Ketamine as a Rapid Treatment for Post-traumatic Stress Disorder (PTSD): Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Ketamine as a Rapid Treatment for Post-traumatic Stress Disorder (PTSD) (NCT00749203), a randomized phase 2 study. The primary outcome is Impact of Event Scale - Revised (IES-R).

2. Clinical Question

3. Trial Design

The registry describes a Phase 2 randomized, quadruple-masked crossover study, with 41 participants enrolled and study status recorded as completed. The two drug interventions were a single ketamine infusion and a single midazolam infusion. Ketamine was administered at 0.5 mg/kg over 40 minutes; midazolam was administered at 0.045 mg/kg over 40 minutes. The stated objective was to test whether a single intravenous ketamine dose decreases PTSD symptoms.

The primary outcome was measured 7 days after the first infusion. Its results include 19 participants in the Ketamine group and 15 in the Midazolam group. The registry explicitly notes that not all participants returned for the 1 week follow-up and completed the IES-R. Secondary outcomes were recorded at different follow-up times: the CAPS at 7 days after the first infusion, and QIDS-SR and MADRS at 24 hours after the first infusion. HVLT is listed among the secondary outcomes, but no result for it appears in the posted secondary results.

Although the design is identified as crossover, details needed to reconstruct the crossover analysis are not reported in the registry record. This includes the treatment sequence, whether a washout period was used, and how results from repeated treatment periods were handled. The record also does not report the trial’s original sample-size justification or a detailed statistical analysis plan. Those omissions limit how fully the posted group summaries can be connected to the intended analysis.

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.

First Infusion Day 1

no Infusion at Week 1

Reasons for not completing this period:

Second Infusion at 2 Weeks

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Not all participants returned for the 1 week follow up visit. There were 19 participants from the Ketamine group and 15 participants from the Midazolam group who returned for their followup visit and completed the IES-R at the 1 week follow up visit.

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 Impact of Event Scale - Revised (IES-R), measured over 7 days after first infusion.

The primary endpoint was the Impact of Event Scale - Revised (IES-R), a 22-item self-report questionnaire measuring PTSD symptoms. Items are rated on a 5-point scale from 0, “not at all,” to 4, “extremely.” The total score ranges from 0 to 88, with the endpoints described as “not at all” and “extremely.” The outcome is reported as a mean with a standard deviation, making it a continuous measure.

The IES-R is relevant to the stated study objective because it asks participants to report PTSD symptoms. The score at 7 days after the first infusion gives a measure of symptoms at that follow-up point; it is not, by itself, a measure of change from baseline. Baseline IES-R results and a baseline-adjusted analysis are not reported in the registry record. Therefore, the posted means should be read as follow-up scores, rather than as changes in symptoms.

The recorded primary outcome population is smaller than the total enrollment: 19 participants in the Ketamine group and 15 in the Midazolam group completed the IES-R at the 1 week follow-up. The record says some participants did not return, but does not give the reasons or a missing-data method. These registry entries matter because the reported endpoint summarizes those with observed follow-up results, and the record does not establish how their results relate to those who were not observed.

7. Results Posted in the Registry

• Midazolam: mean 36.32 versus 25.76 on control; difference 10.56 (95% CI -0.59 to 21.71), standardized effect d = 0.62; z-test p = 0.063.

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.

Clinician-Administered PTSD Scale (CAPS)

• 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:
  • Midazolam: mean 65.69 versus 54.00 on control; difference 11.69 (95% CI -1.78 to 25.16), standardized effect d = 0.56; z-test p = 0.089.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Midazolam and the control. The interval gives the range of effects that remain compatible with the data.

Quick Inventory of Depressive Symptomatology - Self Report (QIDS-SR)

• 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:
  • Midazolam: mean 11.30 versus 12.40 on control; difference -1.10 (95% CI -4.43 to 2.23), standardized effect d = -0.20; z-test p = 0.517.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Midazolam and the control. The interval gives the range of effects that remain compatible with the data.

Montgomery-Asberg Depression Rating Scale (MADRS)

• 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:
  • Midazolam: mean 10.10 versus 12.60 on control; difference -2.50 (95% CI -7.97 to 2.97), standardized effect d = -0.28; z-test p = 0.370.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Midazolam and the control. The interval gives the range of effects that remain compatible with the data.

The secondary outcomes cover PTSD symptoms, depressive symptoms, and verbal learning. The posted CAPS result is measured 7 days after the first infusion, while QIDS-SR and MADRS are measured 24 hours after the first infusion. HVLT is listed as a secondary outcome, but no result for it is posted among the secondary results. This means the secondary evidence is incomplete relative to the list of outcomes recorded in the registry.

Across the posted measures, the patterns are not uniform. The CAPS group means are lower for Ketamine than Midazolam, whereas the QIDS-SR and MADRS mean scores are higher for Ketamine. The secondary confidence intervals include zero for each posted comparison, and their unadjusted p-values do not provide strong evidence against a no-difference model. These results do not form a consistent pattern that independently confirms the primary IES-R contrast. They also address different constructs and, for some measures, a different follow-up time.

Secondary findings carry less weight than a prespecified primary result when many outcomes are examined without a reported multiplicity plan. Each additional comparison creates more opportunity for an apparently notable result by chance. The registry record lists several outcomes but does not report how the investigators prioritized them, whether a correction was planned, or whether the secondary analyses were exploratory. Their estimates and intervals remain informative descriptions, but the unadjusted results should not be treated as a set of confirmatory tests.

The secondary comparisons are also based on different numbers of observed participants and have their own uncertainty. They should not be combined informally into a single conclusion about all symptoms or functioning. Each outcome measures something different, and the registry record does not report a joint analysis or a prespecified rule for interpreting the measures together. In context, these outcomes offer supplementary evidence, not a substitute for a clear and sufficiently precise primary analysis.

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

• Clinician-Administered PTSD Scale (CAPS)
• Quick Inventory of Depressive Symptomatology - Self Report (QIDS-SR)
• Montgomery-Asberg Depression Rating Scale (MADRS)
• Hopkins Verbal Learning Test (HVLT)

9. Statistical Interpretation

10. Statistical Methods Explained

Continuous outcomes and group summaries. The primary outcome and the posted secondary measures are described as continuous scores. For each group, the registry reports a mean and standard deviation. A mean represents the arithmetic average of the observed scores. A standard deviation describes how dispersed those participant scores are around their group mean; it is not the uncertainty of the mean itself. In the primary results, the mean was 25.76 with a standard deviation of 19.4 for Ketamine, and 36.32 with a standard deviation of 13.73 for Midazolam.

Difference between means. The primary contrast is stated as Midazolam minus Ketamine. With that ordering, a positive value means the observed mean score was higher in the Midazolam group. The contrast of 10.56 is consistent with the difference between the posted means. The direction is useful for describing the data, but does not alone establish why the groups differed. In particular, it is not an adjusted estimate from a reported crossover model.

Confidence interval. A confidence interval expresses the range of effect estimates compatible with the observed data under the calculation’s assumptions. It shows precision as well as direction. A narrower interval indicates more precision; a wider interval indicates greater uncertainty. The primary 95% confidence interval ranges from slightly below zero to 21.71. Since it crosses zero, the posted summary-statistic comparison does not rule out no difference at the 95% confidence level. The interval also includes positive differences, so a range of values remains compatible with the observed summaries. A confidence interval does not give the probability that a particular effect is true.

Unadjusted p-value. The primary unadjusted p-value is 0.063. A p-value describes how unusual the observed data, or data more extreme, would be under a specified no-difference model and calculation assumptions. It is not the probability that the no-difference model is true, nor does it measure the size or importance of a difference. “Unadjusted” means the value is not adjusted for multiple comparisons. The registry record does not report a study-team analysis, so the posted p-value should be understood as an unadjusted summary-statistic comparison, not as evidence of a fully specified crossover analysis.

Standard deviations and uncertainty. The reported group standard deviations describe participant-to-participant score variation. The standard errors listed for the primary groups are 4.451 for Ketamine and 3.545 for Midazolam; these express uncertainty in the respective means under the calculation used. Standard errors and standard deviations answer different questions. A standard deviation describes the spread of individual observations, while a standard error describes how precisely a group mean is estimated. The registry record does not report a separate modeling approach for those standard errors.

Crossover design considerations. In general, crossover designs can use within-participant comparisons because participants receive more than one study treatment. Such analyses can account for the fact that measurements from the same person are related. The registry identifies this trial as crossover, but the posted outcome summaries are organized by Ketamine and Midazolam groups, and the record does not describe sequence, period, washout, within-person contrasts, or any model for correlated observations. It is therefore not possible to determine from the registry record whether the reported comparison uses the intended crossover structure or how treatment-period effects were handled.

Missing observations. The primary outcome results are based on participants who completed the follow-up questionnaire. The record notes that some participants did not return, but does not report why, whether the missingness differed by treatment sequence, or how missing data were handled in the original analysis. In general, missing outcomes can affect both precision and the representativeness of the observed group means. The consequences depend on why outcomes are missing and on the assumptions used to address them. No missing-data procedure is reported in the registry record, so its impact cannot be assessed from the posted summaries alone.

Planning calculations. The sample-size illustrations are based on the observed effect and use a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The calculations consider the stated fraction of the observed effect to detect. They are planning illustrations, not the trial’s original sample-size justification; that justification is not reported in the registry record. They also do not provide observed power or repair limitations in the actual data.

Multiplicity. Several secondary outcomes and follow-up times are listed. When multiple outcomes are examined, the chance of finding at least one apparently unusual result can increase if each is interpreted without adjustment. The registry does not report a multiplicity strategy or a hierarchy of endpoints. The individual unadjusted p-values should therefore be interpreted cautiously and alongside effect estimates, intervals, and the fact that the secondary outcomes are not independent replications of the primary question.

11. Confidence Intervals and Precision

The primary mean difference is 10.56 points, with a 95% confidence interval extending from just below zero to 21.71. The interval’s width indicates that the observed data are compatible with a range of possible differences, including a value close to no difference and appreciably larger positive differences under the Midazolam-minus-Ketamine ordering. The interval crossing zero means the summary-statistic comparison does not exclude no difference at this confidence level.

The point estimate is more specific than the evidence warrants if read alone. The result is based on 19 Ketamine and 15 Midazolam participants with observed IES-R scores, and variability within groups is substantial relative to the estimated difference. A confidence interval incorporates sampling uncertainty under its assumptions, but does not account automatically for missing outcomes, an unreported crossover model, or possible biases in who returned for follow-up.

Confidence intervals are not probability statements about the true effect. A 95% interval is produced by a procedure that, under its assumptions, would cover the target quantity in 95% of repeated applications. For this trial, the registry record does not report a study-team analysis or enough detail to verify that the interval reflects the crossover design. It is best read as an uncertainty summary for the posted group-level comparison rather than as a definitive interval from a documented trial model.

The breadth of the interval also means that a non-significant p-value should not be interpreted as proof that the groups were equivalent. Equivalence would require a prespecified margin and an analysis designed to assess it; neither is reported in the registry record. The available evidence is imprecise regarding the size of the contrast.

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 figures are participants per arm, not total event counts. They are illustrations based on the observed effect, with the effect to detect set at 100%, 75%, or 50% of that observed effect. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. These are planning assumptions for the posted illustrations; the trial’s own original sample-size assumptions and justification are not reported in the registry record.

The 80% power column gives the estimated participants per arm needed, under those assumptions, for an 80% chance of detecting the specified effect if that effect were present. The 90% power column uses a higher target chance of detection and therefore generally requires more participants per arm. The calculations are not observed power: they do not describe the probability that the completed trial detected an effect, and they do not add information to the observed outcome results.

The displayed planning scenarios show that smaller effects require more participants. For example, planning for 75% of the observed effect requires more participants per arm than planning for 100% of the observed effect; planning for 50% requires more still. This pattern reflects a general statistical principle: when the effect to be detected is smaller relative to outcome variability, more information is needed to distinguish it from random variation.

These figures should not be read as a recommendation for a future trial without considering its scientific question, design, outcome, missingness, and analysis plan. In particular, the calculation uses equal allocation between two arms, while the study is described as a crossover trial. The registry record does not explain how the planning illustration relates to the crossover design or to the trial’s original enrollment target.

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 = 10.560; pooled standard deviation σ = 17.152.
2. n = 2 × (1.96 + 0.842)² × 17.152² / 10.560² = 41.4, rounded up to 42 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 <- 10.56                      # observed difference in means
sigma <- 17.1515857503031                     # 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(749203)
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 = 42 (80% power), 56 (90% power)
 75% of observed effect: n per arm = 74 (80% power), 99 (90% power)
 50% of observed effect: n per arm = 166 (80% power), 222 (90% power)
power.t.test: 42.4 
Simulated power at n = 42 per arm: 0.802 (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. Multiplicity, Missing Data and Analysis Populations

The registry lists multiple outcomes, including a primary IES-R measure and secondary measures of PTSD symptoms, depression, and verbal learning. It does not report a multiplicity adjustment, a testing hierarchy, or a strategy for deciding which secondary comparisons should be considered confirmatory. When several outcomes or time points are tested, the chance of at least one apparently unusual result can rise if each is judged using an unadjusted threshold. The posted p-values should therefore be interpreted as individual, unadjusted results rather than as family-wise controlled evidence.

Missing follow-up is explicitly noted for the primary endpoint: not all participants returned for the 1 week visit, and the primary results include 19 participants in the Ketamine group and 15 in the Midazolam group. The registry record does not report why participants did not return, whether those missing differ from those observed, or how missing outcomes were treated in the study’s own analysis. It also does not report an intention-to-treat analysis, imputation, sensitivity analysis, or another missing-data approach.

The trial is identified as crossover, but details about treatment sequence, periods, washout, and correlation between repeated observations are not reported in the registry record. The posted group summaries do not show how within-participant data were incorporated. In addition, the record does not identify analysis populations or explain exclusions from any outcome analysis. These omissions limit assessment of whether the comparison reflects all randomized participants, only participants with observed outcomes, or another analysis set.

These are reporting limitations, not proof that a particular method was or was not used outside the registry record. They mean that the posted results do not allow readers to assess the original analysis choices, the handling of missing observations, or the consequences of testing multiple outcomes in full detail.

15. 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.

Most frequent serious adverse event terms

Serious events with the highest arm-level rate: blurred vision (39.5%), dizziness (36.8%), restlessness (34.2%), dry mouth (26.3%), nausea/vomiting (26.3%).

The registry’s serious adverse event figures list 38 participants at risk in the Ketamine group, with 33 affected, and 31 at risk in the Midazolam group, with 31 affected. The record lists zero deaths in each group. For the other adverse event category, it lists zero affected among 38 at risk for Ketamine and zero among 31 at risk for Midazolam. These counts are reported as recorded and should not be interpreted as a direct estimate of comparative risk without further definitions and analysis.

The registry also lists serious adverse event terms with percentages: blurred vision, 39.5%; dizziness, 36.8%; restlessness, 34.2%; dry mouth, 26.3%; nausea/vomiting, 26.3%; and fatigue, 26.3%. The record does not explain in the registry entries whether these percentages represent participants, events, or another reporting denominator, nor does it give a comparative analysis for each term. The percentages should therefore be read as registry-listed frequencies, not as evidence that one treatment caused a particular event more often.

Because the study is crossover, interpreting exposure and risk by group also depends on details such as treatment periods and attribution. Those details are not reported in the registry record. The safety counts describe the recorded data but do not establish comparative safety or causation.

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

The posted primary results describe IES-R scores at 7 days after the first infusion. The mean score was lower in the Ketamine group than in the Midazolam group, and the unadjusted mean difference was 10.56 points in the Midazolam-minus-Ketamine direction. The 95% confidence interval includes values on both sides of zero, and the unadjusted p-value was 0.063. These results show a difference in the observed group means, but the uncertainty is substantial and the interval does not rule out no difference.

That description is not the same as establishing that a treatment works or does not work. The registry record does not report a study-team statistical analysis, an analysis accounting for the crossover design, or a method for handling participants without follow-up scores. The group summaries also do not report baseline IES-R scores or change from baseline. Consequently, the posted results cannot by themselves establish a causal treatment effect, quantify change from baseline, or show how outcomes would have differed for participants who did not complete follow-up.

Nor does a p-value above 0.05 demonstrate equivalence. The registry does not report an equivalence margin or a design intended to establish equivalence. The broad interval leaves uncertainty about the magnitude and direction of the underlying contrast. Likewise, the observed difference should not be treated as a precise estimate simply because it is a single number.

The secondary results provide additional outcome summaries but do not resolve these limitations. They cover different measures and time points, include unadjusted comparisons, and do not show a uniform pattern across the posted endpoints. The record does not report a plan for interpreting multiple comparisons together. The safety counts and event terms also describe recorded events rather than proving comparative risks or causes.

The appropriately bounded conclusion is that the posted follow-up scores were lower on average in the Ketamine group for the primary measure, while the estimated contrast remains imprecise and important design and analysis details are absent from the registry record. The result should be understood as a description of the available outcome data, not as a definitive treatment conclusion.

17. Why This Trial Matters Statistically

This trial is statistically informative because its registry record places several common interpretation challenges side by side. It is described as a randomized crossover study, yet the posted primary results are group means and standard deviations, with no reported details about treatment sequence, period effects, or within-participant modeling. The distinction matters: a design label alone does not show how the analysis used the design or whether the relevant dependencies were accounted for.

The primary endpoint also illustrates why an estimate should be read together with its uncertainty. The observed group means differ, but the confidence interval extends across zero and the p-value is 0.063. Reporting the point estimate alone could overstate certainty; treating the p-value as a binary verdict would discard information about the range of contrasts compatible with the observed data.

Follow-up completion is another important statistical issue. The registry says not all participants returned for the primary 1 week assessment, and the endpoint summaries use fewer participants than the total enrollment. Without a reported missing-data strategy, readers cannot assess how the observed results might relate to the missing outcomes. This is relevant to both validity and precision.

Finally, the trial lists multiple secondary outcomes, but no multiplicity plan or study-team analyses are reported. The record therefore highlights how outcome selection, missingness, analysis populations, and design-specific modeling shape the strength of inference. Its statistical value lies not only in the observed scores, but also in showing why transparent reporting of the analysis is essential for interpreting them.

18. 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 is incomplete primary follow-up. The registry states that not all participants returned for the 1 week visit; the IES-R results include 19 participants in the Ketamine group and 15 in the Midazolam group. Reasons for non-return and the handling of missing scores are not reported in the registry record. The observed means may therefore represent only those with completed follow-up, and the potential effect of missingness cannot be assessed.

A second limitation is the lack of detail about the crossover analysis. The registry identifies the design as crossover but does not report treatment sequence, period effects, washout, within-participant contrasts, or the statistical model used. The available group-level summaries do not establish whether the analysis accounted for correlations between repeated observations. This makes it difficult to assess whether the reported contrast fully reflects the design.

The registry record does not report baseline scores, change-from-baseline results, a sample-size justification, or a study-team statistical analysis. It also does not report which analysis populations were used or a multiplicity strategy for the several outcomes and time points. Secondary results are not posted for every listed measure. These gaps limit interpretation of both the primary comparison and the breadth of secondary evidence.

The primary comparison is based on a relatively limited observed outcome population and has a confidence interval that includes zero. The interval therefore leaves substantial uncertainty about the contrast. Safety figures are reported without a comparative statistical analysis or enough detail about the percentages’ denominators and attribution. These constraints do not determine the direction of bias, but they restrict what conclusions can be drawn from the registry results.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Ketamine as a Rapid Treatment for Post-traumatic Stress Disorder (PTSD) — NCT00749203.
• Registry record last updated 2018-02-14; status last verified 2018-02.
• Results first posted 2018-02-14.
• 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.

22. Record Summary

The registry describes a completed Phase 2 randomized, quadruple-masked crossover trial with 41 participants enrolled. The interventions were a single intravenous infusion of ketamine at 0.5 mg/kg and a single intravenous infusion of midazolam at 0.045 mg/kg, each infused over 40 minutes.

The primary outcome was the IES-R score 7 days after the first infusion. The posted means were 25.76 for Ketamine and 36.32 for Midazolam, based on 19 and 15 participants, respectively. The unadjusted mean difference was 10.56, with a 95% confidence interval extending from just below zero to 21.71 and an unadjusted p-value of 0.063.

The record notes missing 1 week follow-up and does not report a detailed analysis plan, crossover-specific modeling, or a missing-data method. Secondary measures and safety results are also posted, but the record does not report a multiplicity strategy or study-team statistical analyses. The results are best read as descriptive group summaries with substantial uncertainty.