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 Minocycline for Treatment of Posttraumatic Stress Disorder in Veterans (NCT03340350), a na phase 4 study. The primary outcome is PTSD Symptom Severity.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03340350 |
| Phase | Phase 4 |
| Condition | PTSD |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 10 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Sriram Ramaswamy |
| Results posted | Yes |
2. Clinical Question
Population
Veterans with PTSD were the population of interest. The registry record reports an enrollment of 10, but does not report further eligibility details or a description of the enrolled participants in the primary outcome record.
Intervention
The study evaluated adjunctive minocycline. The recorded regimen was 100 mg/day from day 1 to day 7, then 200 mg/day from day 8 through the end of week 12. The registry summary frames the study as evaluating safety and efficacy.
Comparator
No separate comparator is recorded. This was a single-group study, with allocation listed as NA and no masking. Therefore, the record does not describe a randomized or concurrent control-group comparison.
Primary question
The primary outcome was PTSD symptom severity, measured with total scores on the Past Month version of the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) at baseline and Week 12. The registry record does not report the scores, their change, or an analysis of that change, so it does not establish how symptom severity differed over the study period.
3. Trial Design
This was a completed Phase 4, single-group study with an enrollment of 10. The registry lists allocation as NA and masking as none. There was no separate control arm recorded, so the design is not a like-for-like comparison of minocycline with another treatment or with no added treatment.
The study evaluated adjunctive minocycline in veterans with PTSD. The recorded schedule was 100 mg/day from day 1 to day 7 and 200 mg/day from day 8 through the end of week 12. The listed primary outcome was PTSD symptom severity at baseline and Week 12. Secondary outcomes included depression symptom severity; clinical status for severity and improvement; and executive functioning measured through set shifting and verbal fluency.
The registry gives a study start date of 2017-05-10 and a primary completion date of 2018-06-01, and lists the overall status as completed. These dates describe the record’s study timeline; they do not supply outcome measurements or show when individual participants were assessed.
A single-group design can describe measurements made in participants over time, but it cannot by itself separate a treatment-associated change from other explanations, such as changes that would have occurred over time or effects of concurrent care. The registry record does not report additional design details that would clarify those issues. It also does not report a sample-size justification, an interim-analysis plan, or further details about the 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.
Overall Study
| Stage | Minocycline |
|---|---|
| STARTED | 10 |
| COMPLETED | 4 |
| NOT COMPLETED | 6 |
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 | Minocycline |
|---|---|---|
| Participants analysed | 10 | |
| Age, Continuous | years | 39.9 (SD 11.2) |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 9 |
| Race/Ethnicity, Customized: White | Participants | 6 |
| Race/Ethnicity, Customized: Black | Participants | 1 |
| Race/Ethnicity, Customized: Hispanic or Latino | Participants | 2 |
| Race/Ethnicity, Customized: Other | Participants | 1 |
| Region of Enrollment: United States | participants | 10 |
6. Primary Endpoint
The registry lists the primary outcome as PTSD Symptom Severity, measured over Baseline and Week 12.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | score on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was PTSD symptom severity assessed at baseline and Week 12. The measure was the total score on the Past Month version of the Clinician-Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (CAPS-5). The registry describes a score range from 0 to 80, with higher scores indicating greater severity of PTSD symptoms.
A symptom scale can turn participants’ reported or assessed symptoms into a numeric outcome that can be summarized across a group. The registry specifies the mean and standard deviation as the summary measures for this continuous endpoint. A mean describes the group’s average score, while a standard deviation describes how spread out scores are around that average. Comparing measurements at baseline and Week 12 can describe change over time, if the observations and analysis are reported.
The registry record does not report the baseline or Week 12 means, standard deviations, participant counts contributing measurements, or a change estimate. It also does not report a threshold for interpreting a change as clinically important. The outcome definition alone therefore identifies what was to be measured, but does not show the observed symptom pattern or its precision.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The available record characterizes a small, single-group study of adjunctive minocycline in veterans with PTSD. Its primary outcome was CAPS-5 symptom severity measured at baseline and Week 12. Although the record gives the scale’s range and direction, it does not report the observed scores at either assessment or an estimate of change. It also does not report a confidence interval, p-value, or other inferential result for the primary outcome. Consequently, the posted record does not establish the size or precision of any change in PTSD symptom severity.
The enrollment was 10, but this is not the same as the number with complete baseline and Week 12 outcome data. The registry record does not report the number contributing to either assessment or to an analysis of change. It is therefore not possible to determine from this record whether all enrolled participants had outcome data, or how any incomplete observations were handled.
The absence of a separate comparator is central to interpretation. A baseline-to-Week 12 difference, if reported, would describe change within the studied group. Without a concurrent comparison group, that pattern would not isolate the effect of minocycline from other influences. This is a general limitation of uncontrolled before-and-after comparisons, not a finding about what happened to participants in this study.
The registry lists 9 outcome measures and 0 analyses. Five named secondary outcome areas are depression symptom severity, clinical status for severity and improvement, and executive functioning through set shifting and verbal fluency. The record does not provide numerical results for these measures either. Nor does it report which observations were included in an analysis population or how missing data were treated.
The safety record lists 0 participants affected by serious adverse events, 4 affected by other adverse events, and 0 deaths among the 10 recorded as at risk in each category. These are the posted counts, not a comparison between treatment groups. The record does not list serious adverse event terms. The other adverse event count should not be conflated with the serious adverse event count.
Overall, the registry record supplies design and outcome definitions, along with adverse event counts, but lacks the outcome estimates needed to assess the primary endpoint. The study’s completed status does not substitute for reporting results. Any conclusion about the magnitude, uncertainty, or cause of symptom change would go beyond the statistical results recorded.
9. Statistical Methods Explained
The registry describes a continuous primary outcome summarized as a mean with a standard deviation. These summaries answer different questions. The mean locates the center of the observed scores, while the standard deviation describes their variability among participants. Neither is reported numerically for the CAPS-5 assessments in the registry record.
What a baseline-to-follow-up comparison would describe
In a general longitudinal analysis, repeated measurements can be compared by examining each participant’s later score in relation to that participant’s baseline score. A group summary of those within-person changes can describe whether scores tended to rise or fall over time. This is a general explanation of a possible approach, not a statement that the registry used it. The record does not report a change estimate, the analysis method, or the number of participants with paired observations.
A comparison of group means at two visits is not necessarily the same as an analysis of individual changes. Their estimates and uncertainty can differ because the measurements from the same participant are related. The statistical plan for this study, including how the repeated measurements were handled, is not reported in the registry record. It would therefore be inappropriate to assign a specific longitudinal method to this analysis.
Precision and statistical uncertainty
In general, a confidence interval gives a range of values compatible with the data and the method used, under its assumptions. A narrow interval indicates greater precision than a wide interval; an interval that includes values representing no change may indicate that the data do not distinguish that possibility from other effects at the interval’s confidence level. This general interpretation depends on the actual estimate and interval. Neither is reported for the primary outcome.
A p-value, when reported, describes how unusual data at least as inconsistent with a specified null hypothesis would be under the model assumptions. It does not measure the size or clinical importance of an effect. The registry record reports no primary-outcome p-value or analysis. No significance test, model, or adjustment can be inferred from the endpoint description alone.
Planning calculations are not study results
The planning illustration uses a two-sided significance level of 0.05, equal allocation between two hypothetical arms, and a normal approximation. It is described as using a stated fraction of an observed effect, and as a planning illustration rather than the trial’s own design. For continuous outcomes, the reported planning quantities are participants per arm for the specified power. Those assumptions do not describe the actual single-group design, which had an enrollment of 10 and no separate comparator recorded.
A planning illustration asks how many participants might be needed for a hypothetical comparison under stated assumptions. It is not an observed result and is not observed power. The registry record does not report the observed primary effect or the resulting planning counts in the registry record for this analysis. Without those values, no planning quantity can be interpreted as evidence about the study’s achieved precision.
In general, planning based on an observed effect can be sensitive to the estimate used: an imprecise or unusually large observed effect can make a planning target unstable. Any such illustration should be read as conditional on its assumptions, not as a formal justification for the enrolled sample. The registry record does not report its original sample-size justification, so the planning illustration should not be mistaken for that justification.
Why dispersion and model assumptions matter
For a continuous endpoint, the standard deviation matters because greater participant-to-participant variability makes a group mean less precise when other features are held constant. A normal approximation is a modeling assumption used in some calculations; its suitability depends on the data and design. The registry record does not report the observed score distribution, diagnostics, or a model assessment. No claim about whether the approximation fits the study data can be made.
Over-dispersion is a general concern for count outcomes when the observed variability exceeds what a chosen count model expects. It can make standard errors too small if ignored. That concept does not directly describe the CAPS-5 continuous endpoint, and no count-model analysis is reported for this trial. It is relevant only as a general reminder that methods should match the outcome’s distribution.
Finally, the record’s listing of 0 analyses means that no statistical analyses are listed in the registry record, not that a particular analysis found no effect. Without the numerical endpoint results, analysis population, missing-data handling, and inferential estimates, the primary outcome cannot be evaluated statistically from the posted record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 9 outcome measures, including the primary PTSD symptom severity endpoint and secondary measures of depression symptom severity, clinical status, and executive functioning. It lists 0 analyses. A multiplicity adjustment or testing hierarchy is not reported in the registry record.
In general, testing multiple outcomes can increase the chance of at least one apparently notable result arising by chance. Statistical plans may address this through a prespecified primary endpoint, an ordering of tests, or an adjustment to inference. These are general methods; the record does not say that any of them was used in this study. Because no outcome analyses are listed, there are no reported tests to evaluate for multiplicity.
The registry record does not report the number of participants with CAPS-5 results at baseline or Week 12, nor does it describe an analysis population. The enrollment of 10 should not be read as proof that 10 participants contributed to every endpoint or visit. Whether any measurements were missing, and how missing data were handled, is not reported in the registry record.
In general, missing outcome data can affect both the estimate and its uncertainty, especially if the likelihood of a missing measurement is related to a participant’s outcome. Common approaches rely on assumptions about why data are missing; those assumptions and methods should be described to support interpretation. No such method or assumption is recorded for this study. Therefore, the completeness and analysis of the repeated outcome measurements remain unclear.
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 |
|---|---|---|---|
| Minocycline | 0 | 10 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Minocycline | 0 of 10 |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Minocycline | 4 of 10 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Minocycline |
|---|---|---|
| Rash/hives | Skin and subcutaneous tissue disorders | 2 of 10 |
| Hospitalization | General disorders | 1 of 10 |
| Shortness of breath | Respiratory, thoracic and mediastinal disorders | 1 of 10 |
The registry lists 10 participants at risk for serious adverse events and 0 affected by a serious adverse event. It lists 10 at risk for other adverse events and 4 affected. The death count is 0. These are counts in the Minocycline group; the single-group design has no separate control-group safety count for comparison.
Serious adverse events and other adverse events are reported as distinct categories in the registry. The 4 participants affected by other adverse events should not be interpreted as having had serious adverse events. The record does not list serious adverse event terms, and it does not provide further detail about the other adverse events in the registry record for this analysis.
These counts describe what the registry records, not the likelihood of an event in another population or under another treatment. They also do not show how long each participant was observed for safety beyond the treatment period described in the record. The study’s enrollment was 10, but the event counts alone do not provide a controlled comparison or establish causation.
12. What the Result Does, and Does Not, Mean
The record documents a completed Phase 4, single-group study of adjunctive minocycline in veterans with PTSD. It specifies the treatment schedule and identifies CAPS-5 symptom severity at baseline and Week 12 as the primary outcome. It also records adverse event counts. These details explain what the study was intended to examine and what safety counts were posted.
The record does not report the primary outcome measurements or an analysis of them. It therefore does not show whether the average CAPS-5 score changed, how variable the scores were, or how precisely any change was estimated. It also does not report results for the listed secondary outcome measures. The absence of reported analyses is not evidence that an analysis found no effect, and completion status is not a substitute for numerical results.
Even if a within-group change were reported, a single-group design would describe change over time rather than provide a randomized comparison. General influences such as concurrent care, natural fluctuation, or changes in how symptoms are assessed can also affect before-and-after observations. The registry does not report enough information to determine how such influences were addressed.
The posted safety counts are limited to the recorded serious and other adverse event categories and deaths. Without a control group, those counts cannot show how event occurrence compares with another treatment condition. They also do not establish that an event was caused by minocycline.
Accordingly, the statistical record supports a description of the design, the specified measures, and the reported safety counts. It does not support a numerical conclusion about the primary symptom outcome or a causal conclusion about treatment efficacy or safety.
13. Why This Trial Matters Statistically
This study illustrates why the design and the result must be read together. The registry identifies a single-group study with an enrollment of 10, a defined minocycline schedule, and repeated assessment of PTSD symptom severity. Those details make clear what was intended to be measured, but they do not supply the actual outcome data.
For clinical research, a named endpoint is only the starting point for statistical interpretation. To understand the evidence, readers need the observed measurements, the participants contributing to them, an estimate of change, and an indication of its uncertainty. The registry record does not report those elements for the primary endpoint. Without them, neither the magnitude nor the precision of change can be assessed.
The lack of a concurrent comparator also matters. A change over time in one group can be informative descriptively, but it cannot on its own isolate the influence of the intervention. This distinction helps prevent a within-group pattern, if one is reported elsewhere, from being interpreted as a controlled treatment effect.
The safety counts offer a separate type of information: the record lists no serious adverse events, 4 participants affected by other adverse events, and no deaths. Their interpretation remains bounded by the small enrolled group, the absence of a comparison group, and the limited event detail recorded. The record also does not list analyses of the primary or secondary outcomes.
Statistically, the key lesson is that completion, outcome definitions, and event counts do not replace reported estimates and methods. A transparent account of analysis populations, missing observations, uncertainty, and the role of multiple outcomes is needed to judge how strongly results support a conclusion. Those details are not reported in the registry record.
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 principal limitation for interpreting this trial statistically is that the registry record does not report numerical results for the primary CAPS-5 outcome. Baseline and Week 12 means, standard deviations, changes, confidence intervals, and p-values are not reported in the registry record. Thus, the endpoint’s observed direction, size, and precision cannot be described.
The single-group design has no recorded concurrent comparator. Any within-group change would not, by itself, identify a treatment effect. The record also gives an enrollment of 10 but does not report how many participants contributed primary outcome data at each assessment. The completeness of follow-up and the handling of missing observations are not reported in the registry record.
The record lists 9 outcome measures and 0 analyses, without a reported multiplicity approach or a clear analysis population. No model, inferential procedure, or interim-analysis plan is described. A sample-size justification is also not reported in the registry record; planning illustrations based on an observed effect should not be treated as the trial’s original design rationale.
Safety interpretation is constrained by the lack of a comparison group and by limited event detail. The record reports counts for serious and other adverse events and deaths, but no serious event terms. It does not provide additional context about event timing or attribution in the registry record for this analysis.
These limitations concern what the registry record reports. They do not establish that the underlying study lacked analyses or that no additional information exists elsewhere.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Minocycline for Treatment of Posttraumatic Stress Disorder in Veterans — NCT03340350.
- Registry record last updated 2020-07-09; status last verified 2020-06.
- Results first posted 2020-06-17.
- 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
The registry record identifies NCT03340350, a completed Phase 4, single-group study of adjunctive minocycline in veterans with PTSD. Enrollment was 10. The recorded schedule was 100 mg/day from day 1 to day 7 and 200 mg/day from day 8 through the end of week 12.
The primary outcome was CAPS-5 PTSD symptom severity at baseline and Week 12, summarized as a mean and standard deviation. The record lists 9 outcome measures and 0 analyses. Numerical results for the primary and secondary outcomes are not reported in the registry record.
For safety, the record lists 0 participants affected by serious adverse events, 4 affected by other adverse events, and 0 deaths, with 10 at risk in each listed event category. The study has no recorded comparator, so the safety counts are not comparative estimates.