Gabapentin for Restoring GABA/Glutamate Homeostasis in Co-occurring Bipolar and Cannabis Use Disorders

This study tests whether gabapentin (a medication that calms overactive nerve signals) can help people who have both bipolar disorder and cannabis use disorder — two conditions that often occur together and are difficult to treat simultaneously. Researchers believe gabapentin may rebalance brain chemistry disrupted by both conditions. **You may be eligible if...** - You are aged 18–65 and have been diagnosed with both bipolar disorder (type I or II) and moderate-to-severe cannabis use disorder - You use cannabis as your primary substance of concern and had a positive urine test at screening - You are already taking a mood stabilizer (e.g., lithium, valproate, lamotrigine, or an antipsychotic) **You may NOT be eligible if...** - You have another primary psychiatric diagnosis (e.g., schizophrenia) - You have moderate-to-severe use of other substances (other than cannabis or tobacco) in the past 60 days - You have a neurological condition like epilepsy or a history of serious brain injury - You have had ECT (electroconvulsive therapy) in the past 3 months Talk to your doctor to see if this trial is right for you.