The Efficacy of Neural Stimulation in Individuals With Schizophrenia: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for The Efficacy of Neural Stimulation in Individuals With Schizophrenia (NCT05746494), a randomized na study. The primary outcome is The State Social Paranoia Scale (SSPS).

2. Clinical Question

The study asked whether active anodal transcranial Direct Current Stimulation (tDCS), compared with sham stimulation, was associated with a different short-term change in state paranoid ideation among individuals with schizophrenia spectrum disorders. Its stated broader purpose was to understand the relationship between psychotic symptoms and social functioning, and to examine whether brain stimulation could improve symptoms and daily functioning.

The primary outcome is a short-term symptom measure, not a direct measure of daily functioning. The registry lists four secondary outcomes intended to assess related social judgments, interpretations, and hostility. Results therefore address the recorded stimulation visits and measured outcomes; they do not by themselves establish effects on broader functioning or on outcomes that were not reported.

3. Trial Design

The registry record describes a randomized, double-blind crossover study with 50 participants enrolled. In a crossover design, participants receive both conditions at different times, and randomization assigns the order. One sequence received active anodal tDCS first and sham tDCS later; the other received sham first and active later. Each visit involved 40 minutes of stimulation in two 20-minute sessions, followed by behavioral testing. The record describes a washout of about 1 week between stimulation visits.

The posted outcome data are labeled Active Visit and Sham Visit, with 50 observations for each primary outcome condition. These are visit-level summaries from the crossover study; they should not automatically be interpreted as results from two separate groups of 50 different people. The scrambled-sentences outcome has 49 observations per visit, while the other listed primary and secondary summaries have 50 per visit.

The trial status is completed. The registry lists the study start as 2022-11-21 and primary completion as 2024-08-01. The intervention is listed as a device, and the phase is listed as NA. The registry record does not report details of the randomization procedure, how blinding was maintained or assessed, the allocation ratio, or the study's own sample-size justification. It also does not report enough information to determine how sequence, period, or carryover effects were handled in the analysis.

These design features matter when interpreting the comparison. Because each participant was scheduled to experience both conditions, measurements within a participant may be related. An analysis that uses this relationship can differ from one reconstructed only from separate visit means and standard deviations. The posted sponsor analysis is identified as ANOVA for the primary outcome, but further model details are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as The State Social Paranoia Scale (SSPS), measured over The assessment was completed before the stimulation and 30 minutes after completion of the active/sham stimulation.

The primary endpoint is the mean change score on the State Social Paranoia Scale (SSPS), defined as the score before stimulation minus the score after stimulation. Assessments were completed before stimulation and 30 minutes after completion of active or sham stimulation. The scale asks participants to rate agreement with 20 statements, including statements about perceived hostility or being isolated, using a 5-point Likert scale. Total scores range from 20-100, with higher scores representing higher state paranoid ideation.

A change score is used to describe how a participant's measured score differs between the pre-stimulation and post-stimulation assessments. With the registry's pre-minus-post definition, a positive score indicates that the pre-stimulation value was higher than the post-stimulation value. The posted group means are 9.72 for Active Visit and 3.9 for Sham Visit. These summaries describe average change, not the distribution of individual participant changes.

The SSPS was selected as the primary outcome because the study's stated question includes psychotic symptoms and the scale specifically measures state paranoid ideation. The endpoint is therefore closely connected to the short-term symptom question. It does not directly measure all aspects of social functioning, daily functioning, or longer-term outcomes. The registry record does not report a threshold for a change considered meaningful to participants, nor does it describe how the endpoint was selected as primary beyond its listing in the record.

7. Results Posted in the Registry

• Active Visit: mean 9.72 versus 3.90 on control; difference 5.82 (95% CI 0.66 to 10.98), standardized effect d = 0.44; z-test p = 0.027.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

The Trustworthiness Task

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Active Visit: mean 0.07 versus -0.18 on control; difference 0.25 (95% CI -0.17 to 0.67), standardized effect d = 0.23; z-test p = 0.246.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Visit and the control. The interval gives the range of effects that remain compatible with the data.

The Scrambled-sentences Task (SST)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Active Visit: mean 0.46 versus 0.49 on control; difference -0.03 (95% CI -0.14 to 0.08), standardized effect d = -0.11; z-test p = 0.602.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Visit and the control. The interval gives the range of effects that remain compatible with the data.

The Hostility Scale of the Personality Inventory for DSM-5 (PID-5-HS)

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Active Visit: mean 9.42 versus 11.30 on control; difference -1.88 (95% CI -4.85 to 1.09), standardized effect d = -0.25; z-test p = 0.214.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Active Visit and the control. The interval gives the range of effects that remain compatible with the data.

Across the four secondary outcomes, the recalculated estimates do not show a consistent direction or a common pattern of clear separation between Active Visit and Sham Visit. Each recalculated confidence interval includes zero. The sponsor-reported p-values are not uniformly aligned with those summary-statistic comparisons. Taken together, the secondary results do not provide a consistent extension of the primary result across the related measures.

These outcomes cover different constructs: trustworthiness judgments, interpretation of scrambled sentences, hostile-intention judgments, and hostility measured with a personality-inventory scale. They are related to social judgments or hostility, but they are not interchangeable measures of the primary SSPS construct. A difference on one measure would not automatically establish a difference on another, and the group results do not show how each participant's outcomes across measures were related.

The secondary tests carry less confirmatory weight because the registry record does not report a multiplicity adjustment or a detailed plan for interpreting the family of secondary comparisons. When several outcomes are tested, isolated small p-values can occur by chance more often than when a single outcome is tested. The record also does not report whether these secondary endpoints were ordered, whether any were designated as key secondary endpoints, or how missing observations were handled across tests.

Accordingly, the secondary outcomes are best treated as additional, exploratory context for the primary comparison rather than as independent confirmation of it. The sponsor-reported p-values should be read alongside the recalculated estimates and their uncertainty, not in isolation. The differences between reported and recalculated tests further limit the strength of conclusions that can be drawn from the secondary set without fuller model descriptions.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• The Trustworthiness Task
• The Scrambled-sentences Task (SST)
• The Ambiguous Intentions Hostility Questionnaire (AIHQ)
• The Hostility Scale of the Personality Inventory for DSM-5 (PID-5-HS)

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: SSPS change is reported as a mean and standard deviation for each visit. A mean describes the average observed score or change in a group, while a standard deviation describes the spread of participant values around that mean. The Active Visit mean change is 9.72 with a standard deviation of 14.61; the Sham Visit mean change is 3.9 with a standard deviation of 11.56. These standard deviations indicate that individual values vary around their respective averages, but they do not reveal the full shape of the distributions.

What does a mean difference represent?

The recalculated mean difference compares the Active Visit mean with the Sham Visit mean. For the primary outcome, the estimate is 5.82. A positive value means the mean pre-minus-post change is larger at the Active Visit than at the Sham Visit. The estimate is a difference in average change scores, not a percentage change and not the change experienced by every participant. The underlying individual outcomes may differ from the group average.

What does the confidence interval add?

The 95% confidence interval for this recalculated difference is 0.656 to 10.98. In general, a confidence interval communicates the uncertainty in an estimate: narrower intervals indicate greater precision, while wider intervals indicate less precision. Under the assumptions of the method, a confidence interval is constructed so that intervals from repeated comparable samples would contain the underlying value at the stated rate. It is not a statement that there is a 95% probability that this particular interval contains the true value. Interpretation also depends on whether the calculation's assumptions fit the design and data.

How should the p-values be read?

The sponsor-reported primary analysis is an ANOVA with p = 0.023. The unadjusted recalculation from the posted summary statistics gives p = 0.027. A p-value describes how unusual data at least as incompatible with a null comparison would be under the specified model if that null were true. It is not the probability that the null hypothesis is true, and it does not measure the size or importance of an effect. The two p-values differ because they come from distinct analyses. The registry record does not report enough detail about the ANOVA model to reproduce it from the posted summaries.

Why does the crossover structure matter?

In a crossover study, each participant receives both conditions. If a person's outcomes under active and sham stimulation are correlated, a paired analysis can use the within-person comparison. A recalculation based only on separate means, standard deviations, and visit counts does not have the individual paired differences or their variability. It therefore cannot represent all the information available in participant-level crossover data. The sponsor's primary analysis is reported as ANOVA, but its model specification, treatment of sequence and period, and handling of possible carryover are not reported in the registry record. No particular modeling choice should be assumed.

What does over-dispersion mean in general?

For continuous outcomes, large variability relative to the mean difference can make estimates less precise. More generally, over-dispersion describes data that vary more than a statistical model expects. A model that does not account for excess variability can understate uncertainty. The registry record does not report an over-dispersion assessment for these outcomes, and the concept should not be taken as a finding about this trial.

What can the secondary analyses tell us?

The registry lists four secondary outcomes, each with visit means and standard deviations, a recalculated mean difference and confidence interval, and a sponsor-reported test. For these recalculations, the confidence intervals are based on summary statistics, and the reported p-values are unadjusted. The registry does not state whether or how the sponsor adjusted for making multiple comparisons. When several outcomes are examined, the chance of observing at least one small p-value can increase even when there is no underlying difference. This is why secondary findings without a reported multiplicity plan deserve less confirmatory weight than a prespecified primary analysis.

All recalculated estimates are simple unadjusted re-calculations from posted summary statistics. They are useful for describing the arithmetic comparison visible in those summaries, but they do not replace the sponsor's analysis or recover unavailable participant-level details. They should be read alongside the design, the registry's reported analysis, and the limitations of the available outcome information.

11. Confidence Intervals and Precision

The primary recalculated mean difference is 5.82, with a 95% confidence interval from 0.656 to 10.98. This interval gives a range of values compatible with the summary-statistic estimate under the recalculation's assumptions. Its width shows that the point estimate should not be treated as exact: values near the lower and upper ends imply meaningfully different magnitudes of average change. Because the interval's lower endpoint is above zero, it is consistent with a positive Active Visit minus Sham Visit difference under this calculation.

Precision and clinical meaning are separate issues. A confidence interval does not identify a threshold that matters to participants, and the registry record does not report such a threshold for the SSPS change score. Nor does the interval show how results might vary across other settings or populations. It quantifies sampling uncertainty for the calculation, not every source of uncertainty in the study.

The crossover design adds an important qualification. The summary-statistic recalculation uses the visit means, standard deviations, and counts, but does not include the within-participant relationship between active and sham measurements. A paired analysis may have different precision because it uses that relationship. The registry reports an ANOVA p-value of 0.023 for the primary comparison, but does not provide an ANOVA confidence interval or enough model details to derive one. The recalculated interval should therefore be understood as belonging to the unadjusted summary-statistic comparison, not as a reconstruction of the sponsor's full model.

The same caution applies to secondary intervals. An interval that includes zero is compatible with a range of differences in either direction under the recalculation, and does not prove that the conditions are equivalent. The intervals express uncertainty in estimated group differences; they do not by themselves resolve the effects of multiple testing, missing observations, or model choices that are not documented in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning estimates are participants per arm, not total events. They are illustrations based on the observed effect and are not the original trial's design calculation. The assumptions listed for the illustrations are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. For each displayed scenario, the effect to detect is the stated fraction of the observed effect.

The 80% power column gives the illustrative number of participants per arm that would yield an 80% chance of detecting the specified effect under those assumptions, if that effect were the true one. The 90% power column gives the corresponding illustrative number for a 90% chance. These are planning concepts: power is the probability of detecting a specified effect under a stated design and model, not a probability that a result is true.

The scenarios consider planning for 100%, 75%, and 50% of the observed effect. Smaller effects require more participants to detect under the same assumptions, which is why the estimated counts increase as the target fraction decreases. These figures are sensitive to the assumed effect size and should not be interpreted as the number actually enrolled in this study. The trial's own original sample-size justification and design assumptions are not reported in the registry record.

These are not observed power estimates. They are forward-looking planning illustrations based on the observed effect and the stated assumptions. The registry record's crossover design also means these simple per-arm figures may not describe the design considerations used in the trial's original planning.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = 5.820; pooled standard deviation σ = 13.174.
2. n = 2 × (1.96 + 0.842)² × 13.174² / 5.820² = 80.4, rounded up to 81 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- 5.82                      # observed difference in means
sigma <- 13.1735663356587                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(5746494)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 81 (80% power), 108 (90% power)
 75% of observed effect: n per arm = 143 (80% power), 192 (90% power)
 50% of observed effect: n per arm = 322 (80% power), 431 (90% power)
power.t.test: 81.4 
Simulated power at n = 81 per arm: 0.797 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Analyses Reported by the Sponsor

For the primary SSPS outcome, the registry reports an ANOVA with p = 0.023. The recalculation from the posted visit means and standard deviations gives an unadjusted mean difference of 5.82, a 95% confidence interval from 0.656 to 10.98, and p = 0.027. The two p-values are close and lead to the same broad statistical reading, but they are outputs of different analyses.

The recalculation is a simple comparison of posted summary statistics. It does not reproduce an ANOVA model, and it cannot use participant-level information or the within-person relationship between visits. The registry identifies the sponsor's method as ANOVA, but does not report model specification, covariates, period or sequence terms, or details of missing-data handling. The numerical difference between the p-values should therefore not be attributed to a particular modeling choice without those details.

The record does not flag a discrepancy between the posted result and the recalculation. The sponsor-reported analysis remains the registry's stated analysis, while the recalculation offers a transparent, unadjusted comparison based on the reported summaries. Neither p-value measures clinical importance, and the sponsor's reported p-value does not supply the missing model details needed to fully evaluate the analysis.

15. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary outcome and four secondary outcomes, with eight outcome measures and eight analyses posted overall. It does not report a multiplicity adjustment, a hierarchy for testing endpoints, or a rule for controlling the chance of false-positive findings across analyses. In general, testing multiple outcomes increases the opportunity for at least one apparently notable result to arise by chance. Without a reported adjustment or testing hierarchy, secondary p-values should not be interpreted as if each were the only test performed.

The record does not report a missing-data strategy, an analysis population definition, or whether all randomized participants were included in each analysis. The enrollment is 50; posted summaries show 50 observations per visit for the primary SSPS outcome and most secondary outcomes, while the scrambled-sentences outcome has 49 observations per visit. The reason for the lower count on that outcome is not reported in the registry record. These figures alone do not establish whether observations were missing, excluded, or unavailable for another reason.

Because this is a crossover trial, evaluation of the analysis would also benefit from information on how the sponsor handled the paired nature of the data, period and sequence, and possible carryover. The registry identifies ANOVA for the primary outcome and two-sided t-tests for the secondary outcomes, but does not report the full model specifications or whether those analyses accounted for the crossover structure. It does not report interim analyses or a detailed statistical analysis plan.

These omissions do not establish that the analyses were inappropriate; they mean that the registry record does not contain enough information to assess several important analytic choices. The posted estimates and tests can be described as recorded, while conclusions about missingness, multiplicity control, or the exact population represented by each analysis remain limited.

16. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry records 0 serious adverse events among 50 participants at risk for the Active Visit and 0 among 50 at risk for the Sham Visit. It also records 0 deaths for each visit. The registry's other adverse-event category records 0 among 50 at risk at each visit.

These are counts recorded for the two visit conditions. They describe what appears in the registry record; they do not show that no adverse events of any kind occurred outside the categories or reporting period captured there. The record does not list serious adverse-event terms, and it does not provide further detail about event definitions, collection procedures, severity, timing, or attribution. With zero events recorded in each category, a comparative risk estimate cannot be inferred from these counts alone.

Safety counts should be considered separately from the symptom outcome results. The absence of recorded events in these categories is not proof that risk is absent, and the information does not support a broader safety conclusion beyond the posted figures.

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

The primary result describes a short-term difference in average SSPS change scores between active and sham visits. The recalculated mean difference is 5.82 in the direction of a larger pre-minus-post change at the Active Visit. The registry-reported ANOVA gives p = 0.023, while the unadjusted recalculation gives p = 0.027. These findings indicate statistical evidence of a difference under the reported and recalculated approaches, with the recalculation's confidence interval extending from 0.656 to 10.98.

That result does not establish how important the difference is to participants. The registry record does not report a minimum meaningful change threshold for the SSPS. Nor does the result tell whether a short-term change persists, whether it translates into improved daily functioning, or whether it applies beyond the participants and circumstances represented in the study. The assessment occurred 30 minutes after completion of stimulation, so the reported primary outcome is a near-term measure.

The comparison also should not be interpreted as a simple parallel-group trial. Participants were assigned to receive both active and sham stimulation in one of two sequences. The posted summary-statistic recalculation cannot account for within-participant correlation, and the registry does not describe the sponsor's ANOVA model in enough detail to resolve how crossover features were treated.

The secondary outcomes offer no uniform corroborating pattern, and their unadjusted results are less persuasive in the absence of reported multiplicity handling. The safety record contains zero serious adverse events and zero deaths in each visit category, but those counts are not proof of no risk. Overall, the posted data support a description of a short-term measured difference, not a definitive claim about clinical benefit, longer-term effects, or safety.

18. Why This Trial Matters Statistically

This trial is statistically interesting because it uses a randomized crossover design to compare active and sham stimulation within a study in which participants experience both conditions. A crossover can make within-person comparisons informative, but the statistical analysis needs to reflect the relationship between observations from the same participant. The registry's summary statistics allow a simple mean comparison, while the sponsor-reported primary result is an ANOVA. The difference between those approaches highlights why model details matter when interpreting registry results.

The primary outcome is a continuous change score, making the mean difference and confidence interval useful for understanding both direction and precision. The point estimate alone would not convey the uncertainty in the comparison. Here, the interval has a positive lower endpoint but also spans a range of possible magnitudes, so the estimate should be read as uncertain rather than exact.

The record also illustrates the distinction between a primary result and a set of secondary tests. Several related outcomes can add context, but without a reported multiplicity plan they do not carry the same confirmatory weight as a prespecified primary analysis. Differences between sponsor-reported tests and summary-statistic recalculations reinforce the value of transparent analysis plans and model descriptions.

Finally, planning illustrations based on an observed effect are not the same as a trial's original sample-size justification. Recognizing that distinction prevents retrospective planning calculations from being mistaken for design documentation or evidence of observed power.

19. 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 provides limited detail for evaluating the analysis beyond the named methods and reported summaries. It does not report the ANOVA specification, whether the crossover structure was modeled with participant-level effects, how period or sequence was considered, or whether possible carryover was assessed. The summary-statistic recalculation cannot recover the paired differences or their covariance.

The record does not report the sample-size justification used when the study was designed, an analysis population definition, a missing-data method, or an interim-analysis plan. Although most posted outcomes have 50 observations per visit and the scrambled-sentences outcome has 49 per visit, the reason for that difference is not reported in the registry record. Multiplicity handling for the secondary outcomes is also not reported.

The primary measure captures state paranoid ideation shortly after stimulation. The registry does not provide a meaningful-change threshold or report longer-term follow-up for this endpoint. Its stated broader interest in social and daily functioning should not be mistaken for direct evidence about every aspect of functioning: the posted primary outcome is the SSPS, and the secondary outcomes are task or scale measures.

The study enrolled 50 participants, and the results are limited to the outcomes and assessments recorded. The registry record does not describe participant characteristics in detail, the reasons for any nonparticipation or missing measurements, or how generalizability was assessed. Zero serious adverse events and deaths are recorded in each visit category, but event definitions and collection details are not reported. These limitations constrain interpretation without establishing that any particular bias or problem occurred.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: The Efficacy of Neural Stimulation in Individuals With Schizophrenia — NCT05746494.
• Registry record last updated 2025-02-26; status last verified 2025-02.
• Results first posted 2025-02-26.
• 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.

23. Record Summary

The University of Texas at Dallas sponsored this completed, randomized, double-blind crossover study of tDCS in individuals with schizophrenia or schizoaffective disorder. The registry lists an enrollment of 50 and describes randomized sequences of active anodal and sham visits separated by a washout of about 1 week.

The primary outcome was pre-minus-post change in SSPS score, assessed before stimulation and 30 minutes after stimulation. The Active Visit mean was 9.72 and the Sham Visit mean was 3.9. The reported ANOVA p-value was 0.023; the unadjusted summary-statistic recalculation estimated a mean difference of 5.82 with a 95% confidence interval from 0.656 to 10.98 and p = 0.027.

Four secondary outcomes and adverse-event counts are also recorded. The registry does not report several details needed to fully assess the analysis, including the full crossover model, missing-data handling, and multiplicity procedures. The posted results describe a short-term outcome comparison and do not establish clinical importance or longer-term effects.