- ICH GCP
- US Clinical Trials Registry
- Clinical Trial NCT02769936
Glutamate, Learning, and Working Memory
The Effects of D-cycloserine on Neuroplasticity and Working Memory in Healthy Adults and Patients With Schizophrenia
Study Overview
Status
Conditions
Intervention / Treatment
Detailed Description
Background: Cognitive impairments in schizophrenia, such as deficits in plasticity and working memory, have been hypothesized to reflect dysfunction at the N-methyl-D-aspartate glutamate receptor (NMDAR). However, given that divergent properties of the NMDAR underlie its roles in plasticity versus working memory and that various aspects of NMDAR function are abnormal in schizophrenia, examining the effects of DCS in both healthy and patient populations is crucial.
Methods: The investigators used a single dose of the partial NMDAR agonist, d-cycloserine (DCS) to probe the effects of enhancing NMDAR signaling on working memory and plasticity. Working memory was assessed using a spatial n-back task. Plasticity was assessed using two learning tasks, the weather prediction task and information integration task, and an EEG paradigm that assesses changes in visual evoked potential amplitude following high frequency visual stimulation. Sixty-five healthy adults and forty-five schizophrenia patients were randomized to receive 100 mg acute DCS (healthy adult n = 32; schizophrenia n = 24) or placebo (healthy adult n = 33; schizophrenia n = 21).
Study Type
Enrollment (Actual)
Phase
- Phase 1
Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Description
Inclusion criteria for healthy subjects:
- between the ages of 18 and 30 years
- comfortable reading in English
- normal visual acuity or corrected vision
- normal or corrected hearing.
Exclusion criteria for healthy subjects:
- history or seizures or neurologic diseases
- currently prescribed medication for any psychiatric conditions
- any medical condition affecting fine motor movement of the hands
- pregnancy or suspected pregnancy
- use of recreational drugs or drugs taken not as prescribed in the past month
- having a full scale intelligence quotient (IQ) < 70, as assessed by the Wechsler Abbreviated Scale of Intelligence (WASI)
- having consumed alcohol in the 24 hours prior to the first lab visit
- known allergy to any antibiotics.
Inclusion criteria for patients with schizophrenia:
- between the ages of 18 and 50 years
- comfortable reading in English
- normal visual acuity or corrected vision
- normal or corrected hearing
- meets criteria for Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) diagnosis of schizophrenia.
Exclusion criteria for patients with schizophrenia:
- history or seizures or neurologic diseases
- currently prescribed Clozapine or medications contraindicated for DCS
- any medical condition affecting fine motor movement of the hands
- pregnancy or suspected pregnancy
- history of traumatic brain injury requiring hospitalization for 2 or more days
- IQ < 70, as assessed by the WASI
- having consumed drugs other than as prescribed in the 48 hour prior to the testing visit or having consumed alcohol in the 24 hours prior to the testing visit
- known allergy to any antibiotics
- current alcohol or substance dependence
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Basic Science
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Double
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
---|---|
Placebo Comparator: Healthy Adult - Placebo
Single dose placebo pill in healthy adults
|
Placebo administered orally as encapsulated pill
|
Experimental: Healthy Adult - D-cycloserine
Single 100 mg dose D-cycloserine pill in healthy adults
|
100 mg D-cycloserine administered orally as encapsulated pill
|
Placebo Comparator: Schizophrenia - Placebo
Single dose placebo pill in schizophrenia patients
|
Placebo administered orally as encapsulated pill
|
Experimental: Schizophrenia - D-cycloserine
Single 100 mg dose D-cycloserine pill in schizophrenia patients
|
100 mg D-cycloserine administered orally as encapsulated pill
|
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
---|---|---|
Performance on Information Integration Learning Task
Time Frame: Testing Day (i.e. approx 3-5 hrs following placebo or D-cycloserine administration)
|
Percent Correct Responses out of 240 trials (for schizophrenia patients) or 320 trials (for healthy adults) on the Information Integration Learning Task, which is a classification learning task in which participants learn to classify visual stimuli as category A or B following practice with stimuli and auditory feedback indicating correct versus incorrect responses.
|
Testing Day (i.e. approx 3-5 hrs following placebo or D-cycloserine administration)
|
Performance on Weather Prediction Learning Task
Time Frame: Testing Day (i.e. approx 3-5 hrs following placebo or D-cycloserine administration)
|
Percent Correct Responses out of 240 trials (for schizophrenia patients) or 320 trials (for healthy adults) on the Weather Prediction Learning Task, which is a probabilistic classification learning task in which participants learn to predict the weather (i.e.
"sun" or "rain" outcomes) based on combinations of cues that predict "sun" versus "rain" outcomes.
|
Testing Day (i.e. approx 3-5 hrs following placebo or D-cycloserine administration)
|
Performance on N-Back Working Memory Task
Time Frame: Testing Day (i.e. approx 3-5 hrs following placebo or D-cycloserine administration)
|
Percent Correct Responses out of 240 trials (for schizophrenia patients) or 320 trials (for healthy adults) on the N-Back Task, which is a spatial working memory task in which participants identify whether each new stimulus on the computer screen is in the same location as the stimulus shown in trials ago.
Patients with schizophrenia completed 80 trials at each of 3 working memory loads (0-, 1-, 2-back loads) and healthy adults completed 80 trials at each of 4 working memory loads (0-, 1-, 2-, 3-back loads).
|
Testing Day (i.e. approx 3-5 hrs following placebo or D-cycloserine administration)
|
Change in Visual Evoked Potential Amplitude using Electroencephalograph (EEG)
Time Frame: Testing Day (i.e. approx 3-5 hrs following placebo or D-cycloserine administration)
|
EEG data were recorded using a 128 channel cap while participants viewed a black and white checkerboard stimulus on a computer screen in 6 x 2-minute blocks before and after viewing a quickly flashing checkerboard stimulus for 2 minutes.
Change in the mean amplitude of the visual evoked potential from before versus after viewing the quickly flashing checkerboard stimulus was used to assess plasticity.
|
Testing Day (i.e. approx 3-5 hrs following placebo or D-cycloserine administration)
|
Collaborators and Investigators
Study record dates
Study Major Dates
Study Start
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Estimate)
Study Record Updates
Last Update Posted (Estimate)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
Other Study ID Numbers
- 13-000409
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.
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