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 An Efficacy and Safety Study of Long Acting Injectable Risperidone and Oral Risperidone in Participants With Schizophrenia or Schizoaffective Disorder (NCT00992407), a randomized phase 4 study. The primary outcome is Change From Baseline in Personal and Social Performance (PSP) Scale Score at Week 52.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT00992407 |
| Phase | Phase 4 |
| Condition | Schizophrenia |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 75 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Janssen Korea, Ltd., Korea |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned participants with schizophrenia or schizoaffective disorder. The registry lists schizophrenia as a condition and describes the intended population as including both disorders. The primary-outcome population was defined as the intent-to-treat population: randomized participants who received at least one dose of study medication and fulfilled all inclusion and exclusion criteria. Participant characteristics, eligibility details beyond that definition, and the number meeting this analysis-population definition are not reported in the registry record.
Intervention
The intervention was long-acting injectable risperidone. The record identifies this as a drug intervention but does not report the dose, injection schedule, treatment duration by participant, or other treatment-management details.
Comparator
The active comparator was oral risperidone tablets. The record does not report the tablet dose, schedule, or whether treatment could be adjusted during the study. The study was open-label, with no masking reported.
Primary question
The primary outcome was change from baseline in Personal and Social Performance (PSP) Scale score at Week 52. The study therefore asked whether the two risperidone treatment groups differed in change in measured personal and social functioning over that period. The registry record does not report a single numerical between-group estimate, confidence interval, or p-value for this primary question, so the size and precision of any difference cannot be assessed from the posted results described in the record.
3. Trial Design
This was a randomized, parallel-group, active-controlled Phase 4 study. It compared long-acting injectable risperidone with oral risperidone tablets in participants described as having schizophrenia or schizoaffective disorder. The allocation was randomized, and masking was listed as none, making the study open-label. The record names Janssen Korea, Ltd., Korea, as sponsor.
The registry reports enrollment of 75 participants and a completed study. The start is listed as 2007-12 and primary completion as 2010-12. Those dates describe the overall study record; they do not establish how long any individual participant was followed or treated. The primary outcome was assessed at Week 52, with the stated timeframe of baseline and Week 52.
The record identifies the two interventions but gives no arm-specific treatment descriptions. Dose, dosing frequency, treatment adjustments, adherence procedures, and concomitant-care rules are not reported in the registry record. The number randomized to each group and the number completing follow-up are also not reported in the registry record. Enrollment should not be treated as the analysis sample size, because the primary analysis population has its own stated eligibility and treatment conditions.
Other listed outcomes include symptom severity, social and emotional functioning, and neurocognitive measures at Week 52. The registry lists 22 outcome measures and 5 analyses, but the meaning and correspondence of those counts to particular outcomes are not reported in the registry record. It also does not report the randomization procedure, allocation concealment, masking of outcome assessors, or a detailed statistical analysis plan. These omissions limit evaluation of how the planned design was implemented.
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 | Risperidone Injection | Risperidone Tablets |
|---|---|---|
| STARTED | 37 | 38 |
| Treated | 20 | 25 |
| COMPLETED | 6 | 14 |
| NOT COMPLETED | 31 | 24 |
Reasons for not completing this period:
| Reason | Risperidone Injection | Risperidone Tablets |
|---|---|---|
| Protocol Violation | 2 | 1 |
| Lost to Follow-up | 3 | 3 |
| Adverse Event | 3 | 2 |
| protocol Violation & Adverse events | 2 | 4 |
| Other | 2 | 0 |
| Loss of follow-up & Adverse events | 2 | 1 |
| Study medication not administered | 17 | 13 |
Analysis population for the primary outcome, as defined in the registry: Intent-to-treat (ITT) population included all randomized participants who received at least one dose of study medication and fulfilled all inclusion and exclusion criteria.
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: "N" (number of participants analyzed) signifies the participants evaluable for this measure.
| Characteristic | Unit | Risperidone Injection | Risperidone Tablets | Total |
|---|---|---|---|---|
| Participants analysed | 17 | 24 | 41 | |
| Age, Continuous | years | 36.9 (SD 10.5) | 32.8 (SD 9.4) | 34.5 (SD 10.0) |
| Sex: Female, Male: Female | Participants | 8 | 8 | 16 |
| Sex: Female, Male: Male | Participants | 9 | 16 | 25 |
6. Primary Endpoint
The registry lists the primary outcome as Change From Baseline in Personal and Social Performance (PSP) Scale Score at Week 52, measured over Baseline and Week 52.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was change from baseline in Personal and Social Performance (PSP) Scale score at Week 52. The PSP is described as assessing dysfunction in four domains: socially useful activities, personal and social relationships, self-care, and disturbing and aggressive behavior. A total score is formed from those domains. The scale ranges from 1 to 100 and is divided into 10 equal intervals for rating degree of difficulty, from 1 (absent) to 6 (very severe) in each domain. The record describes scores from 71 to 100 as indicating mild difficulty, scores from 31 to 70 as varying degrees of disability, and scores less than or equal to 30 as functioning so poorly as to require intensive supervision.
A change score compares a participant’s measurement at follow-up with the baseline measurement. This can focus the outcome on how measured functioning changed during the study rather than on the Week 52 score alone. Comparing changes between randomized groups can address whether the groups’ observed trajectories differ, subject to the analysis methods and data available.
The registry record does not report the mean change in either group, the between-group contrast, its uncertainty, or a p-value. The direction and magnitude of the observed primary-outcome change therefore cannot be described from the posted results in this record. The record also does not state a threshold for interpreting a change as clinically important.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The design sets up a comparison between two active risperidone formulations, with change in PSP score at Week 52 as the primary outcome. Randomized allocation is intended to make the groups comparable on average at the start of a trial. Open-label conduct means participants and study personnel were not masked according to the registry. For an outcome that includes ratings of functioning, awareness of treatment assignment could potentially influence behavior, reporting, or assessment. The record does not report whether outcome assessors were masked or what steps were used to limit such influences.
The registry gives the endpoint definition and analysis-population description, but does not report numerical primary-outcome results. A group mean change, a between-group difference, a confidence interval, and a p-value are not reported in the registry record. As a result, the posted information does not establish the direction, magnitude, or statistical precision of the primary comparison. It is not possible to infer whether the groups’ results were similar or different from the design description alone.
The enrollment of 75 describes the number enrolled, not necessarily the number included in the primary analysis. The stated intent-to-treat population includes randomized participants who received at least one dose and met all inclusion and exclusion criteria. The count in that population, and the number with observed Week 52 measurements, are not reported in the registry record. Without those counts and a description of missing-data handling, the extent to which the endpoint analysis may depend on incomplete follow-up cannot be assessed.
The listed secondary outcomes cover symptoms, social functioning, emotional and social functioning, and neurocognitive tests. Their presence indicates that the study considered outcomes beyond the primary PSP measure, but their numerical results and analysis details are not reported in the registry record. The number of listed outcomes and analyses does not by itself reveal which comparisons were prespecified, which were emphasized, or whether adjustment for multiple testing was used.
Accordingly, the defensible statistical reading is limited: the registry describes a randomized, open-label comparison and its intended primary measure, but the record does not provide the primary comparison needed to quantify the observed result. Safety counts are available for adverse-event categories, but they do not substitute for the missing efficacy estimate. No conclusion about treatment benefit, equivalence, or lack of difference follows from the absence of a reported primary estimate.
9. Statistical Methods Explained
The primary endpoint is a continuous measure, and the registry identifies the target summary as a mean with standard deviation as the dispersion measure. A mean describes the central value of a group’s measurements; a standard deviation describes how spread out individual measurements are around that mean. These statistics describe a group distribution, but neither one alone provides the estimated difference between treatment groups or its precision.
For a change-from-baseline outcome, each participant’s follow-up value is considered relative to that participant’s baseline value. A group mean change can describe the average observed change among participants included in the analysis. A between-group contrast in mean change is a separate quantity and is ordinarily needed to express the comparative result. The registry record does not report either group’s mean change, the contrast, or standard deviations for the primary endpoint. A recalculated unadjusted comparison is therefore not available from the posted information.
General statistical context: a confidence interval gives a range of values compatible with the data and the analysis assumptions at a stated confidence level. Its width reflects precision: a narrower interval indicates greater precision than a wider interval. A point estimate without an interval can conceal substantial uncertainty, while an interval without a prespecified clinical threshold does not by itself establish whether a difference matters to participants. Neither a confidence interval nor a p-value for the primary endpoint is reported in the registry record.
General statistical context: a p-value measures how unusual the observed data, or data more extreme, would be under a specified null hypothesis and model. It does not measure the probability that the null hypothesis is true, the size of an effect, or clinical importance. Interpretation requires the estimate and its uncertainty as well as knowledge of the analysis plan. The primary p-value and the method used to calculate it are not reported in the registry record.
Randomization is a design feature that can reduce systematic differences between groups at baseline, but the label alone does not show whether allocation was concealed or whether the groups were balanced on relevant characteristics. The randomization method, allocation concealment, and baseline outcome distributions are not reported in the registry record. Open-label conduct is stated; masking was listed as none. The record does not describe whether a model adjusted for baseline score or other covariates, or whether the primary comparison used an unadjusted method.
The trial is described as parallel-group, so participants were assigned to one of the two treatment groups rather than being described as crossing between treatments. The particular statistical model, assumptions, treatment of repeated measurements, and handling of deviations from the assigned treatment are not reported in the registry record. General statistical context: an analysis of change scores and an analysis of follow-up scores adjusted for baseline can target related but not identical quantities and can have different precision. The registry does not identify which approach was used.
The record describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation, and a normal approximation; the effect to detect is described as a stated fraction of the observed effect. Such values are planning illustrations, not observed power and not evidence about the trial’s original design. The registry record does not report the numerical planning estimates or the observed effect needed to interpret them. The original sample-size justification and its assumptions are not reported in the registry record.
General statistical context: over-dispersion occurs when variability in the data exceeds what a model assumes. If it is ignored, standard errors may be too small and confidence intervals too narrow, making apparent precision greater than warranted. This concept is relevant only if the chosen model and data structure make it relevant; the registry record does not report a model or any assessment of over-dispersion. It would therefore be inappropriate to claim that over-dispersion was present or that the analysis addressed it.
General statistical context: missing outcomes can reduce precision and can bias a treatment comparison when the chance of missingness is related to participant status or outcome. Methods such as likelihood-based models, imputation, or sensitivity analyses rely on assumptions that should be described and evaluated. The registry record does not report the amount or pattern of missing primary-outcome data, the method used to handle missingness, or sensitivity analyses. The absence of those details means the robustness of the primary comparison cannot be evaluated.
The registry lists multiple outcomes and analyses. General statistical context: when many hypotheses are tested, the chance of at least one apparently notable result can increase unless the analysis plan controls or addresses multiplicity. The record does not report whether a hierarchy, correction, or other multiplicity strategy was used. No inferential result for a secondary outcome is included in the information available in the registry record, so no interpretation of those comparisons is warranted.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 22 outcome measures and 5 analyses, including the primary PSP change outcome and secondary measures of symptoms, functioning, and neurocognition. Those counts signal that the study considered multiple measurements, but they do not explain how the analyses were organized or which comparisons were designated confirmatory. The analysis plan, ordering of hypotheses, and any adjustment for multiple comparisons are not reported in the registry record.
Multiplicity matters because examining many outcomes or comparisons can make isolated results harder to interpret. General statistical context: a prespecified hierarchy or a multiplicity adjustment can help control the chance of false-positive findings across a family of tests. The registry does not identify whether either approach was used. Without the analysis plan and the corresponding numerical results, it is not possible to distinguish primary inference from exploratory findings.
The stated primary analysis population includes all randomized participants who received at least one dose of study medication and fulfilled all inclusion and exclusion criteria. This definition is narrower than simply saying all enrolled participants and does not establish the final number analyzed. The number randomized, the number meeting the stated population definition, and the number with Week 52 outcome measurements are not reported in the registry record.
Missing-data procedures are also not reported in the registry record. The amount and reasons for missing measurements, participant withdrawals, and sensitivity analyses are not described. This matters because results based only on participants with observed follow-up can differ from results under other assumptions about missing outcomes. The record does not support a judgment about whether missing data were negligible or whether a particular method adequately addressed them.
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 |
|---|---|---|---|
| Risperidone Injection | 0 | 20 | 0.0% |
| Risperidone Tablets | 0 | 25 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 2% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Risperidone Injection | 11 of 20 |
| Risperidone Tablets | 13 of 25 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Risperidone Injection | Risperidone Tablets |
|---|---|---|---|
| Akathisisa | Nervous system disorders | 2 of 20 | 4 of 25 |
| dystonia | Nervous system disorders | 1 of 20 | 2 of 25 |
| Weight increased | Investigations | 2 of 20 | 1 of 25 |
| dysarthria | Nervous system disorders | 1 of 20 | 1 of 25 |
| Anxiety | Psychiatric disorders | 2 of 20 | 0 of 25 |
| Upper respiratory tract infection | Infections and infestations | 0 of 20 | 2 of 25 |
| Muscle rigidity | Musculoskeletal and connective tissue disorders | 2 of 20 | 0 of 25 |
| sedation | Nervous system disorders | 0 of 20 | 1 of 25 |
| Dizziness | Nervous system disorders | 0 of 20 | 1 of 25 |
| headache | Nervous system disorders | 0 of 20 | 1 of 25 |
The registry reports serious adverse-event figures for the two treatment groups. For Risperidone Injection, 0 serious adverse events were reported among 20 participants at risk; for Risperidone Tablets, 0 were reported among 25 participants at risk. These are the counts in the registry record, not evidence that no serious events occurred outside the recorded data or that risk was absent.
For other adverse events, the record lists 11 affected participants among 20 at risk in the injection group and 13 among 25 at risk in the tablet group. These figures are counts of participants affected, not counts of all event episodes. The record does not provide event-specific terms in the serious-event listing, which has no terms listed. It also does not describe the severity, timing, duration, or relationship to treatment for the other adverse events.
Death counts are not reported in the registry record. The adverse-event figures are descriptive and do not, on their own, establish whether one treatment is safer than the other. The groups have different reported numbers at risk, and no statistical comparison or uncertainty measure for these safety counts is reported in the registry record. Safety interpretation is further limited by the absence of detailed event descriptions and follow-up information.
12. What the Result Does, and Does Not, Mean
The registry record supports a description of the study question and design: randomized allocation, open-label conduct, two active risperidone formulations, and a primary assessment of change in PSP score at Week 52. It also specifies the intended analysis population and the domains measured by the PSP. These details clarify what the study was designed to evaluate.
They do not establish the size or direction of the primary result. The group-level changes, comparative estimate, confidence interval, and p-value are not reported in the registry record. Without these quantities, the statistical evidence for a difference between the treatment groups cannot be characterized. The lack of a numerical comparison is not evidence that the treatments had equal outcomes, nor is it evidence that one performed better.
Even if a comparative estimate were available, its interpretation would depend on precision, the analysis population, missing data, the statistical model, and whether the size of the difference was meaningful for the outcome. The record does not report a threshold for clinically important PSP change. Thus, a statistical distinction and a clinically important distinction could not be treated as interchangeable.
The safety counts describe recorded adverse-event categories, but do not offer a complete account of event type, severity, attribution, or timing. They should be read as descriptive counts rather than as a standalone comparative safety analysis. The registry’s serious-event counts and other-event counts do not resolve the missing primary efficacy result.
Overall, the record allows readers to identify the intended comparison and the limits of the reported information. It does not support a conclusion that either treatment improves functioning, that the treatments are equivalent, or that one treatment is safer. Those conclusions require results and analysis details that are not reported in the registry record.
13. Why This Trial Matters Statistically
This study is statistically informative as an example of the difference between a clearly stated research question and a fully interpretable result. The design identifies the target population, active comparator, primary measure, and assessment time. Randomized allocation and a defined analysis population provide important context for understanding how a comparative trial is intended to work.
At the same time, an endpoint definition is not an outcome estimate. The PSP description explains what was measured, but without group changes and a between-group contrast it is impossible to judge the observed magnitude or precision of the comparison. This distinction matters for clinical research readers: a registry entry can document a study’s structure while still leaving the central statistical result unavailable.
The open-label design is also relevant to interpretation. For an outcome involving ratings of social and personal functioning, awareness of treatment assignment could potentially affect experience or assessment. This is a general concern rather than evidence that bias occurred in this study. The registry does not report whether assessors were masked or what procedures were used to reduce that risk.
Finally, multiple listed outcomes make transparent reporting of the analysis plan important. Readers need to know which contrasts were primary, how missing outcomes were handled, and whether multiplicity was addressed before interpreting results across a set of measures. Those details are not reported in the registry record. The study therefore illustrates why design labels and outcome definitions should be considered alongside effect estimates, uncertainty, population counts, and analysis methods.
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.
Several limitations specific to this study constrain interpretation of the registry record. The main limitation is the absence of a reported numerical primary-outcome comparison. The registry identifies change in PSP score at Week 52 as the primary outcome but does not report group means, the between-group estimate, a confidence interval, or a p-value. No single comparative conclusion can be drawn without those results.
The record reports enrollment of 75 but does not give the number randomized to each treatment group, the number meeting the stated intent-to-treat definition, or the number contributing Week 52 measurements. This prevents assessment of how much of the enrolled sample entered the primary analysis and whether follow-up differed between groups. Reasons for missing data and the method used to handle it are not reported in the registry record.
The study was open-label, with masking listed as none. The record does not say whether outcome assessors were masked. This is relevant because the primary outcome evaluates functioning across behavioral and social domains. The randomization method and allocation concealment are also not reported, limiting assessment of how allocation was implemented.
Intervention details are sparse: doses, schedules, treatment adjustments, adherence, and treatment exposure are not reported in the registry record. The statistical model, baseline adjustment, assumptions, and sensitivity analyses are likewise not described. The record does not report a clinical-importance threshold for PSP change or a multiplicity strategy for the many listed outcomes. These omissions are distinct from evidence of a flaw; they mean that readers cannot evaluate these features from the registry record.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: An Efficacy and Safety Study of Long Acting Injectable Risperidone and Oral Risperidone in Participants With Schizophrenia or Schizoaffective Disorder — NCT00992407.
- Registry record last updated 2014-03-11; status last verified 2014-02.
- Results first posted 2014-03-11.
- 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.
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18. Record Summary
The registry describes a completed, randomized, open-label, parallel-group Phase 4 study sponsored by Janssen Korea, Ltd., Korea. It enrolled 75 participants with schizophrenia or schizoaffective disorder and compared long-acting injectable risperidone with oral risperidone tablets. The study start is listed as 2007-12 and primary completion as 2010-12.
The primary outcome was change from baseline in PSP Scale score at Week 52. The registry defines an intent-to-treat population and lists secondary symptom, functioning, and neurocognitive outcomes. It also reports adverse-event counts for serious and other events in each group.
A numerical primary-outcome comparison, analysis methods, missing-data procedures, and multiplicity handling are not reported in the registry record. The available information therefore describes the study’s question and design more fully than its comparative statistical result.