Cognitive-Behavioral Therapy and Escitalopram for Generalized Anxiety Disorder(GAD): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Cognitive-Behavioral Therapy and Escitalopram for Generalized Anxiety Disorder(GAD) (NCT00219349), a na phase 4 study. The primary outcome is Change in Hamilton Anxiety Rating Scale Score.

2. Clinical Question

The study was intended as a pilot investigation of a staged treatment approach for generalized anxiety disorder. Its stated goals included examining cognitive-behavioral therapy, adding antidepressant therapy for participants who did not fully respond to therapy, and exploring individual and clinical predictors of response. The brief summary also describes a goal of examining maintenance of treatment gains over a twenty-four month follow-up period.

The primary outcome addresses change in anxiety severity during the period identified as week 14 to week 26. It is not a comparison of two randomized groups: the registry lists a single-group model and does not report a like-for-like control arm. The primary outcome population is narrower than the overall enrollment, since it refers specifically to participants who completed the cognitive-behavioral therapy phase and started escitalopram. The number of participants in that outcome population is not reported in the registry record.

The brief summary states hypotheses about remission, functioning, and further improvement after augmentation. Those statements describe expectations for the investigation, not observed findings. Numerical results for the primary question are not reported in the registry record.

3. Trial Design

This completed phase 4 pilot study was sponsored by the New York State Psychiatric Institute. The registry lists a start date of 2005-01, primary completion of 2008-07, and total enrollment of 25. Its design is identified as single-group; allocation is NA and masking is none. The registry therefore does not describe a randomized, masked comparison between treatment arms.

The treatment approach combined cognitive-behavioral therapy with possible antidepressant augmentation. The registry describes an Escitalopram group receiving 12 weeks of open-label escitalopram, 10-20 mg/day, after 14 weeks of cognitive-behavioral therapy. The primary-outcome description identifies the relevant participants as those who completed the cognitive-behavioral therapy phase and started escitalopram. The number who reached that stage is not reported in the registry record.

The brief summary frames the work as a pilot investigation intended to inform preparation for a larger federally funded study. It describes goals of examining the psychotherapy, augmentation for participants who did not fully respond, predictors of response or non-response, and maintenance of treatment gains over a twenty-four month follow-up period. These are stated aims; the registry record does not report whether each aim was completed or what results were observed.

The registry lists the primary outcome as change in Hamilton Anxiety Rating Scale score from week 14 to week 26. It also names secondary outcomes concerning the Clinical Global Impressions-Improvement Index and changes in depression ratings. The record lists eight outcome measures in total, but it does not provide numerical outcome estimates or a description of the analysis methods. A completed status indicates the study's recorded status, not that every planned outcome or analysis is reported.

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.

Cognitive Behavioral Therapy Phase

Reasons for not completing this period:

Escitalopram Phase

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: see above: Patients who completed the CBT phase and started escitalopram treatment

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.

6. Primary Endpoint

The registry lists the primary outcome as Change in Hamilton Anxiety Rating Scale Score, measured over week 14 to week 26.

The primary endpoint is change in Hamilton Anxiety Rating Scale score from week 14 to week 26. The scale is clinician-administered and assesses anxiety severity from 0 (low) to 64 (high). The registry states that a greater magnitude of decrease during treatment represents greater improvement in anxiety. The outcome is described as a mean, with standard deviation as its measure of dispersion, and is expressed in units on a scale.

This endpoint is relevant to the study's stated aim of assessing anxiety change during the escitalopram augmentation phase after cognitive-behavioral therapy. The named population consists of participants who completed the cognitive-behavioral therapy phase and started escitalopram, rather than necessarily all 25 enrolled participants. The count in that population and the actual mean change are not reported in the registry record.

In general, a mean change conveys the average direction and magnitude of change in the measured scale for the analyzed group. A standard deviation describes how dispersed individual measurements are around the mean; it is not itself a measure of uncertainty in the estimated mean. Without the numerical mean, dispersion, and analysis details, the registry record does not establish the size or precision of the observed change.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry classifies the primary outcome as continuous and describes it as a mean with standard deviation. These terms indicate the intended summary format, but they do not supply the actual outcome estimate. The numerical mean change and its standard deviation are not reported in the registry record, nor are a confidence interval or hypothesis-test result.

What does a mean change describe?

In general, a mean change summarizes the average difference between measurements at the stated time points for the participants included in an analysis. For this study, the specified interval is week 14 to week 26, and the measure is the Hamilton Anxiety Rating Scale. The registry says that greater decrease corresponds to greater improvement. The mean alone would not show whether every participant changed in the same direction; participants' changes can vary around the average.

In general, a standard deviation describes the spread of individual measurements around a mean. It is different from a standard error, which concerns the precision of an estimated mean, and from a confidence interval, which expresses uncertainty around an estimate under a specified method. The record identifies standard deviation as the dispersion measure but does not report a value. It also does not describe a method for estimating uncertainty around the mean change.

What can a single-group design establish?

The registry identifies a single-group model, no masking, and allocation listed as NA. In general, within-group change can describe what happened between measurements among participants with available data. Without a concurrent randomized control group, such change does not separate the effect of a particular treatment component from other influences. This matters especially in a staged approach: the primary outcome period follows cognitive-behavioral therapy and concerns participants who completed that phase and started escitalopram. The record does not describe a comparison that would isolate the contribution of augmentation.

The open-label description means the escitalopram phase was not masked according to the registry. In general, lack of masking can affect participant or clinician expectations and can influence subjective ratings or reporting. The Hamilton scale is clinician-administered, as the record states. The registry does not report procedures used to limit possible measurement or expectation effects, so no such procedures should be assumed.

What do planning assumptions mean?

The registry describes a sample-size planning illustration based on the observed effect, rather than the trial's own design. Its stated assumptions include a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. The registry's general note distinguishes participant counts per arm for non-time-to-event outcomes from total event counts for time-to-event outcomes.

These assumptions describe a hypothetical planning framework; they do not turn this single-group pilot into a two-arm randomized trial. In general, a sample-size calculation estimates the number of participants needed under chosen assumptions for a planned future comparison. It is not a measure of the probability that this completed study found a real effect, and it is not observed power. The record does not report the numerical observed effect used for the illustration or the numerical planning results in the registry record for this analysis. No sample-size justification for the trial itself is reported in the registry record.

What statistical analyses are reported?

The registry lists zero analyses. It does not report the test or model used for the primary outcome, whether the estimate was adjusted for other variables, how repeated measurements were handled, or how uncertainty was quantified. It also does not report a prespecified decision threshold for interpreting the primary outcome. Those omissions mean that the intended descriptive summary can be identified, but its analysis cannot be reproduced or assessed from the registry record.

In general, a confidence interval communicates a range of values compatible with an estimate under the method's assumptions and gives information about precision. A p-value, when used, summarizes how unusual data at least as extreme as those observed would be under a specified null model; it does not measure clinical importance. Neither type of result can be interpreted for this endpoint because numerical estimates and inferential results are not reported in the registry record.

Over-dispersion is a general concern when observed variability is greater than a statistical model assumes. If a model understates variability, its uncertainty estimates can be too narrow. The registry does not identify a model for the primary endpoint or report a dispersion assessment, so it is not possible to determine whether this issue arose or how it was handled. This is a general methodological consideration, not a finding about this study.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Patients Who Started Escitalopram")
n   <- c(7)
m   <- c(-6.4)
sp  <- c(10.1)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Patients Who Started Escitalopram  7  -6.400  10.100  -15.741  2.941

11. Multiplicity, Missing Data and Analysis Populations

The registry lists eight outcome measures, including the primary change in Hamilton Anxiety Rating Scale score and secondary outcomes involving the Clinical Global Impressions-Improvement Index and depression measures. It lists zero analyses. A statistical procedure for controlling multiplicity, such as adjusting interpretation across multiple outcome tests, is not reported in the registry record. The record also does not state whether any outcomes were designated as exploratory or whether an outcome hierarchy was used.

In general, testing or emphasizing multiple outcomes can increase the chance that some results appear notable by chance. A prespecified hierarchy or adjustment can help make interpretation more transparent. Since no analysis results or multiplicity strategy are reported, the available record does not allow assessment of how the several outcomes were analyzed together. No result should be selected as the study's strongest finding on the basis of this record.

The primary-outcome population is described as participants who completed cognitive-behavioral therapy and started escitalopram. The count reaching that stage is not reported in the registry record. The number with a week 26 measurement, the analysis population definition, and whether all enrolled participants were included in any outcome analysis are also not reported.

Missing-data methods are not reported in the registry record. In general, missing outcome measurements can affect estimates if participants with missing data differ from those with observed data. Approaches such as imputation or model-based analysis require assumptions about missingness and the data structure; none should be attributed to this study without documentation. The record also does not describe whether participants who stopped treatment, did not complete follow-up, or did not start augmentation were included in any analysis. These reporting gaps limit both reproducibility and the assessment of potential selection effects.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports safety counts for Group 1. For serious adverse events, 25 participants were listed as at risk and 0 as affected. For other adverse events, 25 were listed as at risk and 2 as affected. These are counts, not rates calculated for a follow-up period, and the record does not provide event descriptions for the other adverse events.

No serious adverse-event terms are listed. Deaths are not reported in the registry record. The absence of listed serious-event terms should be read as a feature of the registry entry, not as proof that no event of any kind occurred or that every safety detail is available. The record does not explain the observation window, event collection procedures, severity criteria, or whether the counts cover the entire study or a defined treatment phase.

The safety counts do not establish comparative risk because the study is identified as single-group and no control group is reported. The number at risk is the registry's denominator for these entries; it should not be assumed to describe exposure duration or complete follow-up. These figures are limited to the adverse-event information recorded in the registry and cannot be treated as a comprehensive safety assessment.

13. What the Result Does, and Does Not, Mean

The registry record establishes that a completed pilot study enrolled 25 participants and examined a staged approach involving cognitive-behavioral therapy and open-label escitalopram. It identifies change in Hamilton Anxiety Rating Scale score from week 14 to week 26 as the primary outcome for participants who completed the cognitive-behavioral therapy phase and started escitalopram. It also records limited adverse-event counts.

The record does not establish the magnitude or precision of anxiety-score change. It does not report the mean change, its standard deviation, confidence interval, or statistical test result. The brief summary's predicted remission or improvement is a hypothesis, not an observed result. Accordingly, the registry entry cannot support a conclusion that the treatment approach did or did not produce a particular outcome.

Even if within-group changes were reported, a single-group design would not by itself establish that escitalopram caused the change. The primary outcome period follows cognitive-behavioral therapy, and the record does not describe a randomized control group or an analysis that separates the effects of the treatment stages. It also does not report the number of participants who entered the augmentation phase or the handling of missing endpoint measurements.

The pilot framing matters: the stated purpose included investigating a treatment approach in preparation for a larger study. Pilot objectives can include testing procedures and exploring possible patterns, not only estimating treatment effects. The registry record does not report protocol feasibility results or a sample-size justification, so those aspects cannot be evaluated.

The appropriate reading is therefore narrow. The entry describes the design, treatment sequence, endpoint, and selected safety counts, but does not provide the outcome analyses needed to quantify treatment-period change. The stated aims and hypotheses should remain distinct from findings, and the absence of a reported estimate should not be taken as evidence either for or against an effect.

14. Why This Trial Matters Statistically

This study illustrates why a treatment description and a completed status are not substitutes for statistical results. The registry gives a primary measure, an assessment interval, a target population, and a summary format, but does not report the mean change or its uncertainty. Without those results, readers cannot judge the magnitude, precision, or consistency of the primary outcome.

It also highlights the importance of matching the estimand to the design. The primary outcome applies to participants who completed cognitive-behavioral therapy and started escitalopram, while total enrollment was 25. The number reaching that treatment stage is not reported. That distinction affects how broadly a result could apply, even if numerical results were available.

The single-group structure is another central statistical feature. A before-and-after description can be useful in a pilot, but it does not supply the same causal contrast as a randomized comparison. The stated sample-size illustration assumes equal allocation between two arms, while the registry describes a single-group study. Keeping planning assumptions distinct from the actual trial design prevents a hypothetical calculation from being mistaken for evidence from the enrolled participants.

Finally, the record shows why transparent reporting of analysis populations, missing-data handling, multiplicity, and uncertainty matters. Those details are not reported, and the listed outcome measures are not accompanied by analyses. The study can be understood as a pilot with a defined clinical question, but its statistical findings cannot be independently interpreted from the registry entry.

15. 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.

Several limitations are specific to the information reported for this study. The primary outcome is defined for participants who completed cognitive-behavioral therapy and started escitalopram, but the number in this group is not reported in the registry record. The entry also does not state how many completed the week 26 assessment. As a result, the size and completeness of the primary-outcome population cannot be assessed against the total enrollment of 25.

The design is single-group, with no masking and no reported randomized comparator. The endpoint interval follows the cognitive-behavioral therapy phase and concerns the augmentation stage, so a change over that interval would not by itself separate the effects of escitalopram from other influences or identify what would have happened without augmentation. The record does not report a comparison or adjustment that addresses this issue.

Numerical primary and secondary outcome findings are not reported in the registry record. The analysis methods, uncertainty estimates, missing-data procedures, analysis populations, and multiplicity strategy are also not reported. These gaps prevent assessment of precision, reproducibility, and the robustness of any estimated change.

The brief summary describes a goal of examining maintenance over a twenty-four month follow-up period, but follow-up findings are not reported in the registry record. The stated pilot purpose and hypotheses do not establish the outcome of the study. The planning assumptions described for a two-arm sample-size illustration are not a justification for the single-group trial's enrollment. These limitations concern what can be concluded from the registry entry; they do not determine what may have been reported elsewhere.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Cognitive-Behavioral Therapy and Escitalopram for Generalized Anxiety Disorder(GAD) — NCT00219349.
• Registry record last updated 2017-12-19; status last verified 2017-11.
• Results first posted 2012-05-09.
• 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.

19. Record Summary

NCT00219349 is a completed phase 4, single-group pilot study sponsored by the New York State Psychiatric Institute. The registry lists enrollment of 25, a start date of 2005-01, and primary completion of 2008-07. Masking is listed as none, and allocation as NA.

The treatment approach included cognitive-behavioral therapy followed by open-label escitalopram. The registry describes 12 weeks of escitalopram at 10-20 mg/day after 14 weeks of cognitive-behavioral therapy. The primary outcome is change in Hamilton Anxiety Rating Scale score from week 14 to week 26 among participants who completed the therapy phase and started escitalopram.

The record lists eight outcome measures and zero analyses. It does not report numerical outcome estimates, statistical analysis methods, missing-data procedures, or a multiplicity strategy. Serious adverse events are listed as 0 affected among 25 at risk; other adverse events are listed as 2 affected among 25 at risk. Deaths are not reported in the registry record.