Behavioral Activation Intervention, Reward Processing, and Youth Smoking Cessation: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Behavioral Activation Intervention, Reward Processing, and Youth Smoking Cessation (NCT01351766), a na phase 3 study. The primary outcome is Number of Participants Smoking-Abstinent for 7 Days, 12 Weeks Post Quit Date.

2. Clinical Question

3. Trial Design

The registry record describes a Phase 3 study of behavioral activation for smoking in youths ages 18-21 with elevated depressive symptoms. Its stated purpose was to develop a specialized behavioral activation treatment for this population. The description separates the work into a development phase and a subsequent open-label trial. The development phase used focus groups and pilot testing with 15 youths. Overall enrollment is listed as 39, but the number enrolled in each phase is not reported in the registry record.

The intervention group is named Behavioral Activation for Smoking. The regimen is described as eight 60-minute group sessions over an eight-week period, together with eight weeks of transdermal nicotine patch beginning at the time of quitting and continuing after treatment sessions ended. The patch dose is not fully specified in the registry record. Participants were to be followed over 26 weeks after the quit date. A subset was also to undergo an fMRI session to examine reward sensitivity; the size of that subset and its results are not reported in the registry record.

The study is listed as single group, with allocation not applicable and no masking. It is therefore not a randomized comparison, and the group cannot serve as a concurrent control for itself. The record lists smoking as the condition and transdermal nicotine patch as the intervention. It marks the study completed, with a start of 2010-04 and primary completion of 2013-05.

The record does not report a detailed statistical analysis plan, a sample-size justification, or interim analyses. In particular, it does not establish how the proposed development work and open-label trial contributed to the total enrollment or to the primary endpoint analysis. These design details matter when interpreting the posted endpoint and any descriptive material accompanying it.

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.

Overall Study

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.

Population: Analysis population is not different from the assignment in Participant Flow.

6. Primary Endpoint

The registry lists the primary outcome as Number of Participants Smoking-Abstinent for 7 Days, 12 Weeks Post Quit Date, measured over 12 weeks post quit date.

The primary endpoint is a count of participants with seven days of smoking abstinence at 12 weeks after the quit date. Abstinence was to be confirmed using expired carbon monoxide. The endpoint combines a defined duration without smoking, a specified assessment time, and an objective confirmation method. These features make the outcome more operational than an unverified report of smoking status, although the registry record does not describe the carbon monoxide threshold, the assessment procedures, or how missing assessments were handled.

A binary endpoint such as this classifies each participant as meeting or not meeting the abstinence definition at the stated assessment. A count can summarize how many participants met the definition, while an estimated proportion and its uncertainty could describe the result relative to the number assessed. The registry record does not report the endpoint count, denominator used for the analysis, estimated proportion, or confidence interval, so those quantities cannot be interpreted.

The endpoint focuses on abstinence at one follow-up time, not on the full course of smoking behavior across the 26 weeks of planned follow-up. It also does not itself measure reward processing, depressive symptoms, or the effect of behavioral activation apart from the nicotine patch and other study components. The registry record does not report results for those other measures.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The statistical information in this record is limited. It identifies a single-group study, an endpoint expressed as a participant count, and an abstinence definition at a specified follow-up time. It does not report the primary endpoint result or an analysis. The explanations below describe general statistical concepts; they do not imply that a particular method was used in this study unless the registry record says so.

What does a count endpoint represent?

A count of participants meeting a binary definition is the number classified as having the event of interest. Here, the event is meeting the seven-day abstinence definition at 12 weeks post quit date, with confirmation via expired carbon monoxide. A count is meaningful alongside the number of participants assessed. The count alone does not say what share of the group met the definition, and a denominator that excludes participants without an assessment can differ from one that includes all enrolled participants.

In general, a binary outcome may also be summarized as a proportion, with a confidence interval to show uncertainty around the estimate. A confidence interval is a range of values compatible with the observed data under the statistical model and method used. Its width reflects the amount of information and the analysis approach. No endpoint proportion or confidence interval is reported in the registry record, so there is no precision estimate to interpret.

Why does the study structure matter?

In a randomized comparison, an analysis can compare outcomes across assigned groups, subject to the design and assumptions. This record describes a single group, with allocation not applicable and no masking. There is no control-group contrast to estimate. A within-group description can summarize the endpoint among participants, but it cannot isolate the intervention's effect from other explanations for the observed outcome. This is a design limitation, not a matter that a more complex statistical model can resolve after the fact.

The intervention is described as a behavioral activation program alongside an eight-week nicotine patch regimen. If an endpoint result were available, it would pertain to the study's combined treatment context; the record does not describe a design that separates the effects of the group sessions and the patch. It also does not report whether analyses considered additional variables or how such analyses, if any, were specified.

What does uncertainty depend on?

For a binary outcome, uncertainty depends in part on the number of participants with outcome information and on how many meet the endpoint definition. Missing endpoint assessments complicate interpretation because the observed participants may not represent everyone enrolled. General approaches include defining an analysis population in advance, describing missingness, and using an appropriate sensitivity analysis. The registry record does not report the endpoint denominator, missing-data method, or sensitivity analyses, so it is not possible to determine how these issues were addressed.

The registry lists enrollment of 39, but this does not establish the number analyzed at 12 weeks. Nor does the record provide a sample-size justification or an account of the precision anticipated for the primary endpoint. The design description refers to focus groups and pilot testing with 15 youths, but does not clarify how that group relates to the overall enrollment or the endpoint analysis population.

How should planning illustrations be read?

Sample-size calculations are planning tools, not observed evidence about a treatment. The planning assumptions described for the page use a two-sided significance level of 0.05, equal allocation between two arms, a normal approximation, and a target effect expressed as a stated fraction of an observed effect. These are assumptions for an illustration, not a description of this study's single-group allocation. The registry record does not report that these assumptions were used to design the trial or justify its enrollment.

Participants-per-arm figures based on such assumptions are hypothetical planning quantities. They do not show the probability that this completed study detected an effect, and they are not observed power. The record does not report the observed effect needed to judge such an illustration, nor does it report a treatment contrast from a randomized comparison. Any planning display should therefore be kept separate from the study's design and outcome evidence.

What analyses are documented?

The record lists one outcome measure and zero analyses. It does not state a model, a significance test, a confidence-interval method, an adjustment strategy, or an interim-analysis plan. For an endpoint count, a simple descriptive summary might be appropriate, but the registry record does not say what analysis was performed. No inferential result should be inferred solely from the endpoint's presence in the record or from the study's completed status.

Overall, the statistical record supports describing the planned endpoint and recognizing the single-group design. It does not support quantifying the endpoint result, precision, or comparative effect. Those are distinct from general statistical explanations and would require results and analysis details not reported in the registry record.

10. Exact Estimates for Each Arm

No two-arm comparison is shown for this trial, but each arm's result can still be summarized with exact interval estimates computed from the posted counts. The Clopper-Pearson interval is exact and conservative; the Wilson interval is a common closer-to-nominal alternative; the Bayesian credible interval uses a uniform Beta(1, 1) prior. For small groups the three can differ noticeably.

R code and output

arm    <- c("Behavioral Activation for Smoking")
n      <- c(39)
events <- c(7)
for (i in seq_along(n)) {
  ci <- binom.test(events[i], n[i])$conf.int          # Clopper-Pearson exact interval
  cr <- qbeta(c(0.025, 0.975), 1 + events[i], 1 + n[i] - events[i])   # Bayesian, uniform Beta(1,1) prior
  wi <- (function(x, n) { p <- x / n; z <- qnorm(0.975); d <- 1 + z^2 / n
    c((p + z^2 / (2 * n) - z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d, (p + z^2 / (2 * n) + z * sqrt(p * (1 - p) / n + z^2 / (4 * n^2))) / d) })(events[i], n[i])
  cat(sprintf("ARM|%s|%d|%d|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f|%.1f\n", arm[i], n[i], events[i], 100 * events[i] / n[i],
              100 * ci[1], 100 * ci[2], 100 * wi[1], 100 * wi[2], 100 * cr[1], 100 * cr[2]))
}

ARM  Behavioral Activation for Smoking  39  7  17.9  7.5  33.5  9.0  32.7  9.1  32.8

11. Multiplicity, Missing Data and Analysis Populations

The registry record lists one outcome measure, the count of participants smoking-abstinent for seven days at 12 weeks post quit date. It lists zero analyses. It does not report whether there were additional outcomes that were analyzed but not listed, whether the primary endpoint was selected from a larger set, or whether any multiplicity adjustment was planned. A multiplicity strategy is therefore not reported in the registry record.

The study description also mentions follow-up over 26 weeks and an fMRI session for a subset of participants. These descriptions do not establish which additional outcomes were analyzed, when they were assessed, or how they relate to the primary endpoint. Results for those measures are not reported in the registry record. The single listed outcome should not be taken to mean that no other measurements were collected.

Missing-data handling is also not reported. The record does not state the number with an endpoint assessment, the analysis population, the number missing, reasons for missingness, or how participants without a 12-week assessment were classified. It does not describe imputation or sensitivity analyses. These details affect both the denominator and the interpretation of a binary count.

The record does not describe an intention-to-treat or per-protocol analysis population. Because there is no randomized comparison, a treatment-assignment analysis is not outlined; nevertheless, the population used to summarize outcomes still matters. Without these definitions, the reader cannot tell whether any endpoint result represents all enrolled participants or a subset with available assessments.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The posted safety figures list 39 participants at risk in the Behavioral Activation for Smoking group. They show 0 serious adverse events, 0 other adverse events, and 0 deaths. These figures describe the counts recorded in this group; they are not a comparison with an untreated or alternative-treatment group, because the study is single group.

A zero count means that no events of the relevant type appear in the posted figures. It does not establish that the intervention carries no risk, and it does not describe the chance of an event with high precision in a group of this size. In general, safety counts should be considered alongside the number observed, the duration and completeness of follow-up, event definitions, and how events were collected. The registry record does not report detailed safety-collection procedures or event definitions beyond the serious and other categories.

The record does not list serious adverse-event terms. The safety figures should not be interpreted as evidence that no symptoms or non-serious experiences occurred outside the categories displayed. They are counts as posted, not a complete account of every possible safety outcome.

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

This record establishes that a completed, single-group study was conducted to develop and examine a behavioral activation approach for smoking in youths ages 18-21 with elevated depressive symptoms. The intervention description includes group sessions and transdermal nicotine patch, and the primary endpoint is clearly framed around seven days of abstinence at 12 weeks after the quit date, confirmed via expired carbon monoxide. The record also gives overall enrollment as 39 and describes follow-up over 26 weeks.

What the record does not establish is the observed abstinence result. It does not state how many participants met the primary endpoint, how many were assessed, or the uncertainty around an estimate. Without those results, it is not possible to quantify the endpoint from the registry record. There is also no randomized comparator, so the study design cannot separate changes associated with the program from other possible explanations or estimate a comparative treatment effect.

The stated endpoint is a snapshot at one follow-up time, based on a seven-day abstinence period. It is not by itself evidence about continuous abstinence throughout follow-up, long-term smoking behavior, or reward processing. Although the summary mentions an fMRI session for a subset, the subset size and findings are not reported in the registry record. The record likewise does not report results for other measures or details of the analysis population.

These limits do not negate the descriptive purpose of a development and open-label study. They define what can be concluded from the registry information: the study's setting, intervention description, design, and intended primary measure can be described, but the clinical outcome cannot be quantified from this record. Any interpretation of results beyond those details would require endpoint results, denominators, and analysis information not reported in the registry record.

14. Why This Trial Matters Statistically

This trial is statistically instructive because its primary outcome is easy to state but still requires careful interpretation. A binary abstinence definition can be summarized as a participant count, but that count needs a clear denominator and an account of participants whose status is unknown. The registry record names the outcome and assessment time, yet does not report the observed count or analysis population. This illustrates why endpoint definitions and endpoint results are separate pieces of evidence.

The single-group structure is equally important. A within-group endpoint can describe participants' observed status, but a comparative treatment effect requires a meaningful comparison. Here, the registry record identifies no randomized control group. The intervention also combines behavioral activation sessions with nicotine patch, so an outcome for the group would not isolate the contribution of either component.

The record's development and open-label description also helps distinguish feasibility or intervention development from confirmatory comparative evidence. It describes focus groups and pilot testing with 15 youths, followed by a planned open-label trial, but does not report the number in each phase or how the primary endpoint analysis was carried out. Those omissions limit assessment of how the study's different aims relate to the total enrollment.

Finally, this record shows why a completed status and a defined primary outcome are not substitutes for statistical results. Without the endpoint count, denominator, uncertainty estimate, and analysis details, readers cannot judge the magnitude or precision of the outcome. Statistical interpretation depends not just on a study's label or its planned measure, but on the results and design information needed to connect observations to a well-defined question.

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.

The principal limitation is that the registry record does not report the primary endpoint result. It provides the endpoint definition but not the number of participants abstinent, the number assessed, or an estimate with uncertainty. That prevents quantitative interpretation of the primary outcome.

The single-group, open-label design has no randomized comparator. Any descriptive endpoint result would therefore lack a concurrent control-group contrast. The record does not describe a design that separates behavioral activation from transdermal nicotine patch, which was part of the intervention regimen. Causal attribution to either component is consequently not supported by the design information recorded.

Several implementation and analysis details are incomplete. The patch-dose description is cut off, the size of the fMRI subset is not reported, and the record does not specify how many participants belonged to each described phase. It also does not report the endpoint analysis population, missing-data handling, or the methods used for statistical analysis. The stated overall enrollment of 39 does not establish how many participants contributed to the 12-week endpoint.

The primary endpoint covers seven days of abstinence at one assessment time. Although follow-up over 26 weeks is described, the registry record does not report longer-term outcome results or establish that the primary endpoint reflects smoking behavior across the full follow-up. It also does not report results for reward processing or other measures. These limitations are specific to what this record documents and should be considered alongside any results available elsewhere.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Behavioral Activation Intervention, Reward Processing, and Youth Smoking Cessation — NCT01351766.
• Registry record last updated 2022-05-18; status last verified 2022-05.
• Results first posted 2020-12-02.
• 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

The registry record describes NCT01351766, a completed Phase 3, single-group study of behavioral activation for smoking in youths ages 18-21 with elevated depressive symptoms. Overall enrollment was 39. The intervention description includes eight 60-minute group sessions over eight weeks and eight weeks of transdermal nicotine patch beginning at the quit date; the dose detail is incomplete.

The primary endpoint is the count of participants with seven days of smoking abstinence at 12 weeks post quit date, confirmed via expired carbon monoxide. The record does not report the endpoint count, an analysis, or a statistical analysis plan. It lists 0 serious adverse events, 0 other adverse events, and 0 deaths among 39 participants at risk in the intervention group. With no randomized comparator and no reported endpoint result, the record supports describing the study and its intended measure but not estimating a comparative effect.