Effect of Oxytocin on Craving and Therapy Response: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effect of Oxytocin on Craving and Therapy Response (NCT01827332), a randomized na study. The primary outcome is Therapy Session Satisfaction (as Measured by Subjective Report).

2. Clinical Question

The trial asks whether therapy-session satisfaction, measured after Motivational Enhancement Therapy (MET), differs between participants assigned to intranasal oxytocin and those assigned to intranasal saline. The registry describes the study as examining oxytocin’s impact on marijuana use and therapy response in people who frequently use marijuana. The primary result posted is a subjective rating of the last MET session, rather than a direct measure of marijuana use.

The posted arm means are 9.8 for oxytocin and 9.7 for saline, on a scale ranging from 0, most dissatisfied, to 10, most satisfied. These descriptive results do not themselves establish whether the arms differ. The registry marks a two-arm comparison for this continuous outcome as missing or not estimable, and it lists no analysis results. Therefore, the central statistical question cannot be answered with a reported inferential comparison in this record.

3. Trial Design

This was a randomized, double-masked, parallel-group study, with oxytocin and saline as the two interventions. Both are described as intranasal administrations. The registry lists the study phase as not applicable. The sponsor is the Medical University of South Carolina. The record lists a start date of 2013-03, primary completion in 2015-06, and study status as completed.

Enrollment is listed as 16. For the primary endpoint, the oxytocin arm has a reported sample size of 6 and the saline arm has a reported sample size of 7. The registry does not explain how those endpoint counts relate to overall enrollment, so the reasons for the differing counts are not reported in the registry record. The adverse-event information uses 8 participants at risk in each arm, a separate set of counts whose relationship to endpoint availability is likewise not explained.

Randomization and double masking describe important features of the design, but the record does not report how the random sequence was generated, whether allocation was concealed, or which groups of people were masked. It also does not describe the intervention dose, treatment schedule, or the amount of MET received. Those details should not be inferred from the design labels.

The registry lists two outcome measures and one secondary outcome, marijuana use measured by subjective report of daily smoking sessions. It does not report a numerical result for that secondary outcome in the registry record for this analysis. The primary endpoint is therapy-session satisfaction at the last MET session. Although the study is marked completed, no analysis results are listed, and no two-arm continuous comparison is estimable in the record. Completion status and the presence of arm-level summaries do not substitute for a reported analysis.

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

Reasons for not completing this period:

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 Therapy Session Satisfaction (as Measured by Subjective Report), measured over Within 5 minutes of completing a 45-60 minute Motivational Enhancement Therapy (MET) session at last session visit.

The primary endpoint is Therapy Session Satisfaction, measured by a subjective report using the Session Rating Scale (SRS). After MET sessions, participants completed the SRS, a visual analog scale with four items covering relationship, goals and topics, approach or method, and overall experience. The reported outcome is the SRS score at the last MET session.

The scale’s minimum score of 0 represents most dissatisfied, and its maximum score of 10 represents most satisfied. The registry reports the endpoint as a mean, with a standard error for each arm. It gives the assessment timing as within 5 minutes of completing a 45-60 minute MET session at the last session visit.

Session satisfaction is used to describe participants’ reported experience of therapy. It is not itself a measure of marijuana consumption, dependence severity, or clinical benefit. A satisfaction score may be relevant to understanding how participants experienced the sessions, but it cannot on its own establish whether therapy response or marijuana use differed. The record does not report a direct relationship between satisfaction scores and the listed secondary outcome of daily smoking sessions.

The outcome is a continuous score, so the arm means summarize average ratings rather than the full spread of individual responses. The reported standard errors describe precision of those estimated means, not the range of experiences among participants. Individual scores and other distributional summaries are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry presents the primary endpoint as a continuous measure and reports an arm-specific mean and standard error. A mean condenses a set of numerical observations into an average. It is useful for describing the central level of a score, but by itself it does not show the shape of the score distribution, whether values are clustered, or whether unusual observations influenced the average.

A standard error describes the sampling uncertainty of an estimated quantity, such as a mean, under the assumptions of the statistical method. It is distinct from a standard deviation, which describes variability among individual observations. The record labels the arm-level dispersion as standard error. It does not provide standard deviations, individual participant scores, or confidence intervals for the means.

A confidence interval is a range of values generated by a statistical procedure to express uncertainty around an estimate. For a treatment comparison, the most directly relevant interval would describe the contrast between arms. The registry does not report such an interval for this endpoint. An interval cannot be substituted by simply reading the two arm-level standard errors separately, because the uncertainty for a contrast depends on the analysis and its assumptions.

A p-value, when reported, quantifies how compatible the observed data are with a specified null model under the chosen test. It is not a measure of clinical importance, and it does not indicate the probability that a treatment works. No p-value or formal test result is listed for the primary endpoint. The record specifically says the two-arm comparison for this continuous endpoint is missing or not estimable, so the descriptive means should not be presented as though a test had been completed.

What does the reported standard error tell the reader?

It gives information about the precision of each estimated arm mean under the relevant statistical assumptions. It does not convey the range of participant-level ratings or the uncertainty in a treatment contrast by itself. The small endpoint counts make it especially important not to treat the displayed means as precise descriptions of every participant’s experience. No further distributional detail is reported.

Why is an estimable comparison important?

Randomized trials are designed to compare outcomes between assigned groups, but an arm-by-arm summary is not the same as an analysis of the randomized contrast. A comparison would ordinarily quantify the difference in outcome between arms and its uncertainty, using a stated method. Here, the registry does not provide that estimate or its inferential summary. The reason the comparison is unavailable is not reported in the registry record.

How should planning calculations be understood?

The registry describes a planning-illustration framework based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation. Such calculations are planning illustrations, not observed trial results and not observed power. They depend on the effect size selected for planning and on statistical assumptions. The stated assumptions do not show that those choices were part of the trial’s original design; the sample-size justification and original planning procedure are not reported in the registry record.

For a continuous endpoint, planning calculations can illustrate how many participants per arm might be needed under an assumed effect and analysis framework. Such an illustration does not establish that a trial with that enrollment would have detected an effect, and it does not change the uncertainty in results already observed. The registry’s comparison is marked not estimable, and no treatment contrast is reported from which to interpret an observed effect in this analysis. No numerical planning result is available in the registry record used for this description.

What can be concluded from the available analysis information?

The record reports arm-level means and standard errors, but zero analyses and no estimable two-arm comparison for the primary continuous outcome. This means the appropriate statistical reading is descriptive. It is not possible to assess from this record whether a prespecified model was used, whether any adjustment was made, whether assumptions were checked, or how missing observations were handled. Each of those analysis details is not reported in the registry record.

General statistical interpretation also depends on the endpoint definition and timing. Here the SRS score refers to the last MET session, assessed within 5 minutes after completing a session described as 45-60 minutes long. This defines a specific subjective measurement occasion; it does not imply that scores were collected at every session for the reported endpoint or that a change from baseline was analyzed. Such analyses are not reported.

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("Oxytocin", "Saline")
n   <- c(6, 7)
m   <- c(9.8, 9.7)
sp  <- c(0.4, 0.3)
sd  <- sp * sqrt(n)      # standard errors converted to SDs
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  Oxytocin  6  9.800  0.980  8.772  10.828
CARM  Saline  7  9.700  0.794  8.966  10.434

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures, including the primary therapy-satisfaction endpoint and one secondary outcome concerning marijuana use as measured by subjective report of daily smoking sessions. Multiple outcomes can raise a multiplicity issue when several statistical tests are conducted, because interpreting many tests without a prespecified strategy can increase the chance of finding an apparently notable result by chance. This is a general statistical concern, not evidence that such a problem occurred in this trial.

The registry record does not report a multiplicity strategy, a hierarchy of outcomes, or an adjustment for multiple testing. It also lists zero analyses, so there are no posted inferential tests from which to assess how multiplicity was handled. The available record does not include a numerical result for the listed secondary outcome.

For the primary endpoint, the arm summaries include 6 participants in the oxytocin group and 7 in the saline group. Overall enrollment is listed as 16. The record does not explain the relation between overall enrollment and the endpoint sample sizes. It does not report whether outcome data were missing, why endpoint counts differ, or whether participants were excluded from an analysis.

Missing-data methods can affect estimates when some outcomes are unavailable. Common approaches rely on assumptions about why data are missing; those assumptions and methods should be described rather than inferred from the final sample counts. Neither the missing-data approach nor the reasons for any unrepresented observations are reported in the registry record. The analysis population—such as whether participants were analyzed according to randomized assignment—is also not reported.

These omissions limit assessment of the endpoint summaries and any intended treatment comparison. They do not establish that missing data or multiplicity affected the results; they mean the registry record does not provide enough information to evaluate those issues.

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 0% reporting threshold.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for 8 participants at risk in each arm. The serious adverse event count is 0 in the oxytocin group and 0 in the saline group. These are counts within the listed at-risk groups; they do not establish that no adverse events of any kind occurred.

For other adverse events, the registry reports 1 affected participant among 8 at risk in the oxytocin group and 2 affected participants among 8 at risk in the saline group. These are descriptive counts. The record does not provide event terms for these other adverse events, so their nature and severity cannot be characterized from the information. The list of top serious adverse-event terms is empty.

Adverse-event counts should be read separately from the primary endpoint summaries. The safety groups each have 8 participants at risk, while the primary endpoint means are based on 6 and 7 participants. The registry does not explain the relationship between these sets of counts. A difference in observed counts does not by itself show that an intervention caused an event, and the record does not report a causal safety analysis.

Death information is not reported in the registry record. The absence of a listed death count should not be interpreted as a reported zero. The safety information is limited to the counts and group sizes stated above; further details about collection periods, event definitions, or attribution are not reported.

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

The posted primary endpoint results describe subjective satisfaction at the last MET session. The mean score is 9.8 in the oxytocin arm and 9.7 in the saline arm, with standard errors of 0.4 and 0.3, respectively. The scale ranges from 0, most dissatisfied, to 10, most satisfied. These summaries indicate that the reported average ratings were toward the satisfied end of the scale in both groups.

Those descriptive observations do not establish a treatment effect. The registry does not provide an estimable two-arm continuous comparison, a treatment-effect estimate, a confidence interval, or a p-value. Without a reported comparison, it is not possible to state how precisely the trial distinguishes the randomized arms on satisfaction. The reported arm means are not evidence by themselves that oxytocin changed satisfaction relative to saline.

The endpoint also has a specific scope. It measures a participant’s subjective account of the final MET session; it does not directly measure marijuana use, and it is not a comprehensive measure of therapy response. A high average satisfaction score cannot be used to conclude that marijuana consumption changed or that a treatment produced clinical benefit. The listed secondary outcome concerns subjective reports of daily smoking sessions, but no numerical result for that outcome is available in the registry record.

The overall enrollment is 16, whereas the endpoint summaries include 6 and 7 participants. The record does not explain this relationship, so the reasons for the endpoint counts cannot be determined. This limits interpretation of who is represented by the summaries. The record also does not report the analysis population, missing-data methods, or a protocol-based analysis plan.

Thus, the defensible interpretation is narrow: the registry contains arm-level descriptive satisfaction scores and limited adverse-event counts, but it does not contain an estimable primary comparison. The findings should not be extended to outcomes or populations that are not characterized by the reported information.

14. Why This Trial Matters Statistically

This trial illustrates the distinction between reporting outcome summaries and reporting a comparative treatment effect. A randomized design makes a between-arm comparison central to the study question, but the availability of a mean for each arm does not itself answer that question. The registry lists the primary endpoint means and standard errors, yet marks the continuous comparison as missing or not estimable and lists no analyses.

That distinction matters for biostatistical interpretation. Descriptive values tell readers what was recorded in the endpoint groups. Inferential results would additionally quantify the contrast and its uncertainty under a stated analysis. Without the latter, readers cannot judge how compatible the observed summaries are with a range of possible treatment effects. Reporting the limitation directly is more informative than treating the means as a completed comparison.

The endpoint also demonstrates why outcome meaning matters. Session satisfaction is a subjective measure of the therapy experience, based on four SRS items. It is distinct from marijuana use, even though marijuana use appears as a secondary outcome. The registry’s stated study purpose mentions both use and therapy response, but the available numerical endpoint information concerns satisfaction alone. Keeping those concepts separate prevents an outcome from being interpreted beyond what it measures.

Finally, the record shows why sample counts and analysis details are part of results interpretation. Overall enrollment is 16, while the primary endpoint summaries use smaller arm counts; the reasons are not reported. The record also does not specify missing-data methods or analysis populations. These are not merely technical details: they determine how readers understand which observations contribute to a result and what population the result describes. The trial is therefore a useful example of how a completed registry record can contain outcome summaries while leaving key inferential and analytic questions unresolved.

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 primary limitation for interpretation is that the registry does not report an estimable two-arm comparison for the continuous endpoint. The arm means and standard errors are available, but a treatment-effect estimate, confidence interval, and p-value are not. The reasons the comparison is marked missing or not estimable are not reported in the registry record.

The endpoint sample sizes are 6 and 7, while overall enrollment is 16. No explanation is reported for the difference or for which participants contributed to the endpoint summaries. The registry does not describe missing observations, exclusions, or analysis populations. As a result, the representativeness of the endpoint summaries cannot be assessed from this record.

Other design and analysis details are also not reported: random-sequence generation, allocation concealment, which parties were masked, intervention dose and schedule, sample-size justification, analysis methods, model assumptions, and any planned handling of multiple outcomes. These details should not be inferred from the labels randomized, double-masked, or completed.

The primary endpoint is a subjective satisfaction score at the last MET session. The record does not report individual scores or a numerical result for the listed secondary outcome concerning daily smoking sessions. Consequently, the information available does not characterize the distribution of satisfaction scores or establish results for marijuana use. The endpoint’s specific measurement timing also limits it to the stated final-session assessment.

Safety reporting is limited to serious-event counts and other-event counts, with no event terms for the latter. Death information and further safety details are not reported in the registry record. These limitations concern what can be concluded from the record; they do not establish that unreported procedures or outcomes were absent from the underlying study.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Effect of Oxytocin on Craving and Therapy Response — NCT01827332.
• Registry record last updated 2017-01-02; status last verified 2016-11.
• Results first posted 2016-11-11.
• 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 a completed, randomized, double-masked, parallel-group study of intranasal oxytocin and intranasal saline in marijuana-dependent individuals. Overall enrollment is 16. The primary endpoint is subjective satisfaction measured by the Session Rating Scale at the last Motivational Enhancement Therapy session.

The reported mean is 9.8 with standard error 0.4 among 6 participants in the oxytocin arm, and 9.7 with standard error 0.3 among 7 participants in the saline arm. The two-arm continuous comparison is marked missing or not estimable, and no analyses are listed. One secondary outcome concerning subjective reports of daily smoking sessions is listed, but no numerical result is available in the record used for this analysis.

Serious adverse events are reported for 0 of 8 participants at risk in each arm. Other adverse events are reported for 1 of 8 in the oxytocin arm and 2 of 8 in the saline arm. The reasons for the endpoint sample counts, analysis methods, missing-data handling, and death information are not reported in the registry record.