This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for D-Cycloserine Augmentation of Therapy for Pediatric Obsessive-Compulsive Disorder (NCT00864123), a randomized phase 2 study. The primary outcome is Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS; Scahill et al., 1997)..
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00864123 |
| Phase | Phase 2 |
| Condition | Obsessive-compulsive Disorder |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Enrollment | 30 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of South Florida |
| Results posted | Yes |
2. Clinical Question
Population
Children and adolescents aged 8-17 with a primary diagnosis of obsessive-compulsive disorder were the intended population. The registry summary says 40 were to be screened; the recorded enrollment was 30. The record does not report participant characteristics for those enrolled or how many met each eligibility criterion.
Intervention
Cognitive-behavioral therapy plus D-cycloserine. The arm description specifies 10 therapy sessions and a pill taken one hour before sessions 4-10. The number of pills depended on the child's weight, with each pill containing 25mg of D-cycloserine.
Comparator
Cognitive-behavioral therapy plus placebo. This arm also received 10 therapy sessions and a placebo pill one hour before sessions 4-10. The registry record describes the study as randomized, placebo-controlled, and quadruple-masked.
Primary question
The primary measure was the Children's Yale-Brown Obsessive-Compulsive Scale, assessed at baseline, mid-treatment, and post-treatment. The clinical question is whether the recorded symptom-severity scores differed between the therapy-plus-D-cycloserine and therapy-plus-placebo groups over those assessment points. A numerical between-group result is not reported in the registry record.
3. Trial Design
This was a phase 2, randomized, parallel-group study sponsored by the University of South Florida. The registry lists an enrollment of 30 and a completed status. The recorded start was 2008-01, and primary completion was 2009-11. These dates describe the registry record; they do not provide the timing of each participant's treatment or follow-up.
The two treatment conditions paired cognitive-behavioral therapy with either D-cycloserine or placebo. Both arm descriptions specify 10 therapy sessions. Participants were to take one or two pills one hour before sessions 4-10, with the pill count depending on weight. The placebo arm's pills contained 25mg of placebo, while the intervention arm's pills contained 25mg of D-cycloserine.
The registry describes the study as quadruple-masked. It does not identify in the record which four roles were masked or explain how masking was maintained. Random allocation can help make baseline differences less systematic between groups, while masking can reduce some expectations-related influences on care or assessment. Those are general design principles; they do not establish that the groups were balanced or that masking was successful in this trial.
The registry summary describes 40 children and adolescents aged 8-17 as the intended number to screen, followed by random assignment if eligibility criteria were met. That screening figure is not the same as the recorded enrollment of 30, and the record does not report how many people were screened, excluded, randomized, or analyzed. It also does not report the allocation sequence, allocation concealment, protocol deviations, or the detailed statistical analysis plan.
4. Participant Flow and Accounting
The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.
Before assignment: Excluded (n = 22) Not interested in participating in study (n=9) Changing medication at Baseline (n=5) Did not receive at least one DCS dose (n = 4) History of adequate CBT course (n=2) Met criteria for comorbid autism (n=1) Did not show up for pre-treatment assessment (n=1)
Overall Study
| Stage | Cognitive-behavioral Therapy + Placebo | Cognitive-behavioral Therapy + D-cycloserine |
|---|---|---|
| STARTED | 15 | 15 |
| COMPLETED | 15 | 15 |
| NOT COMPLETED | 0 | 0 |
5. Baseline Characteristics
The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.
| Characteristic | Unit | Cognitive-behavioral Therapy + Placebo | Cognitive-behavioral Therapy + D-cycloserine | Total |
|---|---|---|---|---|
| Participants analysed | 15 | 15 | 30 | |
| Age, Categorical: <=18 years | Participants | 15 | 15 | 30 |
| Age, Categorical: Between 18 and 65 years | Participants | 0 | 0 | 0 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 |
| Age Continuous | years | 12.5 (SD 3.5) | 11.9 (SD 1.9) | 12.2 (SD 2.8) |
| Sex: Female, Male: Female | Participants | 6 | 5 | 11 |
| Sex: Female, Male: Male | Participants | 9 | 10 | 19 |
| Region of Enrollment: United States | participants | 15 | 15 | 30 |
6. Primary Endpoint
The registry lists the primary outcome as Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS; Scahill et al., 1997)., measured over Baseline, Mid-Treatment, Post-treatment.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS), a 10-item, semi-structured measure of the severity of obsessions and compulsions over the previous week. The registry states that scores range from 0-40, with higher scores representing more severe symptoms. The measure is recorded as a continuous outcome summarized by a mean and standard deviation.
A severity scale can represent symptom burden in a form that can be compared across participants and groups. In general, repeated measurements can also describe how scores change during treatment. For this trial, the registry lists baseline, mid-treatment, and post-treatment as assessment points. That schedule alone does not establish which time contrast or group comparison was designated for the primary statistical test.
The outcome's definition gives clinical context to a score, but interpretation of a treatment comparison also requires the observed group values, an estimate of the between-group difference, and information about uncertainty. Those numerical primary outcome results are not reported in the registry record. The record therefore identifies what was measured and when, but does not establish the size or direction of any difference between the two groups.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a randomized comparison of cognitive-behavioral therapy plus D-cycloserine with the same therapy plus placebo. It also identifies the CY-BOCS as the primary outcome and lists baseline, mid-treatment, and post-treatment assessment points. However, numerical CY-BOCS results are not reported in the registry record. No group means, standard deviations, treatment contrast, confidence interval, or primary-outcome p-value is available in the record.
Without those results, the direction and magnitude of the observed outcome cannot be described. It is not possible to tell from the registry record whether mean scores were higher or lower in either arm at any assessment point, how much participants' scores changed, or how precisely any between-group estimate was determined. No conclusion about a treatment effect should be inferred from the trial's design or from the fact that the study was completed.
The enrollment figure of 30 describes the recorded trial enrollment, not the number contributing usable CY-BOCS measurements at each assessment. The registry record does not report the number analyzed, participant withdrawals, missing observations, or the reasons for missing data. It therefore cannot establish whether the enrolled groups remained comparable in the outcome analysis or how incomplete follow-up may have affected an estimate.
The record reports no serious adverse events and no other adverse events in either group among 15 participants at risk per group. These are reported counts, not evidence that no adverse symptoms of any kind occurred: the adverse symptom checklist is listed as a secondary outcome, but its results are not reported in the registry record. Death counts are not reported in the registry record.
Any planning illustration based on an observed effect should be kept separate from trial findings. Such calculations are planning aids rather than observed power, and the registry record does not give a primary-outcome effect estimate in the information. The central statistical limitation is therefore the absence of the primary outcome results, not a basis for treating the study as positive or negative.
9. Statistical Methods Explained
The registry describes random allocation to two parallel treatment groups. In a randomized trial, allocation is intended to reduce systematic differences between groups at the start of treatment. Randomization does not guarantee that all characteristics will be identical, especially in a small study, and the record does not report baseline characteristics or details of the allocation procedure. The study is also described as quadruple-masked, but the identities of the masked roles and any assessment of masking success are not reported in the registry record.
What does a mean and standard deviation describe?
The primary outcome is continuous and is described using a mean and standard deviation. A mean is a measure of the group's average score. A standard deviation describes how spread out individual scores are around that average. These quantities serve different purposes: the mean locates the group average, while the standard deviation describes variation among participants. Neither alone gives the uncertainty of a comparison between groups.
For a treatment comparison, an effect estimate would usually express how the groups differ on the outcome, with an uncertainty measure such as a confidence interval. In general, a confidence interval gives a range of values compatible with the data and the method used to calculate it; it is not a guarantee that the true effect lies inside that particular interval. A p-value, if reported, addresses compatibility of the data with a specified statistical null model. It does not state the probability that a treatment works, and it does not convey the size or clinical importance of an effect by itself. No primary-outcome effect estimate, confidence interval, or p-value is reported in the registry record.
How do the assessment points affect interpretation?
The CY-BOCS was scheduled at baseline, mid-treatment, and post-treatment. Repeated measurements can be analyzed in different ways. For example, an analysis may compare groups at a specified follow-up point while accounting for baseline, or model the pattern of scores across visits. These approaches answer related but not identical questions. The registry record does not report which comparison, model, or contrast was used, nor does it reduce the listed assessments to a single primary comparison.
When measurements from the same participant are modeled together, they are not independent observations: scores from one participant can be more alike than scores from different participants. General statistical methods for repeated measurements account for that within-participant association. The choice of method can affect standard errors and the resulting uncertainty. The specific covariance structure or repeated-measures approach is not reported in the registry record, so no such method should be attributed to this trial.
What is needed to judge uncertainty?
Statistical precision depends on the amount of information in the analysis, including the number of participants with usable measurements and the variation in their scores. The recorded enrollment does not reveal how many participants contributed to each outcome assessment. Neither a sample-size figure nor a completed status can substitute for an outcome estimate and its uncertainty. Since the primary numerical results are not reported in the registry record, the precision of the treatment comparison cannot be assessed.
As general statistical context, a wider confidence interval indicates less precision than a narrower one, while the interval's location describes which effect values are compatible with the data under the chosen method. An interval can include values on both sides of no difference and still be compatible with effects of meaningful size in either direction. Interpretation should therefore consider both the estimate and its interval, rather than relying on a thresholded p-value alone. The necessary numerical results are not available in the registry record.
What can planning calculations say?
The registry's stated sample-size assumptions describe planning illustrations based on an observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. The stated effect to detect is a fraction of the observed effect. Such calculations are not observed power and do not report what happened in the trial. Participants-per-arm figures, when used for planning, are prospective illustrations under assumptions rather than observed sample sizes or evidence of an effect.
The registry record does not report a single reduced primary comparison across the listed time points, and it does not report the numerical CY-BOCS effect needed to interpret an effect-based illustration. No sample-size justification from the original design, interim analysis plan, or trial-specific statistical analysis details are reported in the registry record. General statistical concepts explain how these methods can work; they do not fill in the trial's unreported choices or results.
Why do multiplicity and missingness matter?
When several outcomes, visits, or contrasts are examined, the chance of at least one apparently notable finding can increase if each is tested separately without accounting for that multiplicity. A prespecified primary contrast and a planned strategy for secondary analyses help clarify which result carries the main inferential weight. The registry lists three outcome measures and identifies the CY-BOCS as primary, but it does not report a multiplicity adjustment, a hierarchy of tests, or the analysis plan for the multiple assessment points.
Missing outcomes can also affect interpretation. If missingness is related to participants' symptoms, treatment experience, or other factors, an analysis restricted to observed scores may not represent all randomized participants. Statistical methods can address missing data under stated assumptions, but those assumptions and methods must be reported to assess their plausibility. The registry record does not report missing-data handling, analysis populations, or participant flow through the outcome assessments.
10. Multiplicity, Missing Data and Analysis Populations
The registry identifies the CY-BOCS as the primary measure and lists baseline, mid-treatment, and post-treatment assessments. It also lists Clinical Global Impression - Severity and the Adverse Symptom Checklist as secondary outcomes. Considering several outcomes or several contrasts can create multiplicity: if many tests are run, some may appear notable by chance. A prespecified primary contrast and an explicit strategy for secondary tests help distinguish confirmatory analyses from exploratory ones. A multiplicity procedure or hierarchy is not reported in the registry record.
The primary outcome has multiple assessment points, but the registry record does not identify a single time-point comparison or describe how the repeated measurements were analyzed. It does not report whether baseline values were included as covariates, which outcome contrasts were tested, or how any secondary analyses were handled. Thus, the listed endpoint schedule is not enough to reconstruct the inferential plan.
The record does not report the number of participants with outcome data at each visit, withdrawals, reasons for missing observations, or the handling of missing data. It also does not state whether analyses used all randomized participants, only participants who completed treatment, or another analysis population. These details matter because different analysis sets and missing-data assumptions can yield different estimates. They are not reported in the registry record, so the potential influence of incomplete data cannot be evaluated.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Cognitive-behavioral Therapy + Placebo | 0 | 15 | 0.0% |
| Cognitive-behavioral Therapy + D-cycloserine | 0 | 15 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Cognitive-behavioral Therapy + Placebo | 0 of 15 |
| Cognitive-behavioral Therapy + D-cycloserine | 0 of 15 |
The posted adverse-event figures list 15 participants at risk in each group. The registry reports zero serious adverse events and zero other adverse events for the cognitive-behavioral therapy plus placebo group, and the same reported counts for the cognitive-behavioral therapy plus D-cycloserine group. No serious adverse-event terms are listed.
These figures should be read as registry-reported counts for the categories shown. They do not establish that no symptoms or health events occurred outside those categories, and they do not describe event timing, severity beyond the serious/non-serious distinction, or individual participants' experiences. The Adverse Symptom Checklist is listed as a secondary outcome, but checklist results are not reported in the registry record. Death counts are not reported in the registry record.
With no further event descriptions or comparative analysis, the counts do not quantify a difference in safety between the groups. They are a limited account of the adverse-event categories reported, rather than a complete characterization of tolerability.
12. What the Result Does, and Does Not, Mean
This trial record describes a randomized, parallel comparison of cognitive-behavioral therapy plus D-cycloserine with cognitive-behavioral therapy plus placebo in a pediatric obsessive-compulsive disorder study. It identifies a continuous primary outcome, the CY-BOCS, and the planned assessment points. These details clarify the clinical question and the type of outcome intended to address it.
The record does not report numerical primary outcome results. Consequently, it cannot establish the observed direction, magnitude, or precision of a group difference, or show whether scores changed differently between treatment conditions. The record's completed status does not supply those missing results. Nor can the adverse-event counts replace an efficacy analysis or establish the absence of all adverse symptoms.
In general, a treatment comparison is most informative when the estimate, uncertainty interval, analysis population, and handling of missing data are available together. A point estimate describes the observed contrast, while its interval communicates precision under the chosen model. Without those results and methods, readers cannot distinguish a small, precise difference from a larger but uncertain one, or assess whether conclusions depend on modeling choices.
The registry record therefore supports a description of study design and planned measurement, but not a conclusion about the clinical or statistical result of the primary comparison. It also cannot establish why the study enrolled 30 rather than the 40 described for screening in the summary, since participant flow and the enrollment process are not reported in the registry record.
13. Why This Trial Matters Statistically
The trial is statistically informative as an example of why a clear design description and numerical outcome reporting serve different purposes. Randomization, masking, a parallel comparison, and a named primary outcome describe how the investigators intended to compare the treatment conditions. They do not reveal what the comparison found. For interpretation, readers also need group-level outcome summaries, an effect estimate, and a measure of uncertainty.
The repeated CY-BOCS assessments raise a substantive analysis question: the clinical interpretation depends on which time point or pattern of change is compared between groups. Listing baseline, mid-treatment, and post-treatment does not specify the statistical contrast. If that choice is not reported, the reader cannot tell which of several possible comparisons supports a conclusion or how multiplicity was addressed.
The recorded enrollment of 30 and the summary's intended screening figure of 40 also illustrate why participant flow matters. Enrollment alone does not show how many people were randomized, completed treatment, or contributed data at each visit. Those details are needed to assess missingness and the information available for estimating a treatment difference.
Finally, reported adverse-event counts and a listed symptom checklist are not interchangeable evidence. The counts describe the reported serious and other adverse-event categories, while the checklist results are not reported in the registry record. Keeping these distinctions clear prevents readers from treating a limited set of event counts as a complete safety analysis.
14. Limitations
- The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
- Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.
The primary limitation for interpretation is that CY-BOCS results are not reported in the registry record. There are no recorded group means or standard deviations, no numerical contrast, and no confidence interval or p-value in the information available. The multiple assessment points are described, but the primary comparison across them is not specified.
The registry record also does not report participant flow, baseline characteristics, outcome completion by visit, withdrawals, or reasons for missing data. Although enrollment is recorded as 30 and the summary describes 40 intended for screening, the record does not explain the relationship between those figures. The number analyzed for any outcome is not reported.
Further trial-specific analysis details are absent, including the statistical model, handling of repeated measurements, adjustment for baseline, multiplicity strategy, analysis populations, and missing-data methods. The registry does not report a sample-size justification from the original design or interim analyses. These omissions mean that neither the estimation strategy nor its assumptions can be evaluated from the record.
The safety information is also limited: the record gives counts for serious and other adverse events but does not report the listed adverse symptom checklist results. Death counts are not reported in the registry record. The fourfold masking description does not specify who was masked or whether masking was assessed. Together, these gaps limit assessment of the trial's findings, but they do not establish that the study was conducted incorrectly or that any particular result occurred.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: D-Cycloserine Augmentation of Therapy for Pediatric Obsessive-Compulsive Disorder — NCT00864123.
- Registry record last updated 2012-10-17; status last verified 2012-09.
- Results first posted 2012-10-17.
- Data retrieved from ClinicalTrials.gov on 2026-11-09.
- Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.
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18. Record Summary
The registry record describes a completed phase 2, randomized, parallel, quadruple-masked study sponsored by the University of South Florida, with enrollment of 30. The study compared cognitive-behavioral therapy plus D-cycloserine with cognitive-behavioral therapy plus placebo in pediatric obsessive-compulsive disorder. Both arms were described as receiving 10 therapy sessions, with a study pill before sessions 4-10.
The primary measure was the CY-BOCS, assessed at baseline, mid-treatment, and post-treatment. Numerical primary outcome results and the statistical analysis details needed to interpret a group difference are not reported in the registry record. The registry reports zero serious and zero other adverse events in each group among 15 participants at risk per group; adverse symptom checklist results and death counts are not reported in the registry record.