Rhodiola Rosea Therapy of Major Depressive Disorder: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Rhodiola Rosea Therapy of Major Depressive Disorder (NCT01098318), a randomized phase 3 study. The primary outcome is Depressive Symptoms as Measured by the Hamilton Depression Rating Scale (17-items) at Week 8 and Week 12..

2. Clinical Question

3. Trial Design

The registry identifies this as a phase 3, randomized, triple-masked, parallel-group trial. It records an enrollment of 58 and lists Rhodiola rosea, sertraline, and a sugar pill as the study arms. Triple masking is the registry’s description; which people involved in the trial were masked, and how masking was implemented, are not reported in the registry record. The allocation method beyond being randomized is also not reported.

The study began in 2010-06, had a primary completion date of 2013-07, and is marked completed. Those dates describe the registry record and do not provide details about recruitment duration, the timing of individual participants’ assessments, or any changes to the planned study.

The registry’s brief summary frames the study as an examination of Rhodiola rosea compared with a conventional antidepressant drug. The listed sertraline and sugar-pill arms mean that the study record includes more than that pair of treatments. The record does not specify which comparisons were prespecified as primary, whether all arms were included in each analysis, or how the sugar-pill arm was used in the analysis.

Other design details needed to assess the trial fully—including eligibility criteria, treatment duration by participant, adherence procedures, and the planned statistical analysis—are not reported in the registry record. Randomization and masking can help reduce certain sources of bias, but those design labels alone do not establish how successfully these safeguards were carried out.

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.

6. Primary Endpoint

The registry lists the primary outcome as Depressive Symptoms as Measured by the Hamilton Depression Rating Scale (17-items) at Week 8 and Week 12., measured over 12 weeks.

The primary endpoint is depressive symptom severity measured using the 17-item Hamilton Depression Rating Scale, or HAM-D17. The registry describes the measure as a validated, clinician-rated instrument for assessing the severity of major depressive disorder symptoms. It states that the 28-item Hamilton scale was used to determine the primary outcome score from its 17-item form. The score ranges from 0 to 68, with higher scores indicating more depressive symptoms.

The record names Week 8 and Week 12 as assessment time points and gives a 12 weeks timeframe. It does not explain how scores from those time points were intended to be combined or which time point was the principal basis for a treatment comparison. The record also does not provide the observed scores, changes from baseline, or between-arm estimates.

Using a standardized symptom scale can make symptom severity assessable in a consistent format, while clinician rating provides a structured assessment rather than relying solely on an unstructured description. A scale score is still a measure of symptoms, not a complete account of a person’s experience or broader functioning. The registry record does not report the assessment procedures, rater training, or details of how missing assessments were handled.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The trial is recorded as randomized and parallel-group. In a randomized study, treatment assignment is intended to make groups comparable, on average, with respect to both measured and unmeasured characteristics. Randomization does not guarantee that groups will be identical, especially in a study with limited enrollment. The registry record does not report the sequence-generation method, allocation concealment, or details about implementation, so those aspects cannot be evaluated.

Parallel-group design means participants are assigned to a study arm and assessed over the trial rather than being described as crossing through each treatment. The registry lists Rhodiola rosea, sertraline, and a sugar pill. It does not report the planned contrasts among those arms or whether the primary analysis was intended to compare every arm or particular pairs of arms. That distinction matters because a treatment contrast is the specific difference an analysis estimates.

The record calls the study triple-masked. Masking is intended to reduce the influence of treatment knowledge on behavior, assessment, or reporting. The registry does not identify the roles covered by the masking label or describe its procedures. The label therefore records the stated design, but does not by itself establish whether masking was maintained.

What does a mean and standard deviation describe?

The primary outcome is continuous: it is a score on the HAM-D17 scale. A mean gives the average score for a group at a specified assessment. A standard deviation describes how dispersed individual scores are around that mean. These summaries answer different questions: the mean describes the group average, while the standard deviation describes variability among observations. Neither summary alone provides a direct estimate of the uncertainty in a difference between groups.

A comparison of mean scores can be expressed as a contrast between groups. To interpret such a contrast, readers need to know the estimate, its uncertainty, the time point, and the analysis population. The registry record does not report the primary endpoint means, standard deviations, or a contrast. It therefore does not support a recalculation of the primary treatment effect from posted summary statistics.

What does a confidence interval contribute?

In general, a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the analysis. For a treatment contrast, it can show which values are compatible with the data and the statistical method. A narrow interval indicates greater precision than a wide interval, but the interpretation also depends on what sizes of difference would matter in context. No confidence interval for the primary endpoint is reported in the registry record.

A p-value, when reported, describes how incompatible the observed data are with a specified statistical null model, given the assumptions used. It is not the probability that a treatment works, and it does not measure the size or importance of an effect. The registry record does not report a primary-outcome p-value or a statistical testing procedure. No conclusion about statistical significance can therefore be drawn from the primary endpoint record.

Why do multiple time points matter?

The primary outcome description names Week 8 and Week 12. When an outcome is assessed at more than one time point, an analysis needs to define how the assessments relate to the main question. It might designate a principal time point, model change over time, or address each time point separately; these are general analytical possibilities, not methods reported for this trial. Different choices can lead to different estimates and different uncertainty. The registry record does not report the intended approach, and the primary endpoint is not presented as a single comparison.

Repeated assessments from the same participant are related rather than independent. General methods for repeated measurements account for that within-person relationship and can use information across assessments, subject to assumptions about the model and missing observations. The registry record does not identify whether repeated-measures methods were planned or used.

How should planning calculations be read?

Any sample-size figures associated with planning are illustrations, not observed power. The stated illustration uses the observed effect as its basis, assumes a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. These assumptions describe the illustration, not the original trial design. Such calculations do not show the probability that the completed trial found a true effect, and they do not replace an estimate with its confidence interval. The registry record does not report the original sample-size justification or the trial’s own power calculation.

Statistical precision depends on the variability of the endpoint and the amount of usable data, as well as the analysis method. Planning figures based on an observed effect are particularly dependent on that effect estimate and should not be treated as a guarantee of precision in a future study. Since the primary estimate is not reported in the registry record, no numerical planning value can be interpreted as a direct account of the primary outcome results.

10. Multiplicity, Missing Data and Analysis Populations

The record identifies a primary symptom outcome at Week 8 and Week 12, and lists secondary outcomes addressing clinical global impressions, depressive symptoms on the Beck Depression Inventory, sexual function, suicide ideation, and treatment-emergent side effects. It also lists 6 outcome measures and 0 analyses. The registry record does not report a statistical plan describing which outcomes or time points were primary for testing, how multiple comparisons were handled, or whether any outcome hierarchy was used.

In general, examining multiple outcomes, time points, or treatment contrasts creates multiple opportunities to observe a result that appears notable by chance. Methods for addressing multiplicity can include prespecifying a primary comparison, adjusting inference, or treating additional analyses as exploratory. These are general options; the registry record does not say which, if any, were used in this trial.

Missing-data methods are also not reported in the registry record. The available record does not state how many participants had endpoint observations, why observations may have been missing, whether participants were analyzed according to randomized assignment, or how missing scores were handled. These details matter because analyses based on different participant subsets or assumptions about missingness can yield different estimates.

The registry record does not report the analysis population, protocol deviations, or the statistical model for the primary endpoint. Accordingly, the posted information is not sufficient to assess whether the analysis followed an intention-to-treat approach, how repeated assessments were modeled, or how robust conclusions would be to alternative missing-data assumptions.

11. 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 safety record separates serious adverse events from other adverse events. For serious adverse events, it records 0 participants affected among 20 at risk in the Rhodiola Rosea arm, 0 among 19 at risk in the Sertraline arm, and 0 among 18 at risk in the Sugar Pill arm. These are the serious-event counts recorded in the registry; they do not provide details about event definitions, collection procedures, or follow-up completeness.

For other adverse events, the record lists 6 participants affected in the Rhodiola Rosea arm, 12 in the Sertraline arm, and 3 in the Sugar Pill arm. These figures are categorized as other adverse events and should not be read as serious adverse event counts. The registry does not give event-level descriptions in the information recorded here, or explain whether participants could have experienced more than one event.

Death entries are not reported in the registry record. A missing death entry is not the same as a recorded zero. The serious-event terms list is empty, which does not add information about the circumstances or ascertainment of events. These safety counts alone do not establish comparative risk or explain whether an event was caused by treatment.

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

The registry record establishes that a randomized, triple-masked, parallel phase 3 trial was conducted and marked completed, with an enrollment of 58. It identifies the study arms and the intended primary measure of depressive symptoms. It also records safety counts for serious and other adverse events. These registry entries describe the study and its posted registry information; they are not a substitute for comparative outcome estimates.

The primary outcome information does not include group scores or an estimated difference at Week 8 or Week 12. Without an estimate and its uncertainty, the record cannot show whether the arms differed, how large any difference may have been, or whether the available data are compatible with a broad range of effects. It also cannot establish that there was no difference. Absence of a numerical primary result is an evidence gap, not a result favoring any arm.

The record’s descriptions of Rhodiola rosea, sertraline, and a sugar pill identify the treatments studied, but they do not establish a treatment effect. The brief summary states the study’s purpose; a stated objective is not an outcome finding. Likewise, the completion status does not show that the planned analyses were conducted or that their results were entered in the registry.

The adverse-event counts provide limited descriptive information. They do not include the detail needed to assess event severity beyond the serious-versus-other categorization, timing, duration, or attribution. The unreported death entries should not be interpreted as zero deaths. Safety counts also cannot answer the primary question about symptom scores.

Overall, the posted record supports a description of the design, endpoint, and selected safety counts, but it does not support a conclusion about comparative symptom outcomes. Judging the evidence would require outcome estimates, uncertainty intervals, analysis details, and information about missing data that are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial matters statistically because it places an herbal extract, a conventional antidepressant, and a sugar pill within a randomized, triple-masked, parallel design. Those design features describe an attempt to make comparisons in a controlled framework. They do not, by themselves, tell readers what the comparisons found or how precisely the effects were estimated.

The primary outcome is a clinician-rated continuous symptom score, and it is named at Week 8 and Week 12. That makes the definition of the treatment contrast and handling of repeated assessments important to interpretation. The registry record does not specify a single primary comparison or report a numerical endpoint result. The gap illustrates why an endpoint description alone cannot answer a comparative-effectiveness question.

The record also demonstrates the distinction between an outcome measure and a reported analysis. It lists outcome measures but no analyses, and the primary outcome has more than one time point without a single comparison being reported. Readers cannot infer that a particular statistical model, multiplicity adjustment, or missing-data procedure was used.

Finally, the safety information illustrates why event categories and denominators must be kept distinct. Serious events are listed separately from other events, and death entries are not reported. These details may be read descriptively, but they do not replace a full account of ascertainment or support causal conclusions. Statistical interpretation depends not only on design labels and counts, but also on complete outcome estimates and transparent analytical reporting.

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 of the registry record is the absence of a numerical primary-outcome comparison. Although the endpoint and assessment times are named, the record does not give HAM-D17 scores, changes, treatment contrasts, confidence intervals, or p-values. The primary endpoint is not reduced to a single comparison, limiting interpretation of the main research question.

Important design and analysis details are not reported in the registry record. These include eligibility criteria, allocation procedures, masking implementation, treatment administration details, the prespecified statistical plan, analysis populations, and handling of missing data. Without these details, readers cannot fully evaluate the conduct of the trial or the assumptions behind an analysis.

The record lists secondary outcomes but does not provide their results or explain how multiple outcomes and time points were addressed. The entry of 0 analyses does not establish that no analyses occurred; it means that analyses are not reported in the registry information. It also prevents comparison of reported findings with a specified analysis plan.

The safety record gives arm-specific counts, but does not report event descriptions, timing, duration, collection procedures, or treatment attribution. Death entries are not reported, which must not be interpreted as no deaths. The counts therefore offer only limited descriptive information.

Finally, enrollment and completion status do not establish how many participants contributed usable data to each endpoint or whether all randomized participants were followed. These limitations constrain interpretation of efficacy and safety, and they preclude conclusions about treatment differences from the registry record alone.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Rhodiola Rosea Therapy of Major Depressive Disorder — NCT01098318.
• Registry record last updated 2018-02-22; status last verified 2018-01.
• Results first posted 2016-05-18.
• 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.

18. Record Summary

The registry record describes NCT01098318, titled “Rhodiola Rosea Therapy of Major Depressive Disorder.” It is marked phase 3, randomized, triple-masked, parallel, and completed. Enrollment is recorded as 58, with a start date of 2010-06 and a primary completion date of 2013-07.

The listed arms are Rhodiola rosea herbal extract, sertraline, and a sugar pill identified as lactose monohydrate. The primary outcome is HAM-D17 depressive symptom severity at Week 8 and Week 12, with a 12 weeks timeframe. The record describes a score range of 0 to 68 and says that higher scores indicate more depressive symptoms.

The registry lists secondary outcomes and safety counts, but does not report a numerical primary-outcome comparison, analysis details, or death entries. The primary outcome is not presented as a single comparison. Consequently, the posted record describes the trial question and selected study information without establishing a comparative symptom result.