What are the psychiatric indications for gabapentin?

Psychiatric Indications for Gabapentin

Gabapentin has no FDA-approved psychiatric indications, but it is commonly used off-label for anxiety disorders, particularly preoperative anxiety, and as an adjunctive treatment for alcohol withdrawal syndrome. The evidence for its use in other psychiatric conditions is limited and often inconclusive.

Evidence-Based Psychiatric Applications

Anxiety Disorders

• Strongest evidence: Gabapentin shows moderate efficacy for various forms of anxiety disorders 1
  • Particularly effective for preoperative anxiety (SMD -0.92,95% CI -1.32 to -0.52) 1
  • Beneficial in social phobia and anxiety in specific populations (e.g., breast cancer survivors) 2
  • Typical dosing: >1200 mg/day in divided doses 3

Substance Use Disorders

• Alcohol use disorder:
  • Effective for acute alcohol withdrawal syndrome of mild to moderate severity 2
  • Reduces cravings, improves abstinence rates, and delays return to heavy drinking 2
  • May be considered as part of a comprehensive treatment approach

Limited or Inconclusive Evidence

• Bipolar disorder:

  • Minimal evidence supporting efficacy 1
  • Controlled studies in adults have not found gabapentin to be helpful for bipolar disorder 4
  • Not recommended as a first-line or monotherapy option

• Depression: No clear evidence supporting its use 5

• PTSD: Insufficient evidence to support routine use 5, 2

• OCD: No significant benefit observed 2

• Other substance use disorders:

  • Limited evidence for opioid dependence and cannabis dependence 2
  • No significant benefit for cocaine or amphetamine abuse 2

Prescribing Considerations

Dosing

• Starting dose: 300 mg once daily 3
• Therapeutic dose range: >1200 mg/day in divided doses for anxiety and neuropathic pain 3
• Titration: Slower than pregabalin, typically over weeks 3

Adverse Effects

• Common side effects include:
  • Somnolence/sedation (19% vs 9% placebo) 6
  • Dizziness (17% vs 7% placebo) 6
  • Ataxia (13% vs 6% placebo) 6
• Risk of suicidal thoughts or behavior (similar to other antiepileptic drugs) 6
• Neuropsychiatric reactions in pediatric patients (emotional lability, hostility, thought disorder, hyperkinesia) 6

Special Precautions

• Monitor for emergence or worsening of depression, suicidal thoughts or behavior 6
• Use with caution when combined with other CNS depressants (58.4% of off-label gabapentin prescriptions include concomitant CNS depressant medications) 7
• Dose adjustment required in renal impairment 3

Clinical Perspective

Despite widespread off-label use in psychiatric practice (5.3% for depressive disorders, 3.5% for anxiety disorders, and 1.8% for bipolar disorder) 7, the evidence base for gabapentin in psychiatric conditions remains limited. The strongest evidence supports its use in anxiety disorders and alcohol withdrawal/dependence.

When considering gabapentin for psychiatric indications, clinicians should:

1. Recognize it is not FDA-approved for psychiatric conditions
2. Consider it primarily for anxiety disorders where evidence is strongest
3. Use it as an adjunctive rather than monotherapy for most conditions
4. Be aware of the potential for misuse, particularly in patients with substance use disorders
5. Monitor for neuropsychiatric adverse effects, especially in combination with other CNS depressants