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

Purpose

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

Eligibility

Eligible Ages
Between 18 Years and 65 Years
Eligible Genders
All
Accepts Healthy Volunteers
No

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)

Study Design

Phase
Phase 2
Study Type
Interventional
Allocation
Randomized
Intervention Model
Parallel Assignment
Primary Purpose
Treatment
Masking
Triple (Participant, Care Provider, Investigator)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Group A - Gabapentin
  • Drug: Gabapentin
    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.
Placebo Comparator
Group B - Placebo
  • Drug: Placebo
    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.

Recruiting Locations

More Details

Status
Recruiting
Sponsor
Medical University of South Carolina

Study Contact

Sara Hix
843-792-7500
hixs@musc.edu

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