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 Impact of Inflammation on Reward Circuits, Motivational Deficits and Negative Symptoms in Schizophrenia (NCT03818516), a na na study. The primary outcome is Effort-Expenditure for Rewards Task (EEfRT) Score.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03818516 |
| Phase | NA |
| Condition | Schizophrenia |
| Allocation | Not applicable (single group) |
| Design model | Single Group |
| Masking | None (open label) |
| Enrollment | 12 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Emory University |
| Results posted | Yes |
2. Clinical Question
Population
The registry summary describes recruitment of persons with schizophrenia or schizoaffective disorder. The intervention description specifies medically stable participants with schizophrenia and a range of insulin resistance. The record lists schizophrenia as the condition.
Intervention
Participants underwent an oral glucose tolerance test (OGTT). The study summary says the test was used to examine the hypothesis that insulin resistance drives inflammation. The record does not describe a separate treatment intervention.
Comparator
There was no comparison group listed. The study is described as a single-group study, with no randomized allocation and no masking. Participants therefore are not divided in the record into a treatment arm and a like-for-like control arm.
Primary question
The primary endpoint was the Effort-Expenditure for Rewards Task (EEfRT) score, expressed as the proportion of hard-task choices. It was assessed at baseline and Hour 1. The record does not report numerical endpoint results or an analysis relating the score to insulin resistance or inflammation.
The stated scientific aim concerns the relationship between insulin resistance and inflammation in people with schizophrenia or schizoaffective disorder. The listed primary endpoint, however, is a measure of task choices intended to assess motivation. These describe related aspects of the study rationale but are not interchangeable outcomes: the EEfRT score records choice behavior during a reward task, while the summary's hypothesis concerns insulin resistance and inflammation.
The record also lists secondary measures of motor speed, visual scanning, processing speed, and mood. It does not give numerical results for these measures. As a result, the clinical question can be described from the protocol summary and endpoint definitions, but the posted registry information does not allow readers to assess whether motivation, cognition, mood, insulin resistance, or inflammation changed or were associated with one another.
3. Trial Design
This was a completed, single-group study sponsored by Emory University. The registry lists an enrollment of 12 and gives the study start as 2020-08-31 and primary completion as 2022-03-01. The phase is listed as NA. Allocation is listed as NA, masking as NONE, and the study model as SINGLE GROUP.
The intervention was an oral glucose tolerance test. The arm description states that medically stable participants with schizophrenia and a range of insulin resistance would have the test. The brief summary describes recruitment of persons with schizophrenia or schizoaffective disorder. These descriptions are not identical, so the record does not support a more specific account of the final enrolled population than the registry wording.
The primary endpoint was the EEfRT score at baseline and Hour 1. Secondary outcomes listed are the Finger Tapping Task score, Trail Making Test Part A score, Digit Symbol Substitution Task score, and Profile of Mood States Brief score. The registry lists 20 outcome measures overall, but the record does not provide numerical results for the primary endpoint or these named secondary measures.
A single-group design can describe measurements made in the enrolled group, but it does not provide a concurrent control group for separating changes associated with the test from changes over time or other influences. No randomized comparison is listed. The registry record does not report the protocol's sample-size justification, a detailed statistical analysis plan, or the handling of repeated measurements. It also does not describe whether all enrolled participants completed each assessment.
The study status is COMPLETED, but completion status alone does not establish that results are available in the registry record. In this case, the record includes outcome definitions and safety counts but no numerical primary-outcome summary or analysis. Thus, the design and intended measurements can be described, while the study's estimated outcome effects cannot be interpreted from these registry entries.
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.
Before assignment: This was an optional substudy underpowered to identify relationships between changes in inflammatory and metabolic markers pre- and post-OGTT with reward circuitry or motivational deficits. These analyses are thus exploratory and would serve as preliminary data for future research proposals.
Overall Study
| Stage | Oral Glucose Tolerance Test (OGTT) |
|---|---|
| STARTED | 12 |
| COMPLETED | 11 |
| NOT COMPLETED | 1 |
Reasons for not completing this period:
| Reason | Oral Glucose Tolerance Test (OGTT) |
|---|---|
| Exclusion due to positive UDS (THC) test | 1 |
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: Participants who met all screening requirements.
| Characteristic | Unit | Oral Glucose Tolerance Test (OGTT) |
|---|---|---|
| Participants analysed | 11 | |
| Age, Categorical: <=18 years | Participants | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 11 |
| Age, Categorical: >=65 years | Participants | 0 |
| Age, Continuous | years | 35.36 (SD 12.42) |
| Sex: Female, Male: Female | Participants | 1 |
| Sex: Female, Male: Male | Participants | 10 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 |
| Race (NIH/OMB): Asian | Participants | 0 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 |
| Race (NIH/OMB): Black or African American | Participants | 7 |
| Race (NIH/OMB): White | Participants | 4 |
| Race (NIH/OMB): More than one race | Participants | 0 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 |
| Region of Enrollment: United States | participants | 11 |
6. Primary Endpoint
The registry lists the primary outcome as Effort-Expenditure for Rewards Task (EEfRT) Score, measured over Baseline, Hour 1.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | Standard Deviation |
| Unit | proportion of hard-task choices |
| Endpoint classification | Continuous Endpoint |
The primary endpoint is the Effort-Expenditure for Rewards Task (EEfRT) score, reported as the proportion of hard-task choices. The task is described as a multitrial game used to assess motivation. At each trial, participants choose between a high-effort and a low-effort task to pursue a monetary reward. Completing the selected task involves repeated manual button presses to raise a virtual bar to its top. Reward amounts for the high-effort option vary, while those for the low-effort option remain constant; trials also vary in the probability of winning the selected reward.
The first 50 trials are used for analysis. The score is calculated from hard-task choices across all levels of probability. The endpoint description states that lower percentages of hard-task choices indicate decreased motivation. This makes the measure a behavioral indicator of willingness to select a more effortful option in the task, rather than a direct measure of motivation in every setting of daily life.
The endpoint is listed at baseline and Hour 1. The registry does not report the score at either time, a change between times, or an estimated association with insulin resistance or inflammation. It also does not state how those repeated measurements were modeled. The definition explains what the score is intended to represent, but without numerical results readers cannot determine the observed pattern or its precision.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry record identifies a primary endpoint and its assessment times, but it does not report a primary EEfRT mean, standard deviation, change, confidence interval, or statistical test. Consequently, there is no posted numerical estimate from which to judge the direction, size, or precision of an outcome pattern. The record cannot establish from the primary endpoint whether hard-task choices were more or less frequent at Hour 1 than at baseline.
This absence is important when interpreting a completed study. A status of COMPLETED indicates the registry's study status; it does not supply the missing outcome estimate. Similarly, the description of the hypothesis about insulin resistance and inflammation states the study's rationale, not a finding. The primary EEfRT score measures task choices, and the registry does not report a numerical result linking that measure to inflammation or insulin resistance.
The registry lists an enrollment of 12, but the safety record lists 11 participants at risk for the serious and other adverse-event counts. Those entries should be read as recorded, without assuming why the denominators differ or which participants contributed to each efficacy assessment. The record does not report the analysis population for the EEfRT endpoint, the amount of missing endpoint data, or whether any participants were excluded from an analysis.
Confidence intervals describe a range of values compatible with an estimated effect under the assumptions of the analysis. Their width conveys precision: wider intervals indicate greater uncertainty, while narrower intervals indicate greater precision. No primary-outcome estimate or confidence interval is reported in the registry record, so precision cannot be assessed. The same limitation applies to statistical significance: without a reported test statistic or p-value, no claim about statistical evidence for a change is supported.
The study has a single-group design, not a randomized comparison. Even if a before-and-after estimate were available, a change over time in this group would not by itself distinguish the effect of the OGTT from other time-related or measurement influences. Here, the numerical endpoint result is also absent, so even a descriptive within-group change cannot be assessed from the registry record.
The safety entries report zero serious adverse events, zero other adverse events, and zero deaths among 11 participants at risk in each listed category. These are event counts in the registry record, not a complete estimate of the probability of harm and not evidence that no adverse events could occur. The record does not provide details about event definitions or follow-up duration for these counts.
Overall, the registry information supports a description of the study design, outcome definition, and recorded safety counts. It does not support a conclusion about the primary endpoint's observed value, whether it changed, how precisely it was estimated, or whether the study hypothesis was supported.
9. Statistical Methods Explained
The registry describes a continuous primary measure summarized as a mean, with standard deviation as its dispersion measure. A mean gives the average score within the group under analysis. A standard deviation describes how spread out individual scores are around that mean; it is not the same as the uncertainty in the estimated mean. The record does not provide the primary endpoint's mean or standard deviation, so neither the average score nor its variability can be evaluated.
What would a baseline-to-Hour-1 estimate represent?
The endpoint is listed at baseline and Hour 1, so an analysis might describe the score at each assessment or estimate change across assessments. Those are different summaries. A pair of means describes the levels at each time, while a change estimate describes the within-group difference across times. The registry record does not report either type of estimate and does not specify the model or test used for repeated measurements. No particular analysis should therefore be attributed to the study.
In general, repeated observations from the same participant are related rather than independent. An analysis that accounts for this relationship can differ from one that treats every observation as unrelated. The appropriate method depends on the design, data completeness, and analysis plan. Those details are not reported in the registry record, so the handling of within-participant dependence cannot be assessed.
How should uncertainty be read?
A confidence interval expresses uncertainty around an estimated quantity, conditional on the model and its assumptions. It gives a range of values compatible with the observed data and analysis method; it is not a guarantee that the true value lies in that range. A narrower interval generally indicates more precision than a wider interval. Since no primary estimate or interval is reported, there is no basis for describing the precision of the EEfRT result.
A p-value is one way of describing how unusual data would be under a specified null hypothesis and statistical model. It does not measure the size or clinical importance of an effect, and it does not give the probability that the null hypothesis is true. The registry record does not report a primary-outcome p-value or the statistical test to which one might apply. Therefore, no statement about statistical significance is warranted.
What does the single-group structure allow?
In general, a single-group study can describe observed measurements within that group. It does not provide a concurrent control group to distinguish an intervention-related effect from changes that could occur over time, effects of repeated testing, or other influences. The record lists no randomized allocation and no comparator arm. Thus, even if outcome estimates were reported, the design would need to be considered when interpreting any before-and-after pattern. In this registry record, the lack of numerical results prevents assessment of such a pattern in the first place.
The description of an OGTT as the intervention does not mean the study is a randomized trial comparing treatments. The record presents a one-group test procedure and a hypothesis about insulin resistance and inflammation. It does not state that participants were assigned to contrasting levels of insulin resistance, or that the OGTT itself was compared with a separate control condition.
How should the planning illustrations be understood?
The planning assumptions describe illustrations based on an observed effect, not the study's original design. They use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation; the effect to detect is expressed as a stated fraction of the observed effect. Such calculations are prospective planning illustrations: they describe the sample size that might be required under those assumptions for a future two-arm study. They are not observed power for this single-group study, and they do not show that the study was designed with those assumptions.
There is an important design distinction between the planning setup and the registered study structure. The study is listed as single-group, whereas the illustrations assume equal allocation between two arms. That mismatch means the calculations should not be treated as a description of the completed study's allocation or as evidence about its ability to detect an effect. The registry record does not report the original sample-size justification or a protocol-level power calculation.
In general, planning calculations depend on assumptions about the target effect, outcome variability, significance threshold, allocation, and analysis. If those assumptions do not match a study's design or the data-generating process, the resulting sample-size estimate may not be informative for that study. These illustrations also do not replace an effect estimate with an uncertainty interval. No specific planning sample size or primary effect estimate is reported in the registry record.
Why can over-dispersion matter?
For count outcomes, over-dispersion means that observed variability is greater than a simple count model would expect. If not accommodated, standard errors can be too small and intervals or tests can appear more certain than warranted. This is a general statistical consideration for count data, not a reported feature of this study's primary endpoint. The primary measure is a proportion of hard-task choices, summarized as a mean with a standard deviation, and the record does not report an over-dispersion assessment or a model for that score.
For a proportion derived from repeated choices, the distribution and dependence of the underlying choices can affect how uncertainty is estimated. General methods may model individual choices, summarize scores at the participant level, or use other approaches. The registry record does not specify which approach was used. It also does not report details about transformations, covariate adjustment, or robustness checks. These possibilities should be treated as methodological considerations, not as claims about analyses conducted in the study.
In short, the posted registry information defines the primary measure and some planning assumptions but does not give the outcome estimates or enough analysis detail to reconstruct the statistical method. The study's numerical result, uncertainty, and analysis choices are not reported in the registry record.
10. Multiplicity, Missing Data and Analysis Populations
The registry lists 20 outcome measures and 0 analyses. The named secondary outcomes include the Finger Tapping Task score, Trail Making Test Part A score, Digit Symbol Substitution Task score, and Profile of Mood States Brief score. The record identifies the EEfRT score as primary, but does not provide numerical results for it or the secondary measures.
When a study assesses multiple outcomes or conducts multiple statistical tests, the chance of at least one apparently notable result can increase. Multiplicity procedures can address that issue, but the choice depends on the planned family of hypotheses and analysis strategy. No multiplicity adjustment, testing hierarchy, or prespecified approach is reported in the registry record. The listing of multiple outcome measures alone does not show that all were analyzed or that any particular adjustment was used.
Information about missing data is also not reported in the registry record. The record does not state how many EEfRT observations were available at baseline or Hour 1, whether participants missed assessments, or how missing measurements were handled. It does not describe an intention-to-treat population, a per-protocol population, or another analysis population for the endpoint. The enrollment figure and the safety denominators do not establish the number contributing to any efficacy analysis.
Without these details, readers cannot assess whether missingness could have influenced the outcome estimate or whether analyses across outcomes were controlled for multiplicity. No assumptions about imputation, exclusions, or selective reporting can be justified from the information recorded.
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 |
|---|---|---|---|
| Oral Glucose Tolerance Test (OGTT) | 0 | 11 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Oral Glucose Tolerance Test (OGTT) | 0 of 11 |
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 |
|---|---|
| Oral Glucose Tolerance Test (OGTT) | 0 of 11 |
The registry's safety entries list the Oral Glucose Tolerance Test group with 11 participants at risk for serious adverse events and 0 affected. For other adverse events, the entry also lists 11 at risk and 0 affected. Deaths are listed as 0. No serious adverse-event terms are listed.
These figures are counts recorded for the safety categories; they do not establish that the intervention has no risks. A zero count means no event was recorded in that category among the participants represented by the listed at-risk count. It does not rule out events that were not captured, events outside the recorded follow-up, or uncommon events that a study of this size could not characterize reliably.
The registry does not report the safety follow-up period, detailed event definitions, or whether all events were actively collected in the same way. The safety denominator is 11, while the listed enrollment is 12; the record does not explain that difference. It would be inappropriate to infer a reason or substitute one denominator for the other.
The safety counts should therefore be read narrowly as the adverse-event information entered in the registry, not as a comprehensive evaluation of safety or a comparison with another group.
12. What the Result Does, and Does Not, Mean
The registry record documents a completed single-group study focused on an oral glucose tolerance test and motivation-related task behavior in people described as having schizophrenia or schizoaffective disorder. It specifies an EEfRT score at baseline and Hour 1 as the primary endpoint and lists several secondary cognitive and mood measures. These details clarify what the investigators intended to measure.
The posted record does not report numerical results for the primary endpoint. It therefore does not show the average proportion of hard-task choices, the variation across participants, or whether the score differed between baseline and Hour 1. It also does not report a confidence interval, p-value, or model-based estimate. No conclusion about the direction, size, statistical evidence, or precision of a primary outcome result can be drawn from the registry entries.
The study's stated hypothesis is that insulin resistance drives inflammation. That hypothesis is part of the study summary, not a reported finding. The EEfRT measures choices in a reward task, and the registry does not provide a numerical link between those choices, insulin resistance, and inflammation. The secondary outcome names likewise do not establish that any cognitive or mood measure changed.
The zero counts for recorded adverse events and deaths are descriptive safety entries, not proof of no risk. The single-group design also does not provide a randomized comparator for attributing any potential change to the test. In addition, the analysis population, missing-data handling, and statistical plan are not reported in the registry record.
Accordingly, the meaning of this record is primarily methodological and descriptive: it identifies the study structure, intended endpoint, assessment timing, and recorded safety counts. It does not establish whether the hypothesis was supported or whether any measured outcome improved, worsened, or remained unchanged.
13. Why This Trial Matters Statistically
This study is statistically notable for the distinction between a stated mechanistic hypothesis and the primary outcome actually listed. The summary describes an interest in whether insulin resistance drives inflammation, while the primary endpoint is the proportion of hard-task choices on the EEfRT. A clear interpretation requires keeping these constructs separate: a task-based motivation measure is not itself a direct measurement of inflammation.
The single-group structure also matters. A study without a randomized comparison can describe the enrolled group's measurements, but it cannot use a concurrent control arm to distinguish changes associated with the study procedure from changes related to time, retesting, or other influences. This design feature limits causal interpretation independently of sample size.
The registry record illustrates why outcome definitions and numerical results must be read together. The endpoint description is detailed, including the first 50 trials used for analysis and the task's varying reward and winning-probability features. Yet no numerical primary result is posted. A detailed definition helps readers understand what a score would mean, but it cannot substitute for an estimate, an uncertainty interval, and a description of the analysis.
Planning assumptions also need to be separated from the completed study design. The planning illustrations assume two arms with equal allocation and a normal approximation, whereas the registered study is single-group. Such illustrations can help frame hypothetical future planning, but they do not establish the original design, observed power, or evidence of an effect in this study.
Finally, the record lists multiple outcomes but no analyses and does not describe missing-data handling or multiplicity control. These omissions prevent evaluation of how outcome selection, incomplete measurements, or multiple testing may have affected any conclusions. The case underscores the value of transparent results and analysis reporting alongside clear endpoint definitions.
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 for interpretation is that the registry record does not report numerical results for the EEfRT primary endpoint. Without the mean, standard deviation, change estimate, interval, or test result, the primary outcome's pattern and precision cannot be assessed. Numerical results for the listed secondary outcomes are also not reported in the record.
The study is listed as single-group, with allocation NA and masking NONE. No like-for-like control comparison is described. This limits the ability of the design to separate a change over time from an effect attributable to the study procedure. The registry record also does not explain the assessment schedule beyond the primary endpoint's baseline and Hour 1 timeframe or describe the statistical treatment of those measurements.
The population wording differs between the brief summary, which mentions schizophrenia or schizoaffective disorder, and the intervention description, which specifies participants with schizophrenia. The record does not provide further detail about the enrolled diagnostic composition or the range of insulin resistance. The listed enrollment is 12, while the safety entry lists 11 at risk; the reason for this difference is not reported in the registry record.
Other limitations include the absence of a reported sample-size justification, detailed statistical analysis plan, analysis population, missing-data approach, and multiplicity strategy. Although the record lists 20 outcome measures, it lists 0 analyses. The registry does not clarify which measures were analyzed or how outcomes were selected for reporting. These omissions prevent a full assessment of analytic decisions and potential sources of uncertainty.
The safety information is also limited to event counts and at-risk figures without reported follow-up duration or detailed event definitions. The record's completion status does not resolve these gaps. These limitations concern what can be interpreted from the registry record and should not be mistaken for evidence that particular analyses or events did or did not occur outside it.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Impact of Inflammation on Reward Circuits, Motivational Deficits and Negative Symptoms in Schizophrenia — NCT03818516.
- Registry record last updated 2024-05-02; status last verified 2024-04.
- Results first posted 2024-05-02.
- 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
NCT03818516 is a completed, single-group study sponsored by Emory University. The registry lists an enrollment of 12, a start date of 2020-08-31, and a primary completion date of 2022-03-01. The study investigated an oral glucose tolerance test in the context of a hypothesis concerning insulin resistance and inflammation.
The primary endpoint was the EEfRT score, expressed as the proportion of hard-task choices, at baseline and Hour 1. Secondary outcomes included motor, cognitive, and mood measures. The registry lists 20 outcome measures and 0 analyses, but does not report numerical results for the primary endpoint or the named secondary outcomes.
The safety record lists 11 participants at risk for serious and other adverse events, with 0 affected in each category and 0 deaths. The record does not report a comparator group, a detailed analysis plan, missing-data handling, or a multiplicity approach. The available information describes the design and intended measurements but does not establish an outcome effect or its precision.