Trial of D-Cycloserine in Schizophrenia

To characterize further the effects of D-cycloserine augmentation of antipsychotic treatment on negative symptoms, performance on neurocognitive tasks, and on markers for glutamatergic, dopaminergic and serotonergic function in serum and cerebrospinal fluid. To determine if negative symptoms and cognitive function improve over time, if these improvements meaningfully impact quality of life factors, if they correlate with markers of neuronal function, and if subpopulations can be identified according to response.

Dysfunction of glutamatergic neuronal systems has recently been implicated in the pathophysiology of schizophrenia based on the finding that non-competitive inhibitors of the NMDA receptor can reproduce in normals the positive symptoms, negative symptoms, and cognitive deficits of schizophrenia. Furthermore, glutamatergic dysfunction may alter forebrain dopaminergic neuronal activity, a system central to the antipsychotic action of typical neuroleptics. It is believed that enhancing NMDA receptor function by systemic treatment with D-cycloserine, a partial agonist at the glycine modulatory site of the NMDA receptor, will reduce symptoms in schizophrenia.

Sixty schizophrenic outpatients with prominent, primary negative symptoms are treated with antipsychotic medication and are randomly assigned to D-cycloserine or placebo for a 6-month, fixed-dose trial. The primary outcome measure is the total score on the Scale for Assessment of Negative Symptoms (SANS). A neuropsychological battery, which emphasizes tests sensitive to prefrontal cortical function, is administered. Blood is obtained at several time points and CSF is obtained at Week 8 for assay of concentrations of D-cycloserine, glutamate, HVA, and 5HIAA.

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Key information

Conditions

Schizophrenia Mental Disorders Schizophrenia Spectrum and Other Psychotic Disorders

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

About this study

To characterize further the effects of D-cycloserine augmentation of antipsychotic treatment on negative symptoms, performance on neurocognitive tasks, and on markers for glutamatergic, dopaminergic, and serotonergic function in serum and cerebrospinal fluid. To determine if negative symptoms and cognitive function improve over time, if these improvements meaningfully impact quality of life factors, if they correlate with markers of neuronal function, and if subpopulations can be identified according to response.

Dysfunction of glutamatergic neuronal systems has recently been implicated in the pathophysiology of schizophrenia based on the finding that non-competitive inhibitors of the NMDA receptor can reproduce in normals the positive symptoms, negative symptoms and cognitive deficits of schizophrenia. Furthermore, glutamatergic dysfunction may alter forebrain dopaminergic neuronal activity, a system central to the antipsychotic action of typical neuroleptics. It is believed that enhancing NMDA receptor function by systemic treatment with D-cycloserine, a partial agonist at the glycine modulatory site of the NMDA receptor, will reduce symptoms in schizophrenia.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Diagnosis of Schizophrenia as per DSM IV criteria
Have been treated for at least 6 months with any conventional neuroleptic
Have prominent negative symptoms as defined by a total score of 40 or greater on the scale for the assessment of negative symptoms (SANS)

Exclusion criteria

Active alcohol or drug abuse
Unstable Medical Illness, seizure disorder, or other serious neurological disorder
Pregnant or Nursing
Unable to complete a cognitive battery

Treatment and study plan

D-cycloserine

Drug

50 mg/daily by mouth

Other names: Cycloserine

Placebo

Drug

50 mg/day of placebo by mouth

Primary outcomes

Scale for the Assessment of Negative Symptoms (SANS)

Time frame: Baseline, Week 4, Week 8

The slope of SANS total score from baseline to week 8 in the treatment and placebo groups on the scale for the assessment of negative symptoms (SANS) total score. Total SANS scores range from 0-100. The SANS is comprised of 5 subscores: Affective Flattening or Blunting (score range 0-35), Alogia (score range 0-20), Avolition-Apathy (score range 0-15), Anhedonia-Asociality (score range 0-20), and Attention (0-10). For each scale, the higher the score the more prominent the negative symptoms were. The slopes were obtained by plotting the group SANS total score mean for treatment vs. placebo on Baseline, Week 4, and Week 8 and performing a random slopes model.

Sponsors and collaborators

Lead sponsor

Massachusetts General Hospital

Other

Registry information

Official study title

A Six Month, Placebo-Controlled Trial of D-Cycloserine Co-Administered With Conventional Antipsychotics in Schizophrenia Patients

Important dates

Study start: 1996
Primary completion: 2002
Study completion: 2002
First posted: Nov 3, 1999
Registry last updated: Sep 10, 2014

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed