Bipolar DisorderPhase 2NCT05064319
Gabapentin for Restoring GABA/Glutamate Homeostasis in Co-occurring Bipolar and Cannabis Use Disorders
A Phase 2 study testing Gabapentin in people with Bipolar Disorder and Cannabis Use, run by Medical University of South Carolina at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Bipolar Disorder, Cannabis Use, Schizoaffective Disorder, Bipolar Type
- What is being tested?
- Gabapentin
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 51 participants
- Where
- 1 siteUnited States
- Study dates
- 24 Feb 2022to 31 Jul 2026
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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)
Who cannot join
- 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
Show all 17Show fewer
- 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)
Trial locations and contacts
1 site in 1 country.
United States1 site
Medical University Of South Carolina
Charleston, South Carolina, 29425
About this study
Official title: Gabapentin for Restoring GABA/Glutamate Homeostasis in Co-occurring Bipolar and Cannabis Use Disorders: A Randomized, Double-blind, Placebo-controlled, Parallel-group, MRI Study
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.
- Conditions
- Bipolar Disorder, Cannabis Use, Schizoaffective Disorder, Bipolar Type, Bipolar I Disorder, Bipolar II Disorder, Cannabis Use Disorder, Mild
- Being tested
- Gabapentin, Placebo
- Medical subject headings
- Bipolar Disorder, Psychotic Disorders, Lymphoma, Follicular
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
GabapentinDrug
After group assignment but before taking any study medication, and again 17 days later, participants will have a Magnetic Resonance Imaging (MRI) exam after completing various assessments (clinical interview, questionnaires, etc.). Group A will receive gabapentin 2-3 times a day for a total of 17 days.
PlaceboDrug
After group assignment but before taking any study medication, and again 17 days later, participants will have a Magnetic Resonance Imaging (MRI) exam after completing various assessments (clinical interview, questionnaires, etc.). Group A will receive placebo 2-3 times a day for a total of 17 days.
| Study group | Role | What they receive |
|---|---|---|
| Group A - Gabapentin | Experimental | Not described Receives: Drug: Gabapentin |
| Group B - Placebo | Placebo comparator | Not described Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in prefrontal GABA concentrations through Proton Magnetic Resonance Spectroscopy
Concentrations of GABA, normalized to water and corrected for CSF%, in dorsal anterior cingulate measured via Proton Magnetic Resonance Spectroscopy.
Measured: Baseline to end of treatment, approximately 17 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Oct 2021
- Study start24 Feb 2022
- Primary completion31 Jul 2026
- Study completion31 Jul 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Bipolar DisorderStudies of the same condition, open and under way.
- More trials run by Medical University of South CarolinaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 51 participants (actual)
Sponsor and investigators
- Lead sponsor
- Medical University of South Carolina
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Responsible party
- Principal investigator, James Prisciandaro, Medical University of South Carolina
- Investigators
- James J Prisciandaro, PhD, Principal investigator, Medical University of South Carolina
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05064319
- Sponsor's protocol ID
- 00112593
- Other IDs
- R01DA054275
- Status last verified
- Aug 2026
- First submitted
- 22 Sep 2021
- Last updated
- 9 Sep 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 9 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Gabapentin for Restoring GABA/Glutamate Homeostasis in Co-occurring Bipolar and Cannabis Use Disorders: A Randomized, Double-blind, Placebo-controlled, Parallel-group, MRI Study
- ClinicalTrials.gov ID
- NCT05064319
- Acronym / sponsor ID
- 00112593
- Conditions
- Bipolar Disorder, Cannabis Use, Schizoaffective Disorder, Bipolar Type, Bipolar I Disorder, Bipolar II Disorder, Cannabis Use Disorder, Mild
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 51 participants (actual)
- Lead sponsor
- Medical University of South CarolinaUniversity, hospital or other
- Collaborators
- National Institute on Drug Abuse (NIDA)
- Study start
- 24 Feb 2022 (actual)
- Primary completion
- 31 Jul 2026 (actual)
- Study completion
- 31 Jul 2026 (actual)
- First posted
- 1 Oct 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Group A - Gabapentin | Experimental | Drug: Gabapentin |
| Group B - Placebo | Placebo comparator | Drug: Placebo |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- 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
Key exclusion criteria (17 listed)
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| GabapentinAfter group assignment but before taking any study medication, and again 17 days later, participants will have a Magnetic Resonance Imaging (MRI) exam after completing various assessments (clinical interview, questionnaires, etc.). Group A will receive gabapentin 2-3 times a day for a total of 17 days. | Drug | Group A - Gabapentin |
| PlaceboAfter group assignment but before taking any study medication, and again 17 days later, participants will have a Magnetic Resonance Imaging (MRI) exam after completing various assessments (clinical interview, questionnaires, etc.). Group A will receive placebo 2-3 times a day for a total of 17 days. | Drug | Group B - Placebo |
Primary outcome
Change in prefrontal GABA concentrations through Proton Magnetic Resonance Spectroscopy
Time frame: Baseline to end of treatment, approximately 17 days
Concentrations of GABA, normalized to water and corrected for CSF%, in dorsal anterior cingulate measured via Proton Magnetic Resonance Spectroscopy.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Sep 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
James J Prisciandaro, PhD principal investigator
Medical University of South Carolina
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Gabapentin in people with Bipolar Disorder and Cannabis Use, run by Medical University of South Carolina at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 17 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 9 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in prefrontal GABA concentrations through Proton Magnetic Resonance Spectroscopy (time frame: Baseline to end of treatment, approximately 17 days). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Sep 2026.