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

NCT05064319 | Recruiting Phase 2 FDA Drug

• 2 other identifiers: 00112593R01DA054275
• Study Type: interventional
• Target: 68
• Locations: 1 country
• Sites: 1

Brief 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. 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; Cannabis Use Disorder, Moderate; Cannabis Use Disorder, Severe

Outcome Measures

Primary Outcomes (1)

• 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.

  Baseline to end of treatment, approximately 17 days

Study Arms (2)

Group A - Gabapentin

EXPERIMENTAL

Drug: Gabapentin

Group B - Placebo

PLACEBO COMPARATOR

Drug: Placebo

Interventions

Gabapentin DRUG

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.

Group A - Gabapentin

Placebo DRUG

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.

Group B - Placebo

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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)

You may not qualify if:

• 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

Sponsors & Collaborators

• Medical University of South Carolina: lead
• National Institute on Drug Abuse (NIDA): collaborator

Study Sites (1)

Medical University Of South Carolina

Charleston, South Carolina, 29425, United States

RECRUITING

MeSH Terms

Conditions

Bipolar Disorder; Psychotic Disorders; Lymphoma, Follicular

Interventions

Gabapentin

Condition Hierarchy (Ancestors)

Bipolar and Related Disorders; Mood Disorders; Mental Disorders; Schizophrenia Spectrum and Other Psychotic Disorders; Lymphoma, Non-Hodgkin; Lymphoma; Neoplasms by Histologic Type; Neoplasms; Lymphoproliferative Disorders; Lymphatic Diseases; Hemic and Lymphatic Diseases; Immunoproliferative Disorders; Immune System Diseases

Intervention Hierarchy (Ancestors)

Amines; Organic Chemicals; gamma-Aminobutyric Acid; Aminobutyrates; Butyrates; Acids, Acyclic; Carboxylic Acids; Cyclohexanecarboxylic Acids; Acids, Carbocyclic; Cyclohexanes; Cycloparaffins; Hydrocarbons, Alicyclic; Hydrocarbons, Cyclic; Hydrocarbons; Amino Acids; Amino Acids, Peptides, and Proteins

Study Officials

• James J Prisciandaro, PhD

  Medical University of South Carolina

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Sara Hix

CONTACT

843-792-7500; hixs@musc.edu

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Study Record Dates

• First Submitted: September 22, 2021
• First Posted: October 1, 2021
• Study Start: February 24, 2022
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): June 30, 2026
• Last Updated: July 8, 2025

Record last verified: 2025-07

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)