Examination of Glutamate and mGluR5 in Psychiatric Disorders

NCT ID: NCT02727972

Last Updated: 2025-12-30

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 180 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2012-02-21
• Study Completion Date: 2022-01-13

Brief Summary

This research study is designed to look at the involvement of the glutamate system in depression. Each subject will undergo a screening appointment to determine study eligibility. Thereafter, the study will take 2 or 3 visits depending on schedule availability and will consist of one MRI scan, and PET scan. Subjects will also participate in cognitive testing. Depending on camera time, staff availability and subject schedule, total study participation may last 1-2 months.

Detailed Description

With the recent advancements in positron emission tomography (PET) and radioligand development, the investigators are now able to image and quantify the metabotropic glutamatergic system (mGluR5) in vivo in human subjects. The study proposes a novel investigation of mGluR5 in depression to obtain critical data to advance understanding of the etiology of depression and its associated symptoms of cognitive dysfunction.

Aim 1: To determine mGluR5 availability in individuals with mood disorders compared to healthy controls as measured with PET brain imaging.

Hypothesis 1: The study hypothesizes a decrease in mGluR5 availability in individuals with mood disorders in regions responsible for emotional and cognitive processes, including the amygdala, hippocampus, thalamus, anterior cingulate, and frontal cortices.

Aim 2: To determine if glutamate cycling in individuals with mood disorders is altered as compared to healthy controls as measured with [1H]MRS and [13C]MRS.

Hypothesis 2: The study hypothesizes an increase in glutamate number in individuals with mood disorders as compared to controls.

Aim 3: To determine if the PET alterations in the glutamatergic system of depressed individuals are associated with cognitive deficits observed in depression, including concentration, attention, memory, distractibility, and startle.

Hypothesis 3: The study hypothesizes a positive relationship between mGluR5 availability and cognitive functioning, such that individuals with higher receptor availability will perform better on tests of concentration, attention, memory, distractibility, and startle than individuals with lower receptor availability.

Aim 4: To determine mGluR5 availability in individuals with anxiety and schizophrenia compared to healthy controls as measured with PET brain imaging.

Hypothesis 4: Anxiety disorders such as obsessive compulsive disorder, and delusional disorders such as schizophrenia are frequently comorbid with mood disorders, and the glutamatergic system has been observed to be compromised in these individuals as well. This study will examine if there are regional differences in mGluR5 availability between individuals with depression, bipolar disorder, obsessive compulsive disorder, and schizophrenia.

Aim 5: To examine whether changes in mGluR5 availability are dependent on state, or whether the lower availability is due to trait.

Hypothesis 5: Due to changes in endogenous GLU shown with MRS studies, this study hypothesizes normalization (or increase) in mGluR5 availability in euthymia as compared to depressed state.

Conditions

Major Depressive Disorder; Post-Traumatic Stress Disorder; Bipolar Disorder

Keywords

depression; bipolar; post-traumatic stress disorder; mood disorders; PET; mGluRr; glutamate system; MRI

Study Design

• Allocation Method: NON_RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

Cognitive Testing

Cognitive assessments

Group Type: OTHER

Cognitive Testing

Intervention Type: BEHAVIORAL

Verbal assessments as well as computer testing.

Magnetic Resonance Imaging

All subjects will have one MRI with a possibility of one functional MRI (fmri).

Group Type: ACTIVE_COMPARATOR

MRI

Intervention Type: OTHER

Anatomical MRIs will be performed on a Siemens 3T Trio at Yale. MR acquisition will be a Sag 3D magnetization-prepared rapid gradient-echo (MPRAGE) sequence with 3.34 ms echo time, 2,500 ms repetition time, 1,000 ms inversion time, 7 degree flip angle, and 180 Hz/pixel bandwidth. The image dimensions will be 256 x 256 x 176 and pixel size 0.98 x 0.98 x 1.0 mm. Resting state MRIs will also be obtained as follows: We will be doing 2 six minute scans with subjects in the scanner, eyes open, fixating a cross. TR = 3 secs 45 slices x 3 mm slice thickness = 13.5 cm. In plane resolution = 3 x 3 mm, slice acquisition order = ascending.

Positron Emission Tomography

All subjects will have PET scan using FPEB or ABP688.

Group Type: ACTIVE_COMPARATOR

PET

Intervention Type: RADIATION

High Resolution Research Tomograph (HRRT), the highest resolution human brain scanner available, or HR+ will be used to image subjects. Vital signs (blood pressure, pulse, respiration) will be obtained before and after radiotracer administration. An antecubital venous catheter will be used for IV administration of the radiotracer and for venous blood sampling. A radial artery catheter will be inserted by an experienced physician before the PET scan. At the beginning of each scan, the subject's head will be immobilized and a 6 minute transmission scan using an orbiting 137Cs (HRRT) or 68GE (HR+) point-source is obtained and used for attenuation correction. PET scans will be acquired using bolus or bolus plus constant infusion administration of FPEB or ABP688.

Interventions

Cognitive Testing

Verbal assessments as well as computer testing.

Intervention Type: BEHAVIORAL

MRI

Anatomical MRIs will be performed on a Siemens 3T Trio at Yale. MR acquisition will be a Sag 3D magnetization-prepared rapid gradient-echo (MPRAGE) sequence with 3.34 ms echo time, 2,500 ms repetition time, 1,000 ms inversion time, 7 degree flip angle, and 180 Hz/pixel bandwidth. The image dimensions will be 256 x 256 x 176 and pixel size 0.98 x 0.98 x 1.0 mm. Resting state MRIs will also be obtained as follows: We will be doing 2 six minute scans with subjects in the scanner, eyes open, fixating a cross. TR = 3 secs 45 slices x 3 mm slice thickness = 13.5 cm. In plane resolution = 3 x 3 mm, slice acquisition order = ascending.

Intervention Type: OTHER

PET

High Resolution Research Tomograph (HRRT), the highest resolution human brain scanner available, or HR+ will be used to image subjects. Vital signs (blood pressure, pulse, respiration) will be obtained before and after radiotracer administration. An antecubital venous catheter will be used for IV administration of the radiotracer and for venous blood sampling. A radial artery catheter will be inserted by an experienced physician before the PET scan. At the beginning of each scan, the subject's head will be immobilized and a 6 minute transmission scan using an orbiting 137Cs (HRRT) or 68GE (HR+) point-source is obtained and used for attenuation correction. PET scans will be acquired using bolus or bolus plus constant infusion administration of FPEB or ABP688.

Intervention Type: RADIATION

Other Intervention Names

Magnetic Resonance Imaging; Positron Emission Tomography

Eligibility Criteria

Inclusion Criteria

• Subjects will be between the ages of 18-70 years old
• English speaking
• No other DSM-5 diagnosis present, besides required as below

• Clinical diagnosis of a current depressive episode
• Medication-free for at least 2 weeks or medicated with a permissible medication

• Clinical diagnosis of current PTSD as per DSM-5
• Medication free for at least 2 weeks or medicated with a permissible medication

• No current, or history of, any DSM-5 diagnosis

Exclusion Criteria

• Have a current or past significant medical, neurological or metabolic disorder or head injury that lead to significant long term decline in cognitive abilities as seen by decline in grades or work performance
• Have significant medical illness such that would contraindicate study participation based on above criteria and PI/MD history review
• Have active, significant suicidal ideation
• Have implanted metallic devices or any MR contraindications
• Are women who are pregnant or breastfeeding
• Met DSM-5 criteria for mild substance use disorder (except nicotine and marijuana) within the past 6 months or met DSM-5 criteria for moderate to severe substance use disorder (except nicotine and marijuana) within the past year
• Have history of prior radiation exposure for research purposes within the past year such that participation in this study would place them over FDA limits for annual radiation exposure. This guideline is an effective dose of 5 rem received per year
• Have given a blood donation within eight weeks of the start of the study
• Have history of a bleeding disorder or are currently taking anticoagulants (such as Coumadin, Heparin, Pradaxa, Xarelto)

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 70 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

VA Office of Research and Development

FED

Sponsor Role: collaborator

Yale University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Irina Esterlis, PhD

Role: PRINCIPAL_INVESTIGATOR

Yale University

Locations

PET Center

New Haven, Connecticut, United States

Countries

United States

Other Identifiers

1101007933

Identifier Type: -

Identifier Source: org_study_id