D-cycloserine Augmentation of Cognitive Remediation in Schizophrenia

The auditory discrimination task involved trials in which the subject differentiated between rapidly-presented frequency-modulated sweeps separated by a short interstimulus interval (ISI). In this task, sustained successful performance is more difficult with shorter stimulus presentations and ISIs (which were equal within a trial). Thus, our dependent measure was the shortest stimulus duration/ISI, in ms, for trials in which subjects were able to perform the task at 85% accuracy, referred to as ISI for simplicity. The shorter the score the better the performance on the task. Scores are reported for baseline and week 8.

Time frame: Baseline vs. Week 8

Population: 18 participants in each arm had baseline values available for analysis. 17 in the D-cycloserine arm and 15 in the placebo arm had week 8 values available for analysis.

Change of a composite score from baseline to week 8 on the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS). The MATRICS consists of 10 cognitive tasks that are used to calculate scores in 7 cognitive domains: speed of processing, attention/vigilance, working memory, verbal learning, visual learning, reasoning and problem solving, and social cognition. The raw scores on each cognitive task are transformed on a normative scale into t-scores, and then these scores are combined to calculate the domain scores. The composite score is calculated by averaging all domain t-scores to come up with one overall cognitive composite t-score. For all scores on the assessment, the higher the score the better the performance on the task.

Time frame: Baseline vs. Week 8

Population: 18 participants in each arm had baseline values available for analysis. 17 in the D-cycloserine arm and 15 in the placebo arm had week 8 values available for analysis.

The total scores from baseline and week 8 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 total score was computed by adding all the sub-scale total scores. Scores are reported for baseline and week 8.

Time frame: Baseline vs. Week 8

Population: 18 participants in each arm had baseline values available for analysis. 17 in the D-cycloserine arm and 15 in the placebo arm had week 8 values available for analysis.

Baseline scores on the Calgary Depression Scale for Schizophrenia (CDSS). Total CDSS scores range from 0-27. The assessment is comprised of 9 questions covering the topics of Depression, Hopelessness, Self Depreciation, Guilty Ideas of Reference, Pathological Guilt, Morning Depression, Early Wakening, Suicide, Observed Depression. Each item is scored on a scale from 0-3 (0 = absent, 1 = mild, 2 = moderate, 3 = severe). The total score is computed by adding up the individual scores of each item. The higher the score, the more prominent the symptoms of depression are for the participant.

Time frame: Baseline

Considering you total clinical experience with this patient population, how mentally ill is the patient at this time? 1=Normal, not at all, 2=Borderline mentally ill, 3=Mildy ill, 4=Moderately ill, 5=Markedly ill, 6=Severely ill, 7=Among the most extremely ill patients; a higher score indicates worse outcome

Time frame: Weeks 0 and 8, and Month 6 after cognitive remediation completion

Population: 18 participants in each arm had baseline data available for analysis. At week 8, 17 participants in the D-cycloserine group and 15 in the placebo group had data available. At month 6, 6 participants in the D-cycloserine group and 4 in the placebo group had data available.

The Global Assessment of Functioning Scale (GAS) measured at baseline. This scale measures social, occupational, and psychological functioning, on a scale of 0-100. The higher the score, the greater a participant's functioning level.

Time frame: Baseline

Baseline scores of the Heinrich Quality of Life Scale, a 21 item scale designed and validated to measure intrapsychic foundations, interpersonal relations, instrumental role, and common objects and activities in patients diagnosed with Schizophrenia. Patients are rated on each of the 21 items on a scale of 0-6. Total scores are computed by adding up the scores of each individual item, with a total score ranging from 0-126. Higher scores reflect higher functioning.

Time frame: Baseline

The baseline score on the positive symptom sub-scale of the Positive and Negative Syndrome Scale (PANSS). Total PANSS positive symptom sub-scale scores range from 7-49. The PANSS positive symptom sub-scale is comprised of 7 items rated on a scale of 1-7: delusions, conceptual disorganization, hallucinatory behavior, excitement, grandiosity, suspiciousness/persecution, and hostility. A score of one on each item 1 absent, 2 is minimal, 3 is mild, 4 is moderate, 5 is moderately severe, 6 is severe, and 7 is extreme. The total score was computed by adding all the items on the sub-scale together. The higher a score the more prominent a positive symptom is.

Time frame: Baseline

Each side effect is entered as either yes or no for having had any severity of the side effect at each visit.

Time frame: Weeks 0 - 8, and Month 6 after cognitive remediation completion

Population: 18 participants in each arm had baseline data available for analysis. At week 8, 17 participants in the D-cycloserine group and 15 in the placebo group had data available. At month 6, 6 participants in the D-cycloserine group and 4 in the placebo group had data available.