping people with bipolar disorder from cycling back into mania or depression. A Cochrane systematic review concluded that lithium is an efficacious maintenance treatment for bipolar disorder, with a consistent advantage over placebo in preventing relapse.2PubMed Central. Lithium for maintenance treatment of mood disorders A separate meta-analysis of seven trials and over 1,500 participants put numbers to that effect: lithium roughly cut the rate of manic episodes in half compared to placebo and reduced overall mood episodes by about a third.3PubMed Central. Lithium for prevention of mood episodes in bipolar disorders: systematic review and meta-analysis
The story on depression is a bit more qualified. That same meta-analysis found lithium’s ability to prevent depressive episodes depended on the statistical method used: the effect was clear in one type of analysis and fell just short of conventional significance in another.4PubMed Central. Lithium for prevention of mood episodes in bipolar disorders: systematic review and meta-analysis In practice, clinicians generally regard lithium as stronger at preventing mania than depression, which sometimes leads to adding a second medication for the depressive side of the illness.
The Suicide Prevention Effect
Lithium’s most striking benefit may be its ability to lower suicide risk, and this appears to go beyond what you’d expect from simply stabilizing mood. A large meta-analysis published in the BMJ found that people taking lithium were far less likely to die by suicide than those on placebo, with an even broader reduction in death from any cause.5BMJ. Lithium in the prevention of suicide in mood disorders: updated systematic review and meta-analysis A nationwide registry study from Denmark echoed that pattern, finding lithium was linked to roughly a 60-70% lower risk of suicide death, along with a nearly 50% reduction in death from all causes.6PubMed. Lithium is associated with decrease in all-cause and suicide mortality in high-risk bipolar patients: A nationwide registry-based prospective cohort study
What makes this especially interesting is that the anti-suicidal effect seems to operate at least partly independently of mood stabilization. Evidence suggests lithium can reduce suicidal behavior even when someone’s mood isn’t fully under control and even at blood levels lower than what’s typically considered therapeutic for bipolar symptoms.7PubMed Central. Lithium Suicide Prevention: A Brief Review and Reminder The mechanism behind this is not fully understood, but researchers suspect lithium’s effects on impulsivity and aggression play a role. This anti-suicidal property is one reason clinicians sometimes favor lithium over other mood stabilizers, particularly for patients at higher risk.
What Lithium Does in the Brain
After more than 70 years of clinical use, lithium’s exact mechanism still isn’t fully nailed down, which is unusual for such a widely prescribed drug. The two pathways that get the most attention involve enzymes called glycogen synthase kinase 3 (GSK-3) and inositol monophosphatase. Lithium inhibits both by displacing magnesium, a metal that normally helps these enzymes function.8PubMed Central. Lithium: the pharmacodynamic actions of the amazing ion Blocking GSK-3 influences a cascade of processes in neurons, from how cells grow and survive to how they respond to stress. One proposed model suggests that inositol depletion and GSK-3 inhibition are actually interconnected rather than separate mechanisms.9PubMed Central. Inositol depletion, GSK3 inhibition and bipolar disorder
Lithium also has clear neuroprotective properties. Animal studies show it boosts levels of brain-derived neurotrophic factor (BDNF), a protein that supports neuron survival and growth, while simultaneously turning down signals that push neurons toward cell death.10PubMed Central. Lithium-induced neuroprotection is associated with epigenetic modification of specific BDNF gene promoter and altered expression of apoptotic-regulatory proteins In rat brain cells, lithium increased both the length and number of neuronal branches and protected cells against toxic damage.11PubMed Central. Neuroprotective action of lithium in disorders of the central nervous system Whether these lab findings fully explain how lithium stabilizes mood in humans is still an open question, but they help explain why the drug has attracted interest beyond bipolar disorder.
The Narrow Therapeutic Window
Lithium’s most demanding feature is its narrow therapeutic window: the gap between a dose that works and a dose that becomes dangerous is small. Too little lithium in the blood and it won’t do much; too much and you risk serious toxicity.12Neuroscience Applied. Lithium treatment for affective disorders: Exploring the potential of salivary therapeutic monitoring This is why people on lithium need regular blood draws to check their levels, typically every few months once stable, and more frequently when starting or adjusting the dose.13PubMed. Lithium: updated human knowledge using an evidence-based approach. Part II: Clinical pharmacology and therapeutic monitoring
Several everyday factors can push lithium levels up unexpectedly. Dehydration is a common culprit, because lithium is excreted through the kidneys in tandem with sodium and water. A hot day, a stomach flu, a new diuretic medication, or simply not drinking enough fluids can all concentrate lithium in the blood. Nonsteroidal anti-inflammatory drugs like ibuprofen also reduce lithium clearance. These interactions make lithium a medication that requires a certain amount of patient vigilance: you need to know what can throw your levels off.
When levels climb too high, early symptoms include tremor, nausea, and diarrhea. At more toxic levels, neurological symptoms dominate: confusion, slurred speech, and unsteadiness. In severe cases, a condition called SILENT (Syndrome of Irreversible Lithium-Effectuated Neurotoxicity) can develop, where neurological damage persists even after lithium is cleared from the body. A review of SILENT cases found that altered consciousness was the most common acute symptom, appearing in about 60% of cases, and lasting cerebellar damage (affecting coordination and balance) was the most common persistent problem, mentioned in 77% of reports.14PubMed Central. The Syndrome of Irreversible Lithium-Effectuated Neurotoxicity: A Scoping Review Irreversible neurotoxicity is rare and usually associated with prolonged toxic exposure, but it underscores why monitoring matters.
Side Effects Over the Long Term
Even at therapeutic levels, lithium takes a toll on certain organs over years of use. The kidneys and thyroid bear the biggest burden.
A large retrospective study found that lithium use was associated with roughly double the risk of developing stage three chronic kidney disease compared to matched patients not on lithium, along with a more-than-doubled risk of hypothyroidism.15The Lancet. Long-term and in-parallel analysis of renal, endocrine, and metabolic outcomes in patients given lithium therapy: a retrospective cohort study A study following patients who had taken lithium for 10 to 29 years found that about a third showed signs of chronic kidney problems, though only about 5% had reached a severe or very severe stage.16PubMed. Effects of 10 to 30 years of lithium treatment on kidney function The risk factors compound: older age, longer duration on lithium, and conditions like high blood pressure or diabetes all raise the probability of kidney decline.17PubMed Central. Key questions on the long term renal effects of lithium: a review of pertinent data
Excessive thirst and urination, a condition called nephrogenic diabetes insipidus, is a separate kidney issue that may affect up to 40% of people on lithium.18Medsafe. Renal dangers associated with long term lithium use This happens because lithium interferes with the kidney’s ability to concentrate urine, causing the body to flush more water than it should. Duration on lithium appears to be the strongest predictor of this problem.19PubMed Central. Key questions on the long term renal effects of lithium: a review of pertinent data
Beyond the kidneys, lithium has been linked to elevated calcium levels and hyperparathyroidism.20PubMed Central. Lithium-Induced Hyperparathyroidism: An Ill-defined Territory A cohort study of over 6,600 patients with bipolar disorder confirmed increased rates of renal, thyroid, and parathyroid problems among lithium users, but also noted that the absolute number of severe outcomes was low.21PubMed. Association between lithium treatment and renal, thyroid and parathyroid function: A cohort study of 6659 patients with bipolar disorder This is the essential tension of lithium treatment: the risks are real and cumulative, but for many patients the benefits in episode prevention and suicide reduction outweigh them, particularly with regular monitoring.
Why People Stop Taking It
A retrospective study of 873 patients found that more than half discontinued lithium at some point. In about 62% of those episodes, side effects were the reason. The most common complaints driving discontinuation were diarrhea, tremor, excessive thirst and urination, rising creatinine levels (a sign of kidney stress), and weight gain.22BMC Psychiatry. Reasons for lithium discontinuation in men and women with bipolar disorder: a retrospective cohort study These are the side effects that grind people down day to day: not dramatic emergencies, but quality-of-life problems that accumulate until people decide they’d rather take their chances without the drug.
Stopping lithium, however, carries its own serious risk. The most well-documented danger is an early and sharper-than-expected return of bipolar episodes, particularly mania. Research shows that the risk of manic relapse in the first weeks after stopping lithium is actually higher than what you’d predict from the natural pattern of the illness itself, and relapses can occur even if lithium is interrupted for just a few days.23PubMed. Short-term sequelae of lithium discontinuation Abrupt discontinuation is riskier than a gradual taper. For this reason, clinicians strongly advise against stopping lithium suddenly without medical guidance, and patients who want to discontinue are typically tapered slowly over weeks to months.
How Lithium Compares to Other Options
Valproate (commonly known by brand names like Depakote) is lithium’s most direct competitor as a mood stabilizer. Head-to-head, both work against acute mania, with lithium showing a slight edge overall in early trials.24PubMed. A double-blind comparison of valproate and lithium in the treatment of acute mania Where they differ more clearly is in long-term prevention: lithium’s strength is maintenance, while valproate may be more effective as an acute anti-manic agent than as a prophylactic one.25PubMed Central. Lithium and Valproate in Bipolar Disorder: From International Evidence-based Guidelines to Clinical Predictors Second-generation antipsychotics like quetiapine, olanzapine, and aripiprazole have also become mainstream in bipolar treatment and are recognized as useful across all phases of the illness.26PubMed Central. At 75 Years, Is Lithium the Gold Standard in Bipolar Disorder?
When lithium or valproate alone doesn’t fully control mania, adding an atypical antipsychotic can help. A study of patients who hadn’t fully responded to lithium or valproate alone found that adding olanzapine improved mania scores significantly more than continuing on the mood stabilizer by itself, with about two-thirds of the combination group responding compared to under half on monotherapy.27JAMA Psychiatry. Efficacy of Olanzapine in Combination With Valproate or Lithium in the Treatment of Mania in Patients Partially Nonresponsive to Valproate or Lithium Monotherapy A broader review of add-on therapies found that most combinations tested alongside lithium showed positive effects on treatment outcomes.28PubMed Central. Lithium, the gold standard drug for bipolar disorder: analysis of current clinical studies
Pregnancy and Children
Lithium in pregnancy has been a concern since the 1970s, when early reports linked it to Ebstein’s anomaly, a rare heart defect. Modern data paints a more nuanced picture. A large study published in the New England Journal of Medicine found that lithium exposure during the first trimester was associated with a modestly elevated risk of cardiac malformations overall, with a more specific increase in defects involving the right side of the heart’s outflow tract.29PubMed Central. Lithium Use in Pregnancy and the Risk of Cardiac Malformations The absolute risk remains low, but the finding is enough that clinicians and patients usually weigh it carefully. For some women with severe bipolar disorder, the risk of untreated mood episodes during pregnancy may be more dangerous than the small increase in cardiac malformation risk, making this a genuinely difficult decision that depends on individual circumstances.
In children and adolescents, lithium is FDA-approved for bipolar disorder in those aged 7 and older, and accumulating evidence supports its use. A systematic review of randomized trials found lithium was better than placebo at treating manic and mixed episodes in young patients, though it appeared less effective than antipsychotics in that setting.30PubMed Central. Use of Lithium in Pediatric Bipolar Disorders and Externalizing Childhood-related Disorders: A Systematic Review of Randomized Controlled Trials A placebo-controlled discontinuation study in adolescents showed that those who stayed on lithium had a significantly lower risk of relapse than those switched to placebo, with most adverse events being mild to moderate.31PubMed Central. Lithium for the Maintenance Treatment of Bipolar I Disorder: A Double-Blind, Placebo-Controlled Discontinuation Study The side effect profile in younger patients appears similar to what’s seen in adults, and newer dosing approaches have improved tolerability.32PubMed. Using Lithium in Children and Adolescents with Bipolar Disorder: Efficacy, Tolerability, and Practical Considerations
Predicting Who Will Respond Best
Not everyone with bipolar disorder responds equally well to lithium. Research has identified a profile of patients most likely to benefit: those with a classic pattern of distinct manic and depressive episodes (rather than rapid cycling or mixed states), a family history of mood disorders, and a temperament that leans toward the “up” side between episodes. Patients with certain personality features and a lack of cognitive disorganization also tend to do better on lithium prophylaxis.33PubMed Central. Response to lithium in bipolar disorder: clinical and genetic findings
The genetics of lithium response are an active area of research. Family studies strongly suggest that the tendency to respond to lithium runs in families.34PubMed. Lithium response in bipolar disorder: Genetics, genomics, and beyond A genome-wide association study identified a specific region on chromosome 21 that was linked to lithium response, and in a follow-up group of patients treated with lithium alone, carriers of the response-associated genetic variants had a significantly lower relapse rate over two years of treatment.35The Lancet. Genome-wide association study of response to lithium therapy in bipolar disorder This is still early-stage work; no genetic test can yet reliably predict whether lithium will work for a given individual, but the research points toward a future where the choice of mood stabilizer could be guided by a person’s genetic profile rather than months of trial and error.
Lithium in Drinking Water and Suicide Rates
One of the more surprising lines of research involves naturally occurring lithium in drinking water. Lithium exists as a trace element in groundwater at levels far below anything used in psychiatric treatment. A systematic review and meta-analysis of ecological studies found a consistent inverse association between lithium concentrations in public water supplies and suicide rates at the population level: regions with higher natural lithium levels tended to have lower suicide rates.36PubMed. Association between naturally occurring lithium in drinking water and suicide rates: systematic review and meta-analysis of ecological studies Studies from multiple countries, including Austria, have replicated the finding that higher natural lithium levels are associated with decreased suicide risk.37PubMed Central. Lithium in drinking water and suicide mortality: interplay with lithium prescriptions
This does not mean anyone is proposing to add therapeutic-dose lithium to drinking water. The concentrations in groundwater are thousands of times lower than what’s prescribed for bipolar disorder. But the ecological data are consistent enough that some researchers have floated the idea of trace-level lithium supplementation of water supplies, similar to fluoride for dental health. The idea remains speculative and controversial, partly because ecological studies can’t prove causation and partly because even trace lithium supplementation at scale would raise significant ethical questions.
Emerging Uses Beyond Mood Stabilization
Lithium’s neuroprotective properties have attracted interest from researchers studying neurodegenerative diseases. Based on its ability to inhibit GSK-3 and promote brain cell survival, lithium has been explored as a potential treatment for Alzheimer’s disease, amyotrophic lateral sclerosis (ALS), and Parkinson’s disease.38PubMed Central. Neuroprotective effects of lithium: implications for the treatment of Alzheimer’s disease and related neurodegenerative disorders Early research in ALS patients suggested lithium could slow disease progression, a finding researchers attributed in part to lithium’s ability to activate autophagy, the cellular housekeeping process that clears damaged proteins.39PubMed. Autophagy and amyotrophic lateral sclerosis: The multiple roles of lithium Subsequent larger trials in ALS have been disappointing, and lithium is not currently an established treatment for any neurodegenerative condition. Still, the underlying biology keeps it in the conversation as a candidate worth investigating, and observational data hinting at lower rates of dementia among long-term lithium users continue to generate interest in the Alzheimer’s field.