NCT05064319 · Medical University of South Carolina
Gabapentin for Restoring GABA/Glutamate Homeostasis in Co-occurring Bipolar and Cannabis Use Disorders
What this study is about
This research study evaluates the effects of an FDA-approved medication Gabapentin in individuals with Bipolar Disorder who smoke marijuana. Participants in the study will will be assigned to take either Gabapentin or a matched placebo. Study medication will be taken for 17 days. There will be 5 study visits, with 2 MRI brain imaging scans completed.
View original scientific description
This research study evaluates the effects of an FDA-approved medication Gabapentin in individuals with Bipolar Disorder who smoke marijuana. Participants in the study will will be assigned to take either Gabapentin or a matched placebo. Study medication will be taken for 17 days. There will be 5 study visits, with 2 MRI brain imaging scans completed. Questionnaires and clinical interview measures will be completed at study visits along with consistent assessment of potential side effects from study medication.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Ages 18-65 years
- 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
- Meet DSM-5 criteria for bipolar I or II disorder (BD) or Schizoaffective Disorder, Bipolar Type
- Able to provide informed consent and read, understand, and accurately complete assessment instruments
- Willing to commit to medication treatment and follow-up assessments
- Prescribed daily use of at least one mood stabilizing medication (i.e., lithium, divalproex sodium, lamotrigine, carbamazepine, 2nd generation antipsychotic)
Exclusion criteria
- A primary psychiatric diagnosis other than BD (e.g., Schizophrenia)
- Meet DSM-5 criteria for moderate or severe substance use disorder (other than cannabis or tobacco) within the past 60 days
- Any uncontrolled neurological condition (e.g., epilepsy) that could confound the results of the study
- Any history of brain injury with loss of consciousness greater than 5 minutes
- Any history of mental retardation, dementia, or recent electroconvulsive therapy (in the past 3 months)
- Any uncontrolled medical condition that may adversely affect the conduct of the study or jeopardize the safety of the participant
- Hepatocellular disease as indicated by plasma levels of liver transaminases (aspartate transaminase, alanine transaminase) greater than 3 times the normal range
- Renal insufficiency as indicated by plasma levels of creatinine greater than 2 times the normal range
- 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
- Concomitant use of opioid medications, benzodiazepines, barbiturates, chloral hydrate, sodium oxybate, or any other medication deemed to be hazardous if taken with gabapentin
- Azelastine, orphenadrine, oxomemazine, paraldehyde, and thalidomide are generally contraindicated in patients taking gabapentin; as such, individuals taking these medications will be excluded
- Women of childbearing potential who are pregnant, lactating, or refuse adequate forms of contraception
- Current suicidal or homicidal risk
- Baseline scores greater than 35 on the Montgomery-Asberg Depression Rating Scale or greater than 25 on the Young Mania Rating Scale
- Has taken gabapentin in the last month or experienced adverse effects/allergic reaction (e.g., angioedema) from it at any time
- Significant claustrophobia and/or past negative experiences with MRI
- Presence of non-MRI safe materials in the body (e.g., ferrous metal implants, pacemaker)
Where
- Charleston, South Carolina
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 8, 2025 · Source of record for eligibility and locations