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 Behavior During Experimentally Induced Pain (NCT01594528), a non-randomized na study. The primary outcome is Indicators / Minute.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01594528 |
| Phase | NA |
| Condition | Schizophrenia, Major Depression |
| Allocation | Non-Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 49 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Centre Hospitalier Esquirol |
| Results posted | Yes |
2. Clinical Question
Population
Participants with schizophrenia, participants with major depression, and controls without psychiatric trouble took part in experimental pain tests. The registry reports total enrollment of 49, but group-specific enrollment is not reported in the registry record.
Intervention
The recorded intervention is “pain tests,” classified as other. The registry describes observation during experimentally induced pain; the specific procedures used to induce pain are not reported in the registry record.
Comparator
The groups were defined by diagnosis, with controls described as people without psychiatric trouble. Allocation was non-randomized, and the registry cautions that the arms are not a like-for-like control comparison. How participants entered each group is not reported in the registry record.
Primary question
The pilot study aimed to examine infra-verbal behavioral signs during experimentally induced pain. Its primary outcome was the median number of corporal mobility, facial expression, and sound indicators per minute during pain tests. Numerical group results are not reported in the registry record.
The underlying question concerns observable behavior during pain, rather than a direct measure of pain intensity or a report of pain experience. The study description frames pain processing as involving emotional, sensory, and cognitive components, and proposes that individual differences in emotional and cognitive characteristics may be related to behavior. It also notes that psychiatric conditions may involve changes in these components, while their relationship to behavior during pain had not been studied in the way described by the investigators.
This is a descriptive, exploratory question across diagnostic groups, not a randomized treatment question. The registry does not report a prespecified contrast, a directional hypothesis, or the expected size of a group difference. It also does not report whether the main aim was to distinguish each psychiatric group from controls, compare the two psychiatric groups with one another, or describe patterns within each group. Without those details and the outcome estimates, the record does not establish what group differences were observed or how precisely they were estimated.
3. Trial Design
The registry identifies this as a completed pilot study with a non-randomized, parallel design and no masking. It lists enrollment of 49 and the conditions schizophrenia and major depression, alongside a control group described as having no psychiatric trouble. The sponsor is Centre Hospitalier Esquirol. The recorded start is 2012-04, and primary completion is 2013-12. The phase is listed as NA.
Non-randomized allocation means that assignment to the diagnostic groups was not described as a random process. The registry specifically cautions that the arms are not a like-for-like control comparison. Differences between groups could therefore reflect characteristics other than diagnosis, including factors associated with how participants were selected or their circumstances. Which characteristics were measured, balanced, or adjusted for is not reported in the registry record. The comparison should consequently be read as observational rather than as a randomized estimate of a causal effect.
In a parallel design, participants belong to separate groups rather than crossing between the listed conditions. The arm descriptions say that facial, corporal, and vocal indicators were observed during experimental pain tests for the schizophrenia, major depression, and control groups. They do not provide group-specific sample sizes or describe the process used to assign participants to the groups. Those details are not reported in the registry record.
The registry lists “pain tests” as the intervention, classified as other. It does not describe the test procedures, the pain stimulus, the order of assessments, the setting, or how long each participant was observed beyond giving the primary outcome timeframe as during pain tests, average 1 hour. Masking is listed as none; who knew the group assignments and whether outcome assessors were aware of them are not reported in the registry record.
The study is described as a pilot focused on infra-verbal behavior. The registry does not report a protocol, a sample-size justification, eligibility criteria, participant flow, or a detailed statistical analysis plan. Completion status and dates describe the administrative record, but do not supply the missing outcome estimates or explain how the analyses were conducted.
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 | Control | SChizophrenia | Major Depression |
|---|---|---|---|
| STARTED | 16 | 17 | 16 |
| COMPLETED | 16 | 17 | 16 |
| NOT COMPLETED | 0 | 0 | 0 |
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: subjects with major depression
| Characteristic | Unit | Major Depression | Schizophrenia | Control | Total |
|---|---|---|---|---|---|
| Participants analysed | 16 | 17 | 16 | 49 | |
| Age, Continuous | years | 46 (37.5 to 51.5) | 42 (35 to 49) | 40 (33.5 to 48.5) | 41 (35 to 50) |
| Sex: Female, Male: Female | Participants | 13 | 3 | 6 | 22 |
| Sex: Female, Male: Male | Participants | 3 | 14 | 10 | 27 |
| Region of Enrollment: France | Participants | 16 | 17 | 16 | 49 |
6. Primary Endpoint
The registry lists the primary outcome as Indicators / Minute, measured over during pain tests (average 1 hour).
| Element | Registry entry |
|---|---|
| Result type | Median |
| Measure of spread | 95% Confidence Interval |
| Unit | indicators/minute |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is titled “Indicators / Minute” and is expressed in indicators per minute. It counts corporal mobility, facial expression, and sound indicators during experimental pain tests. The listed timeframe is during pain tests, with an average duration of 1 hour. The registry specifies the median as the summary measure and a 95% confidence interval as its dispersion measure.
This endpoint is used to characterize observable behavior during the pain tests. A rate per minute relates the indicator count to observation time, while a median describes the middle of the observed values rather than their arithmetic average. These summaries can be useful when observations are unevenly distributed or some participants display many more indicators than others. The registry does not report how indicators were defined, counted, or combined, or whether the three types contributed equally to the endpoint.
As a behavioral measure, the endpoint is not itself a direct measure of subjective pain intensity, emotional state, or willingness to communicate. It records the listed outward signs. The registry does not report whether the endpoint was validated against another measure or whether observer agreement was assessed.
The median estimates and confidence intervals for the groups are not reported in the registry record. Without those values, readers cannot assess the observed level of behavioral indicators, the differences between groups, or the precision of the estimates.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a primary outcome but does not report numerical outcome results. In particular, it gives no median indicators-per-minute estimates, 95% confidence intervals, or numerical contrasts among the schizophrenia, major depression, and control groups. The direction, magnitude, and precision of any group differences therefore cannot be determined from the registry record.
The endpoint is a rate of observed corporal mobility, facial expression, and sound indicators during pain tests. A difference in that rate, if present, would describe a difference in recorded behavior under the study conditions. By itself, such a difference would not establish a difference in subjective pain, the underlying experience of pain, or the cause of a behavioral pattern. The registry does not report additional measures that would allow those interpretations to be evaluated.
The non-randomized design is especially important when interpreting group comparisons. Diagnostic groups may differ in ways beyond the diagnosis used to define them. The registry does not report the participant characteristics, group composition, adjustment variables, or analysis methods needed to judge whether such differences were addressed. As the registry itself cautions, the arms are not a like-for-like control comparison. Any numerical contrast should therefore be understood as an association across the observed groups, not as evidence that diagnosis caused a behavioral difference.
The median and confidence interval are appropriate concepts for describing a typical value and its uncertainty, but their interpretation depends on the data and analysis. A 95% confidence interval conveys uncertainty around an estimate under the assumptions of the method used; it does not show the full spread of individual observations, and it is not a guarantee that a particular interval contains the true value. The registry does not report the interval construction method, distribution of individual observations, or estimates themselves, so the practical precision cannot be judged.
The study is described as a pilot. Its stated aim is exploratory, and the registry does not report a prespecified hypothesis, a sample-size justification, or an analysis plan that would clarify which group comparisons were primary. The record lists one outcome measure and three analyses, but does not explain how those analyses relate to the outcome or to particular comparisons. That information is not reported in the registry record.
Planning illustrations associated with the study use the observed effect and specify a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; they are described as planning illustrations rather than the trial's design. They cannot substitute for missing outcome estimates or be interpreted as observed power. The effect used for those illustrations and their numerical results are not reported in the registry record. Overall, the available description supports understanding the study question and endpoint, but not judging what the study found.
9. Statistical Methods Explained
The registry identifies the primary summary as a median with a 95% confidence interval. It also lists three analyses, but does not explain what each analysis represents, which groups were contrasted, or which statistical procedures were used. The explanations below describe the statistical concepts in general; they are not claims about unreported methods used in this study.
What does a median describe?
In general, the median is the middle value after observations are ordered. It is less affected than the arithmetic mean by a small number of unusually high or low observations. For a behavioral indicator rate, that can be useful if participants' observed rates vary substantially. The median does not communicate the full distribution: participants can have very different values even when their group medians are similar. The registry does not report individual values, other distribution summaries, or plots of the observed data.
What does a confidence interval add?
In general, a confidence interval describes uncertainty in an estimate under the assumptions of the statistical method used. A narrower interval indicates greater precision under those assumptions; a wider interval indicates less precision. The 95% confidence interval specified for this endpoint is intended to accompany the median estimate. It does not mean that 95% of individual participants' observations fall within the interval, nor does it measure the range of individual behavior. The interval values and the method used to calculate them are not reported in the registry record, so their precision and assumptions cannot be checked.
Why does the design matter for comparisons?
In general, random allocation can help make groups comparable with respect to factors other than the assigned intervention. This study is listed as non-randomized and groups participants by diagnosis. Group differences may therefore reflect diagnosis, other participant characteristics, selection into groups, or a combination of factors. A statistical adjustment can address measured covariates under appropriate assumptions, but it cannot automatically remove bias from unmeasured factors. The registry does not report whether adjustments were made or which variables were included.
The parallel structure means the listed groups are distinct rather than repeated conditions for the same participants. The registry does not provide a detailed participant flow or group-specific sample sizes. Those omissions matter for assessing how much information contributed to each group estimate and whether the compared populations were assembled in comparable ways.
How should a rate outcome be considered?
In general, a count divided by observation time can be analyzed as a rate. The endpoint is expressed per minute, but the registry does not state whether the analysis used a rate model, a direct calculation for each participant, or another approach. It also does not report how observation times varied, whether all indicator types were combined before analysis, or how missing observations were handled.
In general, over-dispersion occurs when count data vary more than a statistical model expects. If a count model assumes less variability than the data contain, uncertainty can be understated and tests can be too optimistic. This is a general issue to consider for count outcomes, not a claim that over-dispersion occurred in this study. The registry does not identify a count model or report a dispersion assessment.
What can the planning illustrations tell readers?
The registry describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. These are planning assumptions, not evidence that the trial itself used that design or those assumptions. The illustrations are not observed power. In general, sample-size planning calculations depend on the effect size being targeted, variability, allocation, and the chosen statistical assumptions. The observed effect and the numerical planning results are not reported in the registry record, so their implications cannot be evaluated from this information.
The registry's general description distinguishes participants per arm for ordinary outcomes from total events for time-to-event outcomes. The primary endpoint is an indicators-per-minute outcome, not a time-to-event endpoint. The record does not provide numerical planning results for it in the registry record described, and no additional sample-size values can be inferred from the total enrollment alone.
What remains unknown about the analysis?
The registry does not report the statistical test or model, the confidence-interval construction, handling of ties or zero values, covariate adjustment, or whether any assumptions were checked. It also does not explain whether the three analyses correspond to the three diagnostic groups, pairwise comparisons, or something else. These details are needed to reproduce the analyses and judge whether the reported uncertainty matches the data structure. Because the numerical results are also absent, statistical significance and the size of any association cannot be assessed.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists one outcome measure and three analyses. It does not explain what the three analyses were, whether they were separate group comparisons, or which comparison was intended to be primary. A count of analyses alone does not establish that multiple hypotheses were tested, but it does make the missing analysis descriptions important for interpretation.
In general, multiplicity arises when several statistical questions are tested and the chance of a false-positive finding is not accounted for. Researchers may prespecify a primary comparison or use an adjustment strategy, but the registry does not report whether either approach was planned or used. The significance level listed for the planning illustrations does not establish the testing procedure used for the study's results.
Missing-data handling is not reported in the registry record. The record does not state whether all enrolled participants completed the pain tests, whether outcome observations were incomplete, or how any missing values were handled. It also does not identify an analysis population, such as participants analyzed according to a defined eligibility or completion rule. Without participant flow and analysis-population details, the number of people contributing to each endpoint estimate cannot be established.
These omissions do not show that data were missing or that analyses were improperly conducted. They mean the registry record does not let readers evaluate these aspects of the analysis. Numerical estimates, confidence intervals, prespecified comparisons, and population definitions would be needed for a fuller assessment.
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 |
|---|---|---|---|
| Diagnosis | 0 | 49 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Diagnosis | 0 of 49 |
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 |
|---|---|
| Diagnosis | 0 of 49 |
The adverse-event record lists a group titled “Diagnosis,” with 49 participants at risk for serious events and 0 affected. It also lists 49 at risk for other events and 0 affected, with 0 deaths. No top serious-event terms are listed. These are the counts recorded in the registry; they are not outcome estimates for the behavioral endpoint.
Zero affected participants in a registry entry means that no affected participants are recorded in that entry. It does not, by itself, establish that every participant was monitored completely or that no event occurred outside the recorded definitions or observation period. The record does not describe safety-monitoring procedures, the period of safety follow-up, event definitions, or the completeness of reporting.
The adverse-event entry is not broken down by schizophrenia, major depression, and control group. It therefore cannot be used to compare event counts across those groups. The number of participants at risk is reported as 49 for each event category, but the registry does not explain the group-level accounting or participant-level exposure. No interpretation about relative safety across groups can be drawn from these aggregate counts.
12. What the Result Does, and Does Not, Mean
The registry describes a pilot study asking whether behavioral indicators during experimentally induced pain can be characterized across people with schizophrenia, people with major depression, and controls. It defines an endpoint based on corporal mobility, facial expression, and sound indicators per minute, summarized by a median and a 95% confidence interval. These details clarify what the investigators intended to observe.
The numerical primary outcome results are not reported in the registry record. Consequently, the record does not establish the observed median in any group, whether the groups differed, the size of any difference, or the precision of any estimate. It also does not establish whether an observed pattern, if one was found, was consistent across indicator types or participants.
Even if group estimates were available, the endpoint would describe outward behavior during the recorded tests, not a direct measurement of pain experience. A behavioral indicator rate cannot on its own determine how much pain a participant felt or why a behavior occurred. The registry does not report validation measures or other information that would support a broader interpretation.
The non-randomized, parallel design also limits causal interpretation. The diagnostic groups are not described as being formed by random allocation, and the registry explicitly warns that the arms are not a like-for-like control comparison. Any group contrast would need to be interpreted in light of possible differences in participant characteristics and selection. The registry does not report enough detail to judge whether such differences were measured or accounted for.
The record therefore supports a description of the study's aim, population categories, design, and planned primary measure. It does not support a conclusion about the direction or magnitude of the findings, the certainty of a group difference, or a causal effect of diagnosis on behavior. Absence of numerical outcome results in the registry should not be mistaken for evidence of no difference.
13. Why This Trial Matters Statistically
This study addresses a measurement question: how to describe behavior that can be observed during experimentally induced pain when the main interest is not limited to verbal reports. The outcome combines corporal mobility, facial expression, and sound indicators into a rate per minute. That focus makes clear why defining the outcome and explaining how observations were collected are central to interpreting any result.
Statistically, the study also illustrates the distinction between describing groups and making causal comparisons. The registry identifies a non-randomized design and warns that the arms are not a like-for-like control comparison. This is a useful reminder that a numerical difference between diagnostic groups, even if reported, would not automatically isolate the effect of diagnosis from other group differences.
The selected summary is a median with a 95% confidence interval. In general, a median can give a robust account of a typical observation, while the confidence interval describes uncertainty in that estimate. Their usefulness depends on seeing the estimates, understanding the interval method, and knowing the distribution and analysis population. Those numerical results and methodological details are not reported in the registry record.
The record also shows why registration detail matters for exploratory studies. It identifies one primary outcome and three analyses, but does not describe the analyses or the intended comparisons. That gap makes it difficult to assess the relationship between the stated question and the reported statistical work. Clear specification of comparisons, missing-data handling, and group composition would help readers distinguish exploratory description from confirmatory testing.
The statistical importance of this study lies in the question and design rather than a result that can be evaluated from this record. Without outcome values, the record cannot quantify what was observed. It does, however, make visible the kinds of information needed to interpret behavioral measures in a non-randomized clinical comparison.
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 registry record contains important design and reporting limitations for interpreting this specific study. It reports total enrollment of 49 but not the number of participants in each diagnostic group. It does not provide eligibility criteria, recruitment methods, participant characteristics, or a participant flow. Group comparability and the amount of information supporting each group estimate therefore cannot be assessed.
The intervention is identified only as “pain tests.” The specific experimental procedures, stimulus characteristics, sequence, and observation conditions are not reported in the registry record. Although the primary endpoint timeframe is during pain tests, average 1 hour, the record does not explain the duration for individual participants or how observations were converted into indicators per minute.
The endpoint description names corporal mobility, facial expression, and sound indicators, but does not provide operational definitions, observer training, blinding of observers, or reliability assessment. Masking is listed as none; whether assessors knew the diagnostic group is not reported. These details matter when an outcome depends on recording and classifying behavior.
The record does not report primary outcome values, group-specific estimates, confidence intervals, or numerical comparisons. It also does not explain the three listed analyses, the analysis method, adjustment for participant characteristics, handling of missing data, or the analysis populations. The confidence-interval method and any treatment of variability are not reported.
Finally, the registry cautions that this is not a like-for-like control comparison. The non-randomized group structure limits causal conclusions, while the absence of results prevents even a descriptive assessment of group patterns. These are limits of what the registry record reports; they do not establish whether additional information exists outside the record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Behavior During Experimentally Induced Pain — NCT01594528.
- Registry record last updated 2019-03-22; status last verified 2018-12.
- Results first posted 2019-03-22.
- 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
NCT01594528, “Behavior During Experimentally Induced Pain,” is listed as a completed pilot study sponsored by Centre Hospitalier Esquirol. The registry records a non-randomized, unmasked, parallel design and total enrollment of 49. The recorded start is 2012-04, and primary completion is 2013-12. The phase is listed as NA.
The study aimed to examine infra-verbal behavior during experimentally induced pain among people with schizophrenia, people with major depression, and controls. The primary measure is the median number of corporal mobility, facial expression, and sound indicators per minute during pain tests, with a 95% confidence interval specified.
Numerical primary outcome results and group-specific enrollment are not reported in the registry record. The record also does not explain the three listed analyses, the statistical methods, or missing-data handling. Serious-event and other-event entries each list 49 at risk and 0 affected, with 0 deaths; no top serious-event terms are listed. The registry cautions that the arms are not a like-for-like control comparison.