Great question — Neurontin (gabapentin) is officially FDA-approved only for seizures and postherpetic neuralgia, but in psychiatry it has been widely prescribed off-label. Here’s a structured overview:
🔹 Off-Label Psychiatric Uses of Gabapentin (Neurontin)
1. Anxiety Disorders
- Generalized Anxiety Disorder (GAD):
- Some small RCTs and case series show anxiolytic effects, but evidence is modest.
- Sometimes used when SSRIs/SNRIs are not tolerated.
- Social Anxiety Disorder (SAD):
- A few small studies suggest benefit, but pregabalin (Lyrica) has far stronger evidence (and is licensed in Europe/Canada for GAD).
- Panic Disorder:
- Some case reports and open trials, but no robust RCT support.
2. Bipolar Disorder
- Studied as an adjunct mood stabilizer in the 1990s.
- Cochrane reviews: no evidence gabapentin is effective for mania, depression, or prophylaxis.
- Sometimes still used when patients cannot tolerate other mood stabilizers, but largely considered ineffective.
3. Alcohol Use Disorder / Alcohol Withdrawal
- Evidence is stronger here compared to other psychiatric uses.
- Gabapentin can reduce alcohol cravings, anxiety, and insomnia in early abstinence.
- Several RCTs (Mason 2014, etc.) show it increases rates of abstinence and reduces relapse.
- Sometimes used for alcohol withdrawal symptoms in outpatient settings (mild–moderate withdrawal), but not a replacement for benzodiazepines in severe withdrawal.
4. Cannabis Use Disorder
- Small RCTs (Mason 2012) suggest gabapentin may reduce cannabis withdrawal symptoms and use.
- Still very preliminary and not guideline-endorsed.
5. Other Psychiatric Uses
- PTSD: Some anecdotal and open trials for nightmares, insomnia, hyperarousal; data weak.
- Insomnia: Occasionally used off-label for sleep initiation and maintenance, especially in comorbid anxiety or substance use.
- Impulsivity/Aggression: Rarely trialed in borderline personality disorder or agitation; evidence minimal.
⚠️ Key Considerations
- Evidence strength: Only alcohol use disorder/withdrawal has replicated, moderate-quality evidence. Anxiety uses are weak-to-moderate. For bipolar/PTSD/insomnia, evidence is weak.
- Misuse potential: Gabapentin is increasingly recognized to have abuse/diversion potential, especially in patients with opioid use disorder. Some U.S. states have reclassified it as a controlled substance.
- Side effects: Sedation, dizziness, ataxia, cognitive blunting. Generally well tolerated but not free of risks.
✅ Summary
- Most supported off-label psychiatric uses:
- Alcohol use disorder / withdrawal
- Anxiety (esp. GAD, social anxiety) when first-line options fail
- Weak/limited evidence: PTSD, insomnia, cannabis use disorder, mood stabilization in bipolar disorder.
- Not recommended: As a core mood stabilizer in bipolar (negative trials).
👉 Would you like me to make you a comparison chart of gabapentin vs pregabalin (Lyrica) for these off-label psychiatric uses, since they’re often considered side by side in anxiety and substance use?
