Investigation of Cocaine Addiction Using mGluR5 PET and fMRI

Phase 1

Completed

• Conditions: Cocaine Dependence
• Interventions: Behavioral: Psychiatric and Cognitive Testing; Drug: Cocaine Self-adminstration; Radiation: Positron Emission Tomography; Other: Magnetic Resonance Imaging

• Registration Number: NCT03471182
• Lead Sponsor: Yale University

Brief Summary

The proposed research program will investigate the changes in brain chemistry and circuitry that 're-wire' the brain during chronic cocaine use, promote relapse, and complicate treatment efforts. Currently-using and non-treatment-seeking individuals with a cocaine use disorder will undergo a cocaine self-administration paradigm 2-5 days prior to completing positron emission tomography (PET) and functional magnetic resonance imaging (fMRI).

Detailed Description

Cocaine use disorder (CUD) remains a significant public health concern that is resistant to current treatments. Challenges to treating CUD include an imbalance in neurobiological systems that 're-wire' the brain such that appetitive and habitual processes influence decision-making and behavior. This research project aims to provide insight into this reorganized circuitry in CUD by investigating neurofunctional systems related to glutamatergic plasticity and functional brain networks during initial (2-5 days) abstinence. To target this potentially critical period of recovery, currently-using and non-treatment-seeking individuals with CUD will undergo a cocaine self-administration paradigm 2-5 days prior to completing \[18F\]FPEB positron emission tomography (PET) and functional magnetic resonance imaging (fMRI). Healthy comparison (HC) subjects that have participated in \[18F\]FPEB PET as part of other Yale approved protocols will be recruited to participate in the fMRI portion of this study.

Aim 1: To determine the availability of mGluR5 using \[18F\]FPEB PET during initial abstinence in individuals with CUD. The investigators hypothesize individuals with CUD, relative to HC, will exhibit concurrently and regionally specific increases (e.g., in the striatum) and decreases (e.g., in the prefrontal cortex) in mGluR5 availability.

Aim 2: To determine patterns of resting-state, response-inhibition, an automaticity related connectivity within and between large-scale functional networks using fMRI during initial abstinence in individuals with CUD. The investigators hypothesize network-based analyses of fMRI will reveal lower frontoparietal and greater limbic network modulation in CUD as compared to HC.

Aim 3: To explore the relationships between mGluR5 availability and functional network activity during initial abstinence in individuals with CUD. The investigators will perform multi-modal analysis of PET and fMRI data to examine links between molecular and functional systems in CUD using emerging 'fusion' approaches. While exploratory in nature, the investigators expect to find links between alterations in mGluR5 systems and functional reorganization in CUD (e.g., greater dorsostriatal mGluR5 may be linked to blunted frontoparietal inhibition).

Aim 4: To explore the relationships between mGluR5 availability, functional network activity (and their linkages) with cocaine self-administration, disease severity and chronicity, and psychometric assessments of impulsivity and compulsivity. While exploratory in nature, the investigators expect more substantial neurofunctional alterations during initial abstinence will be associated with greater cocaine self-administration, disease severity, impulsivity and compulsivity in individuals with CUD.

Study Timeline

• Study Start: 2018-02-26
• Study First Submitted: 2018-02-26
• Study First Submitted QC: 2018-03-13
• Study First Posted: 2018-03-20
• Primary Completion: 2022-08-18
• Study Completion: 2022-08-18
• Results First Submitted: 2023-08-09
• Results First Submitted QC: 2023-10-05
• Results First Posted: 2023-10-06
• Status Verified: 2024-02
• Last Update Submitted: 2024-02-27
• Last Update Posted: 2024-02-29

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 32

Inclusion Criteria

• All participants:

  • Age 21 - 60 years
  • Provide voluntary, written, informed consent
  • Physically healthy by medical history, physical, neurological, ECG, and laboratory examinations
  • For females: non-lactating, no longer of child-bearing potential or agreeing to practice effective contraception during the study (e.g., established use of oral, injected or implanted hormonal methods of contraception; placement of an intrauterine device [IUD] or intrauterine system [IUS]; barrier methods: condom or occlusive cap [diaphragm or cervical/vault caps] with spermicidal foam/gel/film/cream/suppository; male partner sterilization; true abstinence when this is in line with the preferred and usual lifestyle of the subject), and a negative serum pregnancy test

• Participants with a cocaine use disorder:

  • DSM-5 criteria for moderate or severe cocaine-use disorder
  • Recent street cocaine use in excess of quantities used in the current study
  • Intravenous and/or smoked (crack/freebase) cocaine use
  • Positive urine toxicology screen for cocaine

• Healthy comparison participants:

  • Successful completion of an [18F]FPEB scan as part of another Yale approved protocol as a healthy control/comparison subject

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Exclusion Criteria

• All participants:

  • Any condition that, in the opinion of investigators, would prevent compliance with the study protocol
  • A history of significant medical or neurological illness (e.g., coronary artery disease, significant anemia, seizures)
  • Current use of psychotropic and/or potentially psychoactive medications
  • Physical or laboratory evidence of pregnancy
  • Meet any additional PET/MR imaging-related exclusion criteria, including:
  • Presence of MRI incompatible implants and other contraindications for MRI (e.g., pacemaker, artificial joints, non-removable body piercings, etc.)
  • Participation in other research studies involving ionizing radiation within one year of the PET scans that would cause the participant to exceed the yearly dose limits
  • History of a bleeding disorder or are currently taking anticoagulants (such as Coumadin, Heparin, Pradaxa, Xarelto).
  • Claustrophobia
  • Severe motor problems that prevent the subject from lying still for PET/MR imaging
  • Complaints of chronic pain (e.g., as the result of rheumatoid arthritis)
  • Current, past or anticipated exposure to radiation in the work place

• Participants with a cocaine use disorder:

  • Other drug use disorder (except for tobacco-use disorder)
  • Less than 1 year of cocaine use disorder
  • A DSM-5 major psychiatric diagnosis (schizophrenia, bipolar disorder, etc.) unrelated to cocaine

• Healthy comparison participants:

  • Any DSM-5 major psychiatric diagnosis (schizophrenia, bipolar disorder, etc.), except tobacco-use disorder
  • Positive drug screen

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Psychiatric and Cognitive Testing	Psychiatric and Cognitive Testing	All participants will complete psychiatric assessment and cognitive testing.
Cocaine Self-adminstration	Cocaine Self-adminstration	This arm plans to assess the subjective (e.g., euphoric) and behavioral effects (e.g., self-administration) of cocaine in experienced, non-treatment seeking users of the drug in a human laboratory study of self-regulated cocaine administration.
Positron Emission Tomography	Positron Emission Tomography	All participants will complete a PET scan to assess mGluR5 receptors using \[18-F\]FPEB
Magnetic Resonance Imaging	Magnetic Resonance Imaging	All participants will complete one MRI scan to assess brain structure and function.

Primary Outcome Measures

Name	Time	Method
Regional Availability of Metabotropic Glutamate Type-5 Receptors (mGluR5)	Following 2-5 days of cocaine abstinence	Receptor availability assessed as the volume of distribution (VT) of \[18F\]FPEB radiotracer, measured using positron emission tomography (PET). Higher \[18F\]FPEB VT values indicate a greater availability of mGluR5 receptors.
Functional Brain Network Engagement Associated With Response Inhibition	Following 2-5 days of cocaine abstinence.	Independent component analysis (ICA) of functional MRI data separates brain activity associated with distinct functional networks. Comparing the activity in these networks to the fMRI task events using a regression analysis produces a beta-weight where a larger beta indicates the network was more activated or 'engaged' in processing the task demands. In this study, participants completed a Go/NoGo task to assess brain processing associated with infrequent-stimulus response inhibition (i.e., correct NoGo's) compared to frequent-stimulus responses (i.e., correct Go's).
Resting-state Functional Brain Network Activity, Fractional Amplitude of Low-frequency Fluctuations (fALFF)	Following 2-5 days of cocaine abstinence.	Independent component analysis (ICA) of functional MRI data separates brain activity associated with distinct functional networks. The fractional amplitude of low-frequency fluctuations (fALFF) during resting-state reflects a measure of the general health status of a network, comprised of both the strength of network activity and within-network connectivity absent of any specific cognitive demands.

Trial Locations

Locations (1)

Connecticut Mental Health Center; 🇺🇸 New Haven, Connecticut, United States