Gabapentin is not a mood stabilizer. It is an anticonvulsant medication approved by the FDA for two specific conditions: nerve pain after shingles (postherpetic neuralgia) and as an add-on treatment for partial seizures in people with epilepsy. It has no FDA approval for bipolar disorder, and clinical trials have not demonstrated that it effectively stabilizes mood.
Despite this, gabapentin is widely prescribed off-label for psychiatric symptoms, and roughly 83% of all gabapentin prescriptions are for conditions it was never approved to treat. That gap between the evidence and real-world prescribing is worth understanding if you or someone you know takes gabapentin for mood-related reasons.
What Clinical Trials Actually Show
The most direct test of gabapentin as a mood stabilizer came from a placebo-controlled trial in outpatients with bipolar disorder. The results were discouraging. Patients who received a placebo actually had a greater reduction in mania scores than those who received gabapentin. The placebo group’s mania scores dropped by 9 points, compared to just 6 points in the gabapentin group, a statistically significant difference favoring the sugar pill. For depression scores, there was no meaningful difference between gabapentin and placebo.
A broader review of double-blind controlled studies comparing anticonvulsants in bipolar disorder reached a similar conclusion: gabapentin has not been found effective for any phase of bipolar illness. Valproate has solid evidence for acute mania. Lamotrigine has proven efficacy in bipolar depression. Gabapentin has neither. The review reaffirmed that lithium remains the gold-standard treatment for preventing bipolar episodes, with carbamazepine and valproate as established alternatives.
A 2022 systematic review and meta-analysis published in Molecular Psychiatry looked specifically at gabapentin and its close relative pregabalin in bipolar disorder, anxiety, and insomnia. It found no evidence that gabapentin works as an adjunctive treatment in bipolar disorder. There were no significant differences between gabapentin and placebo on mania scores, depression scores, anxiety scores, or time to recurrence of new mood episodes.
Why Psychiatrists Still Prescribe It
If the trial data are this underwhelming, why does gabapentin keep showing up in psychiatric prescriptions? The answer lies in a combination of clinical pragmatism and the complexity of mood disorders. In interviews with psychiatrists about their off-label gabapentin use, several reported finding it “clinically meaningful” for managing anxiety, insomnia, and certain mood symptoms in their patients. Two psychiatrists noted they use it as a last resort after approved treatments have been exhausted.
This pattern makes more sense when you consider what gabapentin does in the brain. It binds to a specific subunit of voltage-gated calcium channels, which reduces the release of excitatory neurotransmitters. This calming effect on overactive nerve signaling may help with anxiety and sleep disturbances, two symptoms that frequently accompany bipolar disorder and other mood conditions. So while gabapentin doesn’t treat the core mood cycling of bipolar disorder, it might ease some of the surrounding symptoms that make daily life harder.
The CANMAT/ISBD 2018 guidelines for bipolar disorder, one of the most widely referenced treatment frameworks in psychiatry, explicitly list gabapentin as “not recommended” for acute mania based on negative evidence. However, the same guidelines place adjunctive gabapentin as a third-line option for long-term maintenance treatment, meaning it might be considered for patients who haven’t responded adequately to first- or second-line therapies. That’s a narrow, last-resort role, not a primary treatment.
How Gabapentin Differs From True Mood Stabilizers
A true mood stabilizer does something specific: it reduces the frequency and severity of both manic and depressive episodes over time. Lithium, the benchmark, does this reliably and has decades of evidence behind it. Valproate can control acute mania and prevent switches into depression. Lamotrigine protects against depressive episodes. Each of these has demonstrated, in rigorous trials, the ability to alter the course of bipolar disorder.
Gabapentin has not cleared that bar. It doesn’t reduce mania better than placebo. It doesn’t prevent new mood episodes. It doesn’t improve depression scores in bipolar patients. Calling it a mood stabilizer based on available evidence would be inaccurate, even though it belongs to the same anticonvulsant drug class as some medications that do stabilize mood. Being an anticonvulsant doesn’t automatically make a drug a mood stabilizer. Each compound works differently in the brain, and the overlap between seizure control and mood regulation is inconsistent across the class.
Risks Worth Knowing About
Gabapentin is often perceived as a relatively mild medication, but it carries real risks, particularly for certain groups. People with a history of substance use disorders face the highest risk of gabapentin misuse. When gabapentin is combined with opioids, the danger increases substantially. One study found that sustained gabapentin use above 3,600 mg per day combined with opioids quadrupled the odds of hospitalization, including for altered mental status.
Withdrawal is another consideration. If you stop gabapentin abruptly after regular use, withdrawal symptoms typically begin within 24 to 48 hours. These can include agitation, confusion, sweating, tremor, rapid heart rate, high blood pressure, stomach upset, and insomnia. Tapering off gradually under medical guidance is the standard approach to avoid these effects.
Like all anticonvulsants, gabapentin also carries an FDA warning about increased risk of suicidal thoughts and behavior, something particularly relevant for anyone taking it for a psychiatric condition.
What This Means for You
If you’re taking gabapentin and it seems to help with anxiety, sleep, or general emotional steadiness, that doesn’t necessarily mean it’s stabilizing your mood in the clinical sense. It may be addressing peripheral symptoms like restlessness or insomnia that make mood episodes feel worse. That can be genuinely valuable, but it’s different from treating the underlying condition.
If you’ve been prescribed gabapentin as part of a broader treatment plan that includes a proven mood stabilizer, it may be playing a supporting role your prescriber finds useful for your specific symptom profile. If gabapentin is the only medication you’re taking for bipolar or mood-related symptoms, the evidence suggests it’s unlikely to provide adequate control on its own. Effective mood stabilization typically requires medications with stronger evidence behind them, such as lithium, valproate, lamotrigine, or certain atypical antipsychotics.