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 Cognitive-Behavioral Therapy and Supportive Psychotherapy for Body Dysmorphic Disorder (NCT01453439), a randomized na study. The primary outcome is Body Dysmorphic Disorder Symptoms (as Measured by the BDD-YBOCS).
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01453439 |
| Phase | NA |
| Condition | Body Dysmorphic Disorder, Obsessive-Compulsive Spectrum Disorder, Anxiety Disorders |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 120 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Massachusetts General Hospital |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned people with body dysmorphic disorder (BDD). The registry describes an intent-to-treat analysis on 120 subjects randomized to the two therapies, while noting that assessments were missed because of patient cancellations or study dropouts. Further eligibility criteria and participant characteristics are not reported in the registry record.
Intervention
The intervention was Cognitive Behavioral Therapy (CBT), a behavioral intervention identified in the registry as treatment for BDD. Details of its therapeutic content, delivery, provider training, and session frequency are not reported in the registry record.
Comparator
The comparator was Supportive Psychotherapy (SPT), also identified as a behavioral intervention. The registry record names the two treatment groups but does not report the detailed content or delivery of SPT, or whether treatment exposure was matched between groups.
Primary question
The primary question was how BDD symptoms, measured with the BDD-YBOCS, changed during treatment and follow-up in the CBT and SPT groups. The treatment-period analysis covered weeks 0–24, and the follow-up-period analysis covered weeks 24 to 50. The registry record does not report the numerical group changes, a between-group estimate, or a confidence interval, so the relative symptom trajectories cannot be quantified from the record.
The study also aimed to examine predictors of improvement and listed secondary measures covering insight, depressive symptoms, life satisfaction, treatment credibility, beliefs about appearance, neuropsychological functioning, information processing, and disability. Results for those questions are not reported in the registry record. The clinical question is therefore clear at the level of design, but the posted information does not establish the size or precision of any treatment difference.
3. Trial Design
This was a randomized, parallel-group trial comparing CBT with SPT for BDD. The registry lists allocation as randomized and masking as single. It does not specify who was masked, how the random sequence was generated, or how allocation was concealed; these details are not reported in the registry record. The interventions are both classified as behavioral.
The registry lists enrollment as 120. It describes the primary-outcome population as an intent-to-treat analysis on 120 subjects randomized to either treatment, while noting that some assessments were missed because of patient cancellations or study dropouts. The exact numbers contributing to each primary-outcome analysis are not stated in the available record. The safety information separately gives group-specific numbers at risk.
The primary measure was BDD-YBOCS symptom severity. The record describes change from baseline, week 0, through post-treatment, week 24, with assessments every 4 weeks. Follow-up observations were measured at week 37 and week 50. Treatment effects were analyzed separately for the treatment period, weeks 0–24, and the follow-up period, weeks 24 to 50. The registry does not report the specific statistical model or estimates for either period.
The study is listed as phase NA and status completed. The sponsor is Massachusetts General Hospital. The recorded start was 2011-08, and primary completion was 2017-01-05. The record lists 11 outcome measures and 13 analyses. It does not report the full protocol, a sample-size justification, the masking procedures, or the 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.
Treatment Phase
| Stage | Cognitive Behavior Therapy (CBT) | Supportive Psychotherapy (SPT) |
|---|---|---|
| STARTED | 61 | 59 |
| COMPLETED | 44 | 48 |
| NOT COMPLETED | 17 | 11 |
Reasons for not completing this period:
| Reason | Cognitive Behavior Therapy (CBT) | Supportive Psychotherapy (SPT) |
|---|---|---|
| Withdrawal by Subject | 13 | 10 |
| Suicidal Ideation | 2 | 0 |
| Need for higher level of care | 1 | 1 |
| Therapist conflict of interest | 1 | 0 |
Follow-up
| Stage | Cognitive Behavior Therapy (CBT) | Supportive Psychotherapy (SPT) |
|---|---|---|
| STARTED | 44 | 48 |
| COMPLETED | 39 | 37 |
| NOT COMPLETED | 5 | 11 |
Reasons for not completing this period:
| Reason | Cognitive Behavior Therapy (CBT) | Supportive Psychotherapy (SPT) |
|---|---|---|
| Withdrawal by Subject | 0 | 1 |
| Lost to Follow-up | 5 | 10 |
Analysis population for the primary outcome, as defined in the registry: Intent to treat analysis on 120 subjects randomized to either CBT vs SPT. Some of the assessments visits were missed due to patient cancellations or study dropouts. The exact numbers analyzed are as specified below.
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 Behavior Therapy (CBT) | Supportive Psychotherapy (SPT) | Total |
|---|---|---|---|---|
| Participants analysed | 61 | 59 | 120 | |
| Age, Continuous | years | 34.5 (SD 14.5) | 33.4 (SD 11.5) | 33.9 (SD 12.9) |
| Sex: Female, Male: Female | Participants | 46 | 46 | 92 |
| Sex: Female, Male: Male | Participants | 15 | 13 | 28 |
| Race/Ethnicity, Customized: White, Non-Hispanic | Participants | 47 | 53 | 100 |
| Race/Ethnicity, Customized: White, Hispanic | Participants | 2 | 2 | 4 |
| Race/Ethnicity, Customized: Black | Participants | 1 | 1 | 2 |
| Race/Ethnicity, Customized: Asian/Pacific Islander | Participants | 6 | 1 | 7 |
| Race/Ethnicity, Customized: Other | Participants | 5 | 2 | 7 |
| Region of Enrollment: United States | Participants | 61 | 59 | 120 |
6. Primary Endpoint
The registry lists the primary outcome as Body Dysmorphic Disorder Symptoms (as Measured by the BDD-YBOCS), measured over Change in BDD-YBOCS from baseline (week 0) to post-treatment (week 24), assessed every 4 weeks. Followup phase data was measured at week 37 and week 50..
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was change in BDD symptoms, measured with the Yale-Brown Obsessive Compulsive Scale Modified for BDD (BDD-YBOCS). The registry describes it as a 12-item, semi-structured, clinician-administered measure of symptom severity. Its items are summed to produce a total score ranging from 0 to 48; higher scores indicate more severe BDD symptoms.
Change in a symptom score is used to describe how measured severity varies over time. Comparing changes between randomized groups can address whether their average symptom trajectories differ, subject to the analysis methods and completeness of the assessments. The registry defines separate treatment and follow-up periods rather than a single comparison spanning the entire observation period: treatment was weeks 0–24, and follow-up was weeks 24 to 50.
The record says assessments occurred every 4 weeks during the treatment period and notes follow-up measurements at week 37 and week 50. It does not report the actual score values, changes, variability estimates, between-group contrasts, or confidence intervals. It also does not state a threshold for a clinically important change. Consequently, the measurement and time frame are described, but the magnitude and precision of the trial’s primary endpoint findings are not reported in the registry record.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a randomized comparison of CBT and SPT and specifies BDD-YBOCS change as the primary symptom outcome. It describes separate analyses for the treatment period and follow-up period. However, the primary outcome has several time points and is not reduced in the record to one comparison. Numerical estimates for the groups, a treatment contrast, uncertainty intervals, and significance tests are not reported in the registry record. No conclusion about the direction, size, or precision of a difference between treatments can be drawn from the outcome information recorded.
The fact that the trial is randomized is relevant to how a comparison may be interpreted: random assignment is intended to make treatment groups comparable at the start on average. Randomization alone does not show whether the groups remained comparable in observed assessments, whether missing observations affected the analysis, or how large an estimated treatment difference was. The registry record does not provide those details or the primary analysis results.
The listed outcome is a mean-based continuous measure, with standard deviation named as its dispersion. General: a mean describes the average score or average change in a group, while a standard deviation describes variability among observations around that mean. A between-group contrast would express how the average changes compare. A confidence interval would describe the uncertainty around that contrast under the assumptions of the analysis. None of those primary outcome values is reported in the registry record.
The time structure matters. A difference during treatment and a difference during follow-up are distinct questions; the record states that treatment effects were analyzed separately across weeks 0–24 and weeks 24 to 50. It does not say whether an effect persisted, diminished, or changed direction, because the numerical trajectories and analysis results are not reported. The follow-up assessments at week 37 and week 50 are noted, but their group-level results are absent.
The record also lists secondary outcomes concerning insight, depressive symptoms, life satisfaction, treatment credibility, beliefs about appearance, neuropsychological functioning, information processing, and disability. Their names indicate a broad range of measured domains, but no results for them are reported. The record’s counts of 11 outcome measures and 13 analyses do not identify which analyses were confirmatory or exploratory, nor do they show how findings varied across measures.
The safety record reports serious adverse events and other adverse events separately by treatment group. Those counts describe reported events in the registry; without further detail, they do not quantify comparative risks or establish that treatment caused an event. Overall, the posted information supports a description of the trial question, endpoints, and recorded safety counts, but not an assessment of comparative efficacy or a precise account of treatment effects.
9. Statistical Methods Explained
The registry identifies the primary outcome as a continuous measure summarized by a mean and standard deviation. It also says that effects were analyzed separately during treatment and follow-up. The specific statistical methods used for these analyses are not reported in the registry record. The concepts below are general explanations of how continuous outcomes and trial comparisons are commonly interpreted, not claims about which procedures this trial used.
What does a mean change represent?
General: For a continuous outcome, a mean change is the average difference between a participant’s score at a later assessment and that participant’s baseline score, when the analysis defines change that way. A group mean change describes the average trajectory for that group. It does not imply that every participant changed by the same amount. The BDD-YBOCS score is defined so that higher scores indicate more severe symptoms, but the registry record does not provide observed score changes for either group.
Why report a standard deviation?
General: The standard deviation describes the spread of observations around their mean. Two groups can have the same average change but different variability, or different average changes with substantial overlap in individual scores. Reporting a mean without a measure of spread gives an incomplete description of the data. The registry identifies standard deviation as the dispersion measure for the primary outcome, but the corresponding values are not reported in the registry record.
What would a treatment contrast show?
General: A treatment contrast compares outcomes between the randomized groups. For a change outcome, the contrast could compare the groups’ average changes over a defined period. Its interpretation depends on the exact outcome definition and model. A confidence interval around a contrast conveys the range of values reasonably compatible with the data and analysis assumptions; it is not a guarantee that the true effect falls within a particular interval. The registry record does not report a primary contrast or confidence interval.
Why are treatment and follow-up periods separate?
General: An intervention-period analysis addresses outcomes while treatment is being delivered, whereas a follow-up analysis addresses outcomes after that period. These analyses can answer different questions about the time course of an outcome. A result from one period cannot automatically be treated as the result for another. Here, the registry describes weeks 0–24 as the treatment period and weeks 24 to 50 as follow-up, with follow-up measurements at week 37 and week 50. The analysis model and estimates for each period are not reported in the registry record.
How should repeated assessments be considered?
General: Repeated measurements on the same participant are related rather than independent observations. Statistical methods for repeated measures may account for that relationship and may use information from more than one assessment. Different models can make different assumptions about the pattern of change, correlations over time, and missing observations. The registry says assessments occurred every 4 weeks during treatment, but does not identify the model, covariance assumptions, or estimation method used.
What does randomization contribute?
General: Random assignment is designed to reduce systematic differences between groups at the point of assignment, supporting a fair comparison of assigned treatments. It does not prevent missed visits, guarantee balance in every characteristic, or by itself determine how to handle missing outcomes. The record identifies allocation as randomized, but details of sequence generation and allocation concealment are not reported in the registry record.
What can planning calculations tell a reader?
General: A sample-size calculation is a planning exercise about the amount of information that might be needed to detect an assumed effect under specified assumptions. It is not evidence that the observed effect is real, and it is not a measure of the probability that a finding is true. The registry’s stated illustration uses a two-sided significance level of 0.05, equal allocation, and a normal approximation, with the effect to detect defined as a stated fraction of the observed effect. For time-to-event tables, it specifies a total number of events using Schoenfeld; other calculations are described as participants per arm. These are planning assumptions, not the trial’s own design justification. That justification is not reported in the registry record.
The record does not report whether its own analyses used adjustment for baseline scores, how repeated measures were modeled, which test statistics were used, or whether confidence intervals were calculated. No statistical method beyond the endpoint summary and separate analysis periods should be attributed to the trial on the basis of the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 11 outcome measures and 13 analyses. It names the primary BDD-YBOCS outcome and several secondary outcomes, including measures of insight, depressive symptoms, life satisfaction, treatment credibility, beliefs about appearance, neuropsychological functioning, information processing, and disability. The record does not report which analyses were designated as primary, secondary, or exploratory beyond its naming of the primary outcome, nor does it describe a multiplicity adjustment or a hierarchy of tests. Whether and how the analysis plan accounted for multiple outcomes or time points is not reported in the registry record.
Multiplicity is a general statistical concern when many outcomes, time points, or comparisons are examined: the chance of at least one apparently unusual result can increase when results are interpreted individually without accounting for the broader set of analyses. This does not establish that the trial used or omitted any particular adjustment. The record does not give enough information to assess how multiplicity was handled.
The primary outcome population is described as an intent-to-treat analysis on 120 randomized subjects. The registry also states that some assessment visits were missed due to patient cancellations or study dropouts. It does not report the exact number of observations included in each outcome analysis, the amount or pattern of missing data, or the methods used to address missingness. It is therefore not possible from the record to assess whether the analysis retained all randomized participants in the relevant estimates or how missing assessments affected precision and potential bias.
General: an intent-to-treat approach typically aims to analyze participants according to their randomized group, but the label alone does not specify how missing outcome values are handled. The registry does not report imputation procedures, sensitivity analyses, or assumptions about why assessments were missing. It also does not report a per-protocol or other analysis population. These omissions limit interpretation of the analysis population and the robustness of the findings.
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 Behavior Therapy (CBT) | 5 | 61 | 8.2% |
| Supportive Psychotherapy (SPT) | 3 | 59 | 5.1% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Cognitive Behavior Therapy (CBT) | 0 of 61 |
| Supportive Psychotherapy (SPT) | 0 of 59 |
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 Behavior Therapy (CBT) | 34 of 61 |
| Supportive Psychotherapy (SPT) | 30 of 59 |
Most frequent serious adverse event terms
| Event term | Organ system | Cognitive Behavior Therapy (CBT) | Supportive Psychotherapy (SPT) |
|---|---|---|---|
| Suicidal ideation | Psychiatric disorders | 1 of 61 | 1 of 59 |
| Increase in BDD and depressive Symptoms | Psychiatric disorders | 1 of 61 | 0 of 59 |
| Self-harm | Psychiatric disorders | 1 of 61 | 0 of 59 |
| Negative reaction to anesthesia | Gastrointestinal disorders | 1 of 61 | 0 of 59 |
| Pain felt in one arm for a couple of days | General disorders | 1 of 61 | 0 of 59 |
| Mononucleosis | Infections and infestations | 0 of 61 | 1 of 59 |
| Cardiac surgery | Cardiac disorders | 1 of 61 | 0 of 59 |
| Anaphylactic shock | Immune system disorders | 0 of 61 | 1 of 59 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Cognitive Behavior Therapy (CBT) | Supportive Psychotherapy (SPT) |
|---|---|---|---|
| Increased anxiety and/or depression | Psychiatric disorders | 8 of 61 | 13 of 59 |
| Injury, poisoning, and procedural complications | Injury, poisoning and procedural complications | 9 of 61 | 5 of 59 |
| Increase in other psychiatric symptoms | Psychiatric disorders | 8 of 61 | 3 of 59 |
| Nervous system disorders | Nervous system disorders | 4 of 61 | 3 of 59 |
| Surgical and medical procedures | Surgical and medical procedures | 2 of 61 | 4 of 59 |
| Suicidal ideation and/or self-harm | Psychiatric disorders | 4 of 61 | 1 of 59 |
| Respiratory, thoracic and mediastinal disorders | Respiratory, thoracic and mediastinal disorders | 2 of 61 | 3 of 59 |
| Social circumstances | Social circumstances | 2 of 61 | 3 of 59 |
Serious events with the highest arm-level rate: suicidal ideation (1.7%), mononucleosis (1.7%), anaphylactic shock (1.7%), increase in bdd and depressive symptoms (1.6%), self-harm (1.6%).
The registry reports serious adverse events for each treatment group: CBT had 5 serious adverse events among 61 at risk, and SPT had 3 among 59 at risk. It reports other adverse events separately: CBT had 34 among 61 at risk, and SPT had 30 among 59 at risk. Deaths are recorded as 0 in each group.
The listed serious-event terms and percentages are suicidal ideation, 1.7%; mononucleosis, 1.7%; anaphylactic shock, 1.7%; increase in BDD and depressive Symptoms, 1.6%; self-harm, 1.6%; and negative reaction to anesthesia, 1.6%. These are terms and percentages as recorded. The registry record does not explain how the percentages were calculated or whether the listed terms account for all serious events.
These figures are descriptive counts, not proof that an intervention caused an event. The record does not report event-level timing, severity beyond the serious-event classification, relatedness assessments, or statistical comparisons between groups. It also does not state whether participants could contribute more than one event. The counts should therefore be read as safety information recorded for the trial, not as a causal comparison or a complete account of individual participants’ experiences.
12. What the Result Does, and Does Not, Mean
The registry record establishes that a randomized, parallel-group study compared CBT with SPT for BDD and identified BDD-YBOCS change as its primary outcome. It also specifies separate treatment and follow-up analysis periods and lists secondary measures spanning several symptom and functioning domains. Those details make the study question and measurement framework understandable.
They do not, by themselves, establish which treatment had a larger average improvement, whether any difference was statistically distinguishable from chance, or how precisely a difference was estimated. The registry record does not report numerical primary-outcome estimates, treatment contrasts, confidence intervals, or test results. It also does not report results for the listed secondary outcomes. A direction or magnitude of treatment effect should not be inferred from the design description alone.
The scale’s scoring direction provides a way to interpret any reported score: higher BDD-YBOCS scores indicate more severe symptoms. However, the actual scores and changes are absent from the registry record. Similarly, the fact that outcome assessments were scheduled across treatment and follow-up does not show whether a pattern continued after treatment; the follow-up results are not reported.
The safety counts document reported serious and other adverse events, but they do not establish causation or the comparative likelihood of events. The registry does not give enough detail to determine whether events overlapped within individuals or how investigators assessed their relationship to treatment. Zero deaths are recorded in both groups, but that observation alone does not characterize all aspects of safety.
The study’s design can frame a randomized comparison, but interpretation also depends on the analysis methods, missing data, adherence, and the precision of estimates. Those details are incomplete in the record. Accordingly, the posted information supports a careful account of what was measured and what events were recorded, while leaving the central comparative outcome question unresolved.
13. Why This Trial Matters Statistically
This trial is statistically notable for framing a direct randomized comparison of two psychotherapies for BDD and specifying a symptom measure tailored to the disorder. The primary measure is clinician-administered, has a defined score range, and has a clear direction: higher scores indicate more severe symptoms. These features help readers understand what the outcome represents without treating the score as a complete account of a participant’s condition.
The record also distinguishes treatment-period change from follow-up-period change. That distinction is important because an average trajectory while treatment is underway and a trajectory during follow-up address different time frames. Reporting separate analyses makes the intended questions clearer, although the numerical results needed to evaluate those questions are not reported in the registry record.
The study lists multiple outcome measures and analyses, which makes transparency about analysis selection, multiplicity, and missing data important. The registry record identifies the counts and names a range of secondary measures, but does not describe adjustment for multiple testing, the model for repeated assessments, or methods for handling missing observations. Those details affect how confidently estimates can be interpreted and compared.
Finally, the record illustrates the difference between a trial’s design information and its results. Randomization, enrollment, endpoint definitions, and safety counts help describe the study, but they cannot substitute for group estimates and uncertainty intervals. In this record, the statistical question is identifiable, while the primary comparative findings and key analysis details are not reported. That gap limits what can be concluded from the registry entry.
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 most direct limitation for interpreting this trial from the registry record is the absence of numerical primary-outcome findings. Group means, standard deviations, changes, between-group contrasts, confidence intervals, and significance tests are not reported. The primary outcome includes several assessment times and separate treatment and follow-up periods, but the record does not provide the corresponding trajectories or a single contrast that would allow their magnitude and precision to be assessed.
Details needed to evaluate the analysis are also absent. The record does not state the statistical model, how repeated measures were handled, how missing assessments were addressed, or the exact numbers contributing to each analysis. It notes cancellations and dropouts but does not quantify their extent or describe sensitivity analyses. The term intent-to-treat is used, but the registry does not specify the operational approach to missing outcomes.
The masking designation is single, but who was masked and how masking was maintained are not reported in the registry record. Details of random-sequence generation, allocation concealment, treatment content, treatment exposure, and fidelity are also not reported. The entry does not give participant eligibility criteria or baseline characteristics, which limits assessment of the enrolled population and comparability on measured characteristics.
The record lists several outcomes and analyses but does not describe a multiplicity strategy or identify a complete statistical analysis plan. It also does not report a sample-size justification for the trial. Safety counts are given, but event timing, relatedness, participant-level overlap, and comparative analyses are not reported. These gaps do not prove that the trial’s conduct or analyses were deficient; they limit what can be established from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Cognitive-Behavioral Therapy and Supportive Psychotherapy for Body Dysmorphic Disorder — NCT01453439.
- Registry record last updated 2020-07-15; status last verified 2020-07.
- Results first posted 2020-07-15.
- 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
NCT01453439 is a completed randomized, parallel-group trial sponsored by Massachusetts General Hospital, comparing Cognitive Behavioral Therapy with Supportive Psychotherapy for body dysmorphic disorder. The registry lists enrollment of 120 and single masking, but does not specify who was masked. The primary outcome was change in BDD-YBOCS symptom severity, analyzed separately for treatment and follow-up periods.
The record describes secondary outcomes across symptom, belief, functioning, and life-satisfaction domains, and lists safety counts for serious and other adverse events. It does not report numerical primary or secondary outcome findings, confidence intervals, the statistical model, or methods for handling missing assessments. The available record therefore describes the question, design, measures, and some safety information, but not the quantitative treatment comparison.