Using Gabapentin to Help People with Bipolar Disorder and Cannabis Use Issues

Gabapentin for Restoring GABA/Glutamate Homeostasis in Co-occurring Bipolar and Cannabis Use Disorders: A Randomized, Double-blind, Placebo-controlled, Parallel-group, MRI Study

Phase 2 Interventional Medical University of South Carolina · NCT05064319

This study is testing if Gabapentin can help adults with Bipolar Disorder and cannabis use issues feel better by balancing certain chemicals in their brain.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment68 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorMedical University of South Carolina Academic / other
Locations1 site (Charleston, South Carolina)
Trial IDNCT05064319 on ClinicalTrials.gov

What this trial studies

This research evaluates the effects of Gabapentin, an FDA-approved medication, on individuals aged 18-65 who have both Bipolar Disorder and moderate to severe cannabis use disorder. Participants will be randomly assigned to receive either Gabapentin or a placebo for 17 days, with five study visits that include MRI brain scans and assessments of side effects. The study aims to understand how Gabapentin can help restore the balance of GABA and glutamate in the brain for these patients.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18-65 with a diagnosis of Bipolar Disorder and moderate to severe cannabis use disorder.

Not a fit: Patients with primary psychiatric diagnoses other than Bipolar Disorder or those with uncontrolled neurological conditions may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could improve mood stability and reduce cannabis use in patients with co-occurring disorders.

How similar studies have performed: While this approach is novel in targeting the specific combination of Bipolar Disorder and cannabis use, similar studies have shown promise in using Gabapentin for other conditions.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Ages 18-65 years
2. Meet DSM-5 criteria for moderate or severe cannabis use disorder (CUD; within the past 3 months), provide a positive urine cannabinoid screen at baseline, and identify cannabis as the primary substance of abuse
3. Meet DSM-5 criteria for bipolar I or II disorder (BD) or Schizoaffective Disorder, Bipolar Type
4. Able to provide informed consent and read, understand, and accurately complete assessment instruments
5. Willing to commit to medication treatment and follow-up assessments
6. Prescribed daily use of at least one mood stabilizing medication (i.e., lithium, divalproex sodium, lamotrigine, carbamazepine, 2nd generation antipsychotic)

Exclusion Criteria:

1. A primary psychiatric diagnosis other than BD (e.g., Schizophrenia)
2. Meet DSM-5 criteria for moderate or severe substance use disorder (other than cannabis or tobacco) within the past 60 days
3. Any uncontrolled neurological condition (e.g., epilepsy) that could confound the results of the study
4. Any history of brain injury with loss of consciousness greater than 5 minutes
5. Any history of mental retardation, dementia, or recent electroconvulsive therapy (in the past 3 months)
6. Any uncontrolled medical condition that may adversely affect the conduct of the study or jeopardize the safety of the participant
7. Hepatocellular disease as indicated by plasma levels of liver transaminases (aspartate transaminase, alanine transaminase) greater than 3 times the normal range
8. Renal insufficiency as indicated by plasma levels of creatinine greater than 2 times the normal range
9. Concomitant use of medications that could interfere with glutamatergic/GABAergic transmission (e.g., benzodiazepines, ceftriaxone, riluzole, memantine, ketamine, topiramate, vigabatrin), due to potential confounding effects
10. Concomitant use of opioid medications, benzodiazepines, barbiturates, chloral hydrate, sodium oxybate, or any other medication deemed to be hazardous if taken with gabapentin
11. Azelastine, orphenadrine, oxomemazine, paraldehyde, and thalidomide are generally contraindicated in patients taking gabapentin; as such, individuals taking these medications will be excluded
12. Women of childbearing potential who are pregnant, lactating, or refuse adequate forms of contraception
13. Current suicidal or homicidal risk
14. Baseline scores greater than 35 on the Montgomery-Asberg Depression Rating Scale or greater than 25 on the Young Mania Rating Scale
15. Has taken gabapentin in the last month or experienced adverse effects/allergic reaction (e.g., angioedema) from it at any time
16. Significant claustrophobia and/or past negative experiences with MRI
17. Presence of non-MRI safe materials in the body (e.g., ferrous metal implants, pacemaker)

Where this trial is running

Charleston, South Carolina

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Bipolar DisorderCannabis UseSchizoaffective Disorder, Bipolar TypeBipolar I DisorderBipolar II DisorderCannabis Use Disorder, MildCannabis Use Disorder, ModerateCannabis Use Disorder, Severe
Last reviewed 2026-06-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.