Does Pharmacological Treatment of Attention Deficit Hyperactivity Disorder (ADHD) in Adults Enhance Parenting Performance?: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Does Pharmacological Treatment of Attention Deficit Hyperactivity Disorder (ADHD) in Adults Enhance Parenting Performance? (NCT01127607), a randomized phase 4 study. The primary outcome is Dyadic Parent-Child Interaction Coding System (DPICS) - Behavior Counts.

2. Clinical Question

3. Trial Design

The registry record describes a phase 4, randomized, double-masked, parallel trial sponsored by Florida International University. The study began in 2010-11, reached primary completion in 2012-07, and is listed as completed. Total enrollment was 38.

The trial compared blinded lisdexamfetamine with a placebo pill described as identical in appearance to the active medication. The medication was given at the individual participant’s optimal dose, determined during a medication optimization portion of the study. The record also describes groups of participants prescribed 30mg, 50mg, or 70mg in period 1 for safety reporting. Those period 1 dose groups are distinct from the endpoint comparison, which is described as medication versus placebo at the end of period II.

The primary endpoint was collected at the end of period II in a between-subjects comparison. Each participant completed both a homework task and a non-academic task, making task situation a within-subjects feature; medication group was between subjects. The endpoint description reports 10 participants in the medication group and 13 in the placebo group. It attributes the total endpoint sample of 23 to three participants who dropped out before completing this assessment and one participant who completed other endpoint measures but not the DPICS assessment.

The registry record does not report further details about the randomization procedure, allocation concealment, the duration of each period, or how the medication and placebo periods were sequenced. It also does not report the prespecified statistical model or the analysis population used for the primary comparison. Those details should not be inferred from the trial label alone.

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: Participants first stabilized on LDX in 3 week open label trial starting at 30mg + increasing by 20mg/week until optimal dose was found. Those unable to tolerate LDX or not responsive to it were discontinued. 38 enrolled; 8 dropped out due to adverse events + 3 were lost to follow up in med phase, leaving 27.

Phase I (Within Subjects)

Phase II (Between Subjects)

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Task situation (homework vs. non-academic) was within-subjects; all participants completed both types of interactions. Medication was between subjects.

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: Adult participant was first stabilized on LDX during a 3 week open label titration. 11 participants dropped out during med titration phase (8 due to adverse events and 3 lost to follow-up; a 12th dropped out after group assignment but prior to receiving blinded phase II medication.

6. Primary Endpoint

The registry lists the primary outcome as Dyadic Parent-Child Interaction Coding System (DPICS) - Behavior Counts, measured over study endpoint- end of period II (between subjects trial).

The primary endpoint is the Dyadic Parent-Child Interaction Coding System (DPICS) - Behavior Counts. It measures the number of parent and child behaviors observed while they interact during a five minute homework task and a 10 minute non-academic task. The interactions were recorded and later coded by trained observers, and average numbers of behaviors per group were computed. The endpoint is described as a mean with standard deviation, and its unit is behaviors.

Observed behavior is relevant to the study question because it records interactions during structured tasks rather than relying only on a participant’s account of parenting. In general, a coded observation can describe specific behaviors that occur in a defined setting. It does not, by itself, establish how often those behaviors occur in other settings or how they relate to broader family functioning.

All participants completed both task types, while medication group was the between-subjects comparison. The registry record gives the combined endpoint sample as 23: 10 in the medication group and 13 in the placebo group. It does not report the group means, standard deviations, a contrast between groups, or a confidence interval. Therefore, the size and precision of any group difference in behavior counts are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry record describes a randomized, double-masked, parallel trial, but it does not report the statistical methods used to analyze the primary endpoint. In particular, the analysis model, method for comparing groups, handling of task situation, covariate adjustment, and approach to missing data are not reported in the registry record. The following concepts are general explanations of how such endpoint data can be interpreted; they do not describe a method confirmed for this trial.

What does a mean describe?

In general, a mean is an average of the measured values in a group. For this endpoint, the measured values are counts of parent and child behaviors coded during interactions. A mean can summarize the typical level of recorded behavior in a group, but it can hide variation among participants and differences between task situations. The registry record says average numbers of behaviors per group were computed and identifies standard deviation as the dispersion measure. It does not report the actual means or standard deviations.

Why does dispersion matter?

In general, the standard deviation describes how spread out individual observations are around a group mean. If observations vary substantially, the mean alone gives an incomplete account of the data. A group comparison needs both an estimate of the difference and information about uncertainty. The registry record’s endpoint description identifies the intended descriptive measure and dispersion, but does not include their values or a between-group estimate.

What does a confidence interval communicate?

In general, a confidence interval expresses uncertainty around an estimated quantity, such as a difference between group means. A narrower interval indicates greater precision under the method used; a wider interval indicates less precision. An interval also helps readers assess which values are reasonably compatible with the data and analysis. No confidence interval for the primary endpoint is reported in the registry record, so its precision cannot be assessed.

Why does the task structure affect analysis?

The endpoint includes observations from a homework task and a non-academic task, and each participant completed both. In general, repeated measurements from the same participant may be related, so an analysis that treats them as independent can misrepresent uncertainty. A statistical model can account for within-participant structure, but the appropriate approach depends on the research question and the data. The record identifies task situation as within-subjects and medication as between-subjects; it does not report how that structure was handled analytically.

In general, an analysis might estimate an overall group contrast, task-specific contrasts, or both. These answer different questions. An overall contrast summarizes the groups across task contexts, while task-specific contrasts describe comparisons separately for each context. If effects differ across tasks, a single average may not capture that pattern. The registry record does not report whether either type of contrast was calculated or how the behavior categories were treated.

What can a p-value establish?

In general, a p-value measures how compatible the observed data are with a specified statistical model and null hypothesis. It is not a measure of the size or practical importance of an effect, and it does not give the probability that a treatment works. Interpretation requires the estimate, uncertainty, analysis assumptions, and context—not the p-value alone. No primary endpoint p-value or test is reported in the registry record.

Likewise, a recalculation from summary statistics would require the relevant group summaries and a clearly defined contrast. Those endpoint summaries are not reported, so no recalculated comparison can be made. No sponsor analysis is available in the registry record for comparison with a recalculation.

How should planning estimates be read?

In general, a sample-size calculation describes how many participants might be needed under specified assumptions about the effect, variability, allocation, and significance level. Such a planning illustration is not an observed trial result and is not observed power. The record describes an illustration based on a fraction of the observed effect, a two-sided significance level of 0.05, equal allocation, and a normal approximation. No numerical planning results are stated in the registry record presented for this analysis, and the illustration should not be mistaken for the trial’s own design justification.

The record does not report the statistical plan, whether analyses were prespecified, whether interim analyses occurred, or whether any estimates were adjusted. These omissions limit the ability to assess analytic choices or reproduce an analysis. They do not establish that a particular analysis was or was not performed outside what is recorded.

10. Multiplicity, Missing Data and Analysis Populations

The registry record lists 27 outcome measures and identifies a range of secondary assessments, including the Alabama Parenting Questionnaire (APQ), Disruptive Behavior Disorders Rating Scale (DBD), Impairment Rating Scale (IRS), Sheehan Disability Scale (SDS), DPICS measures, the Pittsburgh Side Effect Rating Scale, and the Adult ADHD Rating Scale (ADHD RS). It reports 0 analyses. The record does not explain whether this means no results were entered for the listed outcomes or provide an analysis plan for them. Any multiplicity adjustment, hierarchy of outcomes, or distinction between confirmatory and exploratory analyses is not reported in the registry record.

In general, evaluating many outcomes or contrasts can increase the chance of finding at least one apparently unusual result by chance. Methods such as prespecifying a primary contrast or adjusting for multiple comparisons can address this concern, but the record does not state whether any such method was used. The primary outcome description also refers to several categories or time points and indicates that it was not reduced to one comparison, so a single primary estimate is not available for interpretation.

For the primary endpoint, the record says three participants dropped out before completing the assessment and one completed other endpoint measures but not DPICS. The endpoint sample was 23, with 10 in the medication group and 13 in the placebo group. Reasons for missingness, group-specific missingness details beyond those endpoint counts, and any imputation or sensitivity analysis are not reported in the registry record.

In general, missing data can affect both the precision and the interpretation of a group comparison, especially if the likelihood of missingness is related to measured or unmeasured outcomes. The available information is not enough to determine whether that concern applies or to reproduce an analysis using a specific missing-data assumption. The analysis population—such as whether it included all randomized participants or only participants with observed endpoint data—is not reported in the registry record.

11. Safety Results

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

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

Most frequent serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: suicidal ideation (0.0%), self harm attempt (0.0%).

The adverse-event record lists no serious adverse events among the participants at risk in the placebo and treatment arms: each arm reports 0 serious events among 13 participants at risk. The period 1 dose groups also report 0 serious events: 36 participants were at risk in the 30mg group, 21 in the 50mg group, and 17 in the 70mg group. The record separately lists suicidal ideation and self harm attempt at 0.0% as the top serious terms.

For other, non-serious adverse events, the record reports 5 affected participants among 13 at risk in each of the placebo and treatment arms. In the period 1 dose groups, it reports 34 affected among 36 at risk for 30mg, 18 among 21 for 50mg, and 15 among 17 for 70mg. These are counts in different reported groups and periods; the period 1 dose groups should not be added to or directly substituted for the period II arm comparison.

In general, adverse-event counts describe events recorded during the specified reporting period, but they do not by themselves establish whether an event was caused by the study medication. The record does not report deaths; the death entries are not stated. It also does not provide further detail about event severity, duration, or the attribution of non-serious events. The figures should therefore be read as the registry’s reported counts, not as a complete account of comparative safety.

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

The trial addresses a defined research question: whether lisdexamfetamine treatment in adults with ADHD is associated with changes in parenting performance. Its primary endpoint used trained observers’ coding of parent and child behaviors during two structured interactions. The registry record provides information about the trial design, the tasks, and the number of participants with primary endpoint data.

Those details do not establish what the primary comparison found. Group means, standard deviations, an estimated contrast, confidence intervals, and a statistical test are not reported in the registry record. Accordingly, the direction and size of the observed difference, and the precision with which it was estimated, are not available. The stated hypothesis is not a result, and the completed status of the trial does not indicate whether that hypothesis was supported.

Even if a group difference were reported, general interpretation would require attention to the endpoint’s scope. The observations cover defined homework and non-academic tasks, rather than every interaction or setting in family life. The endpoint counts describe coded behavior in those observations; they are not, on their own, a complete measure of parenting or child well-being. The registry record lists several other parenting, impairment, child behavior, and adult ADHD assessments, but does not report their results in the information.

The endpoint sample of 23 also means that outcome data were not available for all 38 enrolled participants. The reasons for the missing DPICS observations and the methods used to account for them are not reported in the registry record. This limits assessment of how representative the endpoint sample was of the enrolled participants and how missing observations might affect a comparison.

Thus, the record supports a description of the question and measurement approach, along with the reported endpoint and safety counts. It does not support a conclusion that lisdexamfetamine improved, worsened, or had no effect on parenting performance. Those outcome claims require results and analysis details that are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically notable because it links a randomized medication comparison with an outcome based on observed parent-child behavior. The endpoint is not simply a rating scale: it involves recorded interactions, trained observers, and counts of behaviors during specified tasks. That measurement approach makes clear why the task context and coding process matter when interpreting the outcome.

The design also has two distinct structures. Medication group is between subjects, while task situation is within subjects because participants completed both interaction types. In general, that combination raises a question about how the analysis represents repeated observations from the same participant and whether the group comparison is intended to average across tasks or describe each task separately. The registry record identifies the structure but does not report the statistical model or the chosen contrast.

The gap between total enrollment of 38 and the primary endpoint sample of 23 is also important for statistical interpretation. A smaller endpoint sample generally provides less information for estimating a group difference than a larger sample would, although the exact precision cannot be determined without outcome variability and an analysis. The record documents the endpoint counts but does not report confidence intervals, group summaries, or a missing-data analysis.

Finally, a question involving parenting performance can be represented by multiple measures and behavior categories. The record lists 27 outcome measures, while reporting 0 analyses and not reducing the primary outcome to one comparison. Without a reported analysis plan or results, readers cannot tell how the different measures and task contexts were prioritized or how multiplicity was addressed. These are statistical interpretation issues, not evidence for or against a treatment effect.

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 interpreting the primary endpoint is that its results are not reported in the registry record. The record gives no group means, standard deviations, effect estimate, confidence interval, or statistical test. As a result, neither the direction nor the precision of the medication-placebo comparison can be assessed.

The endpoint sample was 23, compared with total enrollment of 38. The record attributes the endpoint total to three participants who dropped out before completing the assessment and one participant who completed other endpoint measures but not DPICS. Reasons for these missing observations, their distribution beyond the reported arm sample sizes, and any analysis addressing missing data are not reported in the registry record.

The endpoint description involves two tasks and multiple behavior counts, but it does not report task-specific summaries, the categories analyzed, or how the measurements were combined. The analysis model and any adjustment for repeated observations, covariates, or multiple outcomes are not reported. The record also does not identify the primary analysis population or explain whether the reported group counts correspond to all randomized participants with observed endpoint data.

Randomized and double-masked status describes important aspects of the design, but the record does not report the randomization procedure, allocation concealment, or checks of masking. It also does not report a statistical analysis plan, interim analyses, or a sample-size justification. These limitations constrain reproducibility and interpretation; they do not establish that the trial lacked procedures that are simply not documented in the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Does Pharmacological Treatment of Attention Deficit Hyperactivity Disorder (ADHD) in Adults Enhance Parenting Performance? — NCT01127607.
• Registry record last updated 2014-06-13; status last verified 2014-06.
• Results first posted 2014-06-13.
• 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.

18. Record Summary

The completed phase 4 trial enrolled 38 participants and compared blinded lisdexamfetamine with an identical-appearing placebo in a randomized, double-masked, parallel design. The primary endpoint was DPICS behavior counts from recorded parent-child interactions during a homework task and a non-academic task.

At the end of period II, the primary endpoint included 10 participants in the medication group and 13 in the placebo group. The registry record describes three dropouts before the assessment and one participant without DPICS data despite completing other endpoint measures. It does not report primary endpoint results or the statistical analysis. Safety records report 0 serious adverse events in the two arms and in the period 1 dose groups; non-serious adverse-event counts are also listed by group. The statistical evidence about the primary comparison cannot be determined from the registry record.