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 Effects of a New Behavioral Intervention on Alcohol Craving and Drinking (NCT02831049), a randomized na study. The primary outcome is Change in Self-reported Alcohol Craving in the Laboratory Sessions.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT02831049 |
| Phase | NA |
| Condition | Alcohol Drinking, Alcohol Drinking Related Problems |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 23 |
| Arms in the primary outcome | n/a |
| Lead sponsor | National Institute on Drug Abuse (NIDA) |
| Results posted | Yes |
2. Clinical Question
Population
Healthy people ages 21 to 65 who were mildly concerned about their drinking and met the registry’s recent drinking thresholds were eligible. The primary outcome population is described as all participants who completed the study.
Intervention
The experimental procedure paired alcohol-cue retrieval with alcohol-cue extinction, abbreviated A/A in the registry. Participants drank an alcoholic beverage individualized to produce a 0.06 g/dL blood alcohol content, then encountered alcohol-associated cues without further drinking.
Comparator
Two control procedures were described: soft-drink retrieval followed by alcohol extinction (S/A), and alcohol retrieval followed by soft-drink extinction (A/S). Each used a different combination of retrieval and extinction cues.
Primary question
How did self-reported craving change after cues during the laboratory sessions, and how did craving change around renewal and reinstatement tests after the retrieval-extinction sessions? Numerical comparisons between groups are not reported in the registry record.
The study addressed whether visual imagery and behavioral techniques could alter alcohol craving and drinking. Its specific primary endpoint was not a direct measure of drinking: it was the estimated mean change in cue-elicited craving scores, expressed as scores after cues minus scores before cues. The registry also lists a secondary outcome, change in alcohol craving assessed with the Penn Alcohol Craving Scale.
Eligibility criteria focused on people with recent drinking above the registry’s stated thresholds: for women, more than three drinks on any single day or more than seven drinks per week; for men, more than four drinks on any single day or more than 14 drinks per week. These criteria describe the intended study population, not all people who drink alcohol. The registry record does not report numerical primary endpoint results, so the direction and size of any group differences cannot be evaluated from the posted information.
3. Trial Design
The registry describes NCT02831049 as a randomized, single-masked, parallel-group study with enrollment of 23. It is marked completed. The study start date is 2017-05-05, and the primary completion date is 2020-04-21. The phase is listed as not applicable. The sponsor is the National Institute on Drug Abuse (NIDA).
Three behavioral groups were described. In A/A, alcohol-associated cues were used for retrieval and extinction. In S/A, soft-drink cues were used for retrieval and alcohol-related cues for extinction. In A/S, alcohol was used for retrieval and soft-drink cues for extinction. The registry descriptions say participants completed four sessions involving retrieval and extinction portions. Detailed session procedures beyond those descriptions are not reported in the registry record.
The study summary describes six visits over approximately four weeks. Participants were to carry a smartphone and make daily reports about drinking, moods, and activities; the phone’s GPS was to record locations. Visits included screening procedures, urine and breath samples, and exposure to cues. The summary also describes avoiding alcohol and illicit or over-the-counter drugs for at least 24 hours before each visit. These are descriptions of the study procedures, not numerical evidence about the intervention’s effects.
The registry does not report how the random sequence was generated, how allocation was concealed, or which people were masked. It also does not report a formal sample-size justification or the detailed statistical analysis plan. The observed enrollment should therefore not be treated as evidence that the study was sized to detect a particular effect. Arm-specific primary outcome sample sizes 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
| Stage | Experimental Group: Alcohol Retrieval / Alcohol Extinction (A/A) | Control Group A: Soft-drink Retrieval / Alcohol Extinction (S/A) | Control Group B: Alcohol Retrieval / Soft-drink Extinction (A/S) |
|---|---|---|---|
| STARTED | 7 | 8 | 8 |
| COMPLETED | 6 | 7 | 6 |
| NOT COMPLETED | 1 | 1 | 2 |
Reasons for not completing this period:
| Reason | Experimental Group: Alcohol Retrieval / Alcohol Extinction (A/A) | Control Group A: Soft-drink Retrieval / Alcohol Extinction (S/A) | Control Group B: Alcohol Retrieval / Soft-drink Extinction (A/S) |
|---|---|---|---|
| Lost to Follow-up | 0 | 0 | 1 |
| Withdrawal by Subject | 0 | 1 | 1 |
| Pandemic shutdown | 1 | 0 | 0 |
Analysis population for the primary outcome, as defined in the registry: All participants who completed the 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.
| Characteristic | Unit | Experimental Group: Alcohol Retrieval / Alcohol Extinction (A/A) | Control Group A: Soft-drink Retrieval / Alcohol Extinction (S/A) | Control Group B: Alcohol Retrieval / Soft-drink Extinction (A/S) | Total |
|---|---|---|---|---|---|
| Participants analysed | 7 | 8 | 8 | 23 | |
| Age, Categorical: <=18 years | Participants | 0 | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Participants | 7 | 8 | 8 | 23 |
| Age, Categorical: >=65 years | Participants | 0 | 0 | 0 | 0 |
| Sex: Female, Male: Female | Participants | 3 | 3 | 3 | 9 |
| Sex: Female, Male: Male | Participants | 4 | 5 | 5 | 14 |
| Ethnicity (NIH/OMB): Hispanic or Latino | Participants | 1 | 0 | 1 | 2 |
| Ethnicity (NIH/OMB): Not Hispanic or Latino | Participants | 6 | 8 | 7 | 21 |
| Ethnicity (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): American Indian or Alaska Native | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Asian | Participants | 1 | 0 | 0 | 1 |
| Race (NIH/OMB): Native Hawaiian or Other Pacific Islander | Participants | 0 | 0 | 0 | 0 |
| Race (NIH/OMB): Black or African American | Participants | 0 | 4 | 4 | 8 |
| Race (NIH/OMB): White | Participants | 6 | 2 | 4 | 12 |
| Race (NIH/OMB): More than one race | Participants | 0 | 2 | 0 | 2 |
| Race (NIH/OMB): Unknown or Not Reported | Participants | 0 | 0 | 0 | 0 |
| Region of Enrollment: United States | participants | 7 | 8 | 8 | 23 |
6. Primary Endpoint
The registry lists the primary outcome as Change in Self-reported Alcohol Craving in the Laboratory Sessions, measured over Up to 75 minutes during trial sessions.
| Element | Registry entry |
|---|---|
| Result type | Mean |
| Measure of spread | 95% Confidence Interval |
| Unit | units on a scale |
| Endpoint classification | Continuous Endpoint |
The primary endpoint was change in self-reported alcohol craving in laboratory sessions. Participants encountered alcohol cues and an alcohol-containing beverage, then rated their desire for a drink on a visual analogue scale from 0, meaning no desire for a drink, to 100, meaning a strong desire for a drink. Higher scores indicate more craving. The endpoint is expressed as the estimated mean change in scores after cues minus scores before cues.
The registry describes four retrieval-extinction intervention sessions followed by a test session. Renewal was assessed by comparing an extinction context with a novel challenge context, and reinstatement was assessed after a priming dose of alcohol. In the final session, the outcome involved changes in craving before versus after renewal and again after reinstatement. The timeframe is stated as up to 75 minutes during trial sessions.
Craving ratings are used to quantify a participant’s reported response to cues in a structured setting. General statistical context: a change score can describe how a measure shifts within a participant across specified conditions, while group comparisons can assess whether those changes differ between assigned procedures. The registry record does not report the estimated changes, uncertainty intervals, or numerical between-group comparisons for this endpoint. It therefore does not establish from the posted results how large or precise any observed change was.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The record establishes the trial’s design and defines the primary outcome, but it does not provide numerical primary outcome estimates. Although the outcome description specifies mean changes in craving scores, no group-specific means, mean changes, confidence intervals, or p-values are reported in the registry record. Consequently, the direction, size, and precision of a treatment contrast cannot be described from the posted results.
The endpoint has several components: craving was assessed in laboratory sessions and in a final session involving renewal and reinstatement tests. The registry notes that the primary outcome has several categories or time points and was not reduced to one comparison. This matters because a single summary contrast would not necessarily represent every component of the outcome. Without estimates for the separate comparisons, it is not possible to tell whether they were similar or differed in direction or magnitude.
The registry lists 23 participants enrolled and describes three randomized groups. The adverse-event record gives group-specific numbers at risk, but those figures are not the same as primary endpoint analysis sample sizes. The primary outcome population is described as all participants who completed the study; the number who completed and the number contributing data at each primary endpoint assessment are not reported in the registry record.
No statistical model, adjustment procedure, or inferential result is listed among the registry analyses; the analysis count is 0. The record does not report whether the outcome was adjusted for baseline craving, repeated measurements, or other variables. No effect estimate can be independently checked or recalculated from the information available. General statistical context: an estimate describes the magnitude and direction of a contrast, while a confidence interval expresses the uncertainty associated with that estimate under the analysis assumptions. Neither can be assessed because endpoint estimates and intervals are not reported.
The registry includes planning assumptions for illustrative sample-size calculations based on fractions of an observed effect, equal allocation between two arms, a two-sided significance level of 0.05, and a normal approximation. No resulting participant counts are reported in the record. Such calculations, when displayed, are planning illustrations rather than evidence of the trial’s observed power or a substitute for the missing outcome estimates. The posted information supports a description of what was studied, but not a conclusion about the comparative effects of the procedures.
9. Statistical Methods Explained
What does randomization contribute?
General statistical context: randomization assigns participants to study groups using a chance-based process. When implemented well, it can reduce systematic differences between groups at the start of a study, on average. It does not guarantee that groups are identical, particularly in a small study. This registry identifies the study as randomized, but the sequence-generation and allocation-concealment methods are not reported in the registry record. The assignment process therefore cannot be evaluated in detail.
What does the parallel-group design mean?
General statistical context: in a parallel-group design, participants are assigned to one group and receive that group’s procedure rather than crossing through every procedure. The registry lists three behavioral groups: A/A, S/A, and A/S. The labels describe different combinations of retrieval and extinction cues. The specific planned pairwise comparisons and the primary comparison of interest are not reported in the registry record. A three-group design can support multiple contrasts, but the registry does not identify which contrast, if any, was designated as the principal inferential comparison.
How should a mean change be understood?
The primary outcome is a mean change in craving scores, calculated as scores after cues minus scores before cues. General statistical context: a mean summarizes the central level of a continuous measure, and a mean change summarizes average movement between paired measurements. A positive or negative change would have a direction under this definition, but the registry does not report numerical changes, so no direction can be assigned to the study result. The study’s measure ranges from 0 to 100, with higher scores indicating more craving.
What would a confidence interval add?
General statistical context: a confidence interval gives a range of values compatible with an estimate under a specified statistical method and its assumptions. Its width reflects precision; a narrower interval generally indicates greater precision than a wider one. The primary outcome identifies a 95% confidence interval as its dispersion measure, but no interval values are reported in the registry record. Without those values, the precision of the estimated mean changes cannot be assessed. An interval is not a guarantee that the true value lies within its endpoints, and it does not by itself establish whether a difference matters clinically.
Why do repeated measures and multiple comparisons matter?
The primary outcome involves cue responses during intervention sessions and a final session with renewal and reinstatement tests. General statistical context: measurements from the same participant are often related rather than independent. An analysis of repeated measurements may need to account for that correlation. The model used to handle repeated measurements is not reported in the registry record. The registry also flags several categories or time points rather than one reduced comparison. When multiple outcomes or contrasts are examined, the chance of at least one apparently unusual result can increase. Whether any multiplicity adjustment was planned or used is not reported in the registry record.
What can planning calculations tell us?
The registry describes sample-size assumptions for a planning illustration: two-sided significance level 0.05, equal allocation between two arms, a normal approximation, and an effect defined as a stated fraction of the observed effect. No resulting sample-size values are reported in the registry record. General statistical context: a planning calculation estimates how many participants might be needed under assumptions about the target effect and variability. It is not an observed effect, and it is not observed power. The trial’s own sample-size justification and the assumptions used to design the study are not reported in the registry record.
What analysis information is unavailable?
The registry lists 0 analyses. It does not report the statistical model, a test statistic, a p-value, covariate adjustments, a missing-data method, or a method for handling protocol deviations. The outcome population is described as all participants who completed the study, but the number of completers and endpoint-specific analysis counts are not reported. These omissions mean that the analytical choices and their consequences cannot be reproduced or assessed from the registry record.
10. Multiplicity, Missing Data and Analysis Populations
Multiplicity is relevant because the primary outcome is described across several categories or time points, including intervention-session craving and assessments around renewal and reinstatement. The registry indicates that the primary outcome was not reduced to one comparison. It does not report which comparisons were planned as primary for inference, whether additional comparisons were exploratory, or whether a multiplicity adjustment was used. The six outcome measures listed in the registry do not come with a detailed analysis hierarchy in the posted record.
Missing-data procedures are not reported in the registry record. The primary outcome population is described as all participants who completed the study, but the number of completers, withdrawals, and participants with observed data at each assessment are not stated. The record does not explain how missing ratings, incomplete sessions, or other unavailable measurements were handled. It also does not report whether any sensitivity analyses examined the effect of missing data.
The registry describes a randomized trial, but it does not report whether the primary analysis followed an intention-to-treat approach, a per-protocol approach, or another analysis population. The listed primary population of study completers does not establish which assigned participants were included in each endpoint analysis. These details are important because analysis populations and missing-data assumptions can affect estimates and uncertainty. Without them, the numerical analysis cannot be reproduced or fully interpreted.
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 |
|---|---|---|---|
| Experimental Group: Alcohol Retrieval / Alcohol Extinction (A/A) | 0 | 7 | 0.0% |
| Control Group A: Soft-drink Retrieval / Alcohol Extinction (S/A) | 0 | 8 | 0.0% |
| Control Group B: Alcohol Retrieval / Soft-drink Extinction (A/S) | 0 | 8 | 0.0% |
Deaths
| Arm | Deaths (participants affected of at risk) |
|---|---|
| Experimental Group: Alcohol Retrieval / Alcohol Extinction (A/A) | 0 of 7 |
| Control Group A: Soft-drink Retrieval / Alcohol Extinction (S/A) | 0 of 8 |
| Control Group B: Alcohol Retrieval / Soft-drink Extinction (A/S) | 0 of 8 |
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 |
|---|---|
| Experimental Group: Alcohol Retrieval / Alcohol Extinction (A/A) | 1 of 7 |
| Control Group A: Soft-drink Retrieval / Alcohol Extinction (S/A) | 1 of 8 |
| Control Group B: Alcohol Retrieval / Soft-drink Extinction (A/S) | 0 of 8 |
Most frequent non-serious adverse event terms
| Event term | Organ system | Experimental Group: Alcohol Retrieval / Alcohol Extinction (A/A) | Control Group A: Soft-drink Retrieval / Alcohol Extinction (S/A) | Control Group B: Alcohol Retrieval / Soft-drink Extinction (A/S) |
|---|---|---|---|---|
| Diarrhoea | Gastrointestinal disorders | 0 of 7 | 1 of 8 | 0 of 8 |
| Menstrual discomfort | Reproductive system and breast disorders | 1 of 7 | 0 of 8 | 0 of 8 |
The registry reports serious adverse events by group. There were 0 serious adverse events among 7 participants at risk in A/A, 0 among 8 at risk in S/A, and 0 among 8 at risk in A/S. Deaths are listed as 0 in each group. These are the recorded counts; they do not describe the primary craving outcome.
The record also lists other adverse events: 1 among 7 participants at risk in A/A, 1 among 8 at risk in S/A, and 0 among 8 at risk in A/S. The types of these other events are not reported in the registry record. No serious adverse event terms are listed.
General statistical context: event counts describe what was recorded within the stated at-risk groups. With small groups and few events, the counts alone provide limited precision for comparing event occurrence between groups. Zero recorded serious events does not establish that an event is impossible or that the groups have identical safety profiles. The registry does not provide further detail about event definitions, severity grading for other events, timing, or how investigators judged relatedness. These figures should therefore be read as the posted counts, not as a complete comparative safety analysis.
12. What the Result Does, and Does Not, Mean
The registry record describes a randomized behavioral study with three combinations of alcohol-related and soft-drink cues. Its central laboratory outcome was change in self-reported craving, with additional testing around renewal and reinstatement. The record therefore identifies a specific experimental question and a defined measurement approach. It does not provide the numerical endpoint results needed to determine the size, direction, or precision of the observed changes.
The posted information does not establish whether one group had more or less craving than another, whether any contrast was statistically distinguishable from zero, or whether the results were consistent across the different assessment times. Those conclusions require estimates and an account of the analysis. Neither is reported in the registry record. A study objective is not itself evidence that an intervention changed craving or drinking.
The primary outcome measures reported craving in laboratory circumstances. It is not the same as a direct measure of drinking behavior in everyday life. The study summary describes smartphone reports of drinking, moods, and activities, and the registry lists a secondary craving measure using the Penn Alcohol Craving Scale. Numerical results for those outcomes are not reported in the registry record. The laboratory endpoint alone would not establish what happened to drinking outside the study sessions.
General statistical context: a study result is most informative when its estimate is considered alongside uncertainty, the analysis population, and the design. Here, the primary endpoint estimate, confidence interval, p-value, analysis sample size, and detailed model are not reported. The enrollment of 23 and the recorded adverse-event counts do not fill those gaps. The information available supports a description of the question and procedures, but it does not support a conclusion about efficacy, comparative benefit, or the practical importance of any effect.
13. Why This Trial Matters Statistically
This trial is statistically interesting because the behavioral procedures differ in the pairing of retrieval and extinction cues. The three groups allow the study question to distinguish among alcohol retrieval followed by alcohol extinction, soft-drink retrieval followed by alcohol extinction, and alcohol retrieval followed by soft-drink extinction. That structure makes the definition of the target comparison important. The registry record does not identify a single primary contrast among these groups.
The primary outcome also involves more than one assessment context. Craving was measured in laboratory sessions, and the final session included tests of renewal and reinstatement. Those contexts may address different parts of the proposed behavioral process, so reducing them to a single comparison could conceal variation across assessments. The registry explicitly notes multiple categories or time points, but numerical results for those components are not reported.
The record illustrates a distinction between a clearly described endpoint and an interpretable result. The craving scale, direction of scoring, and change-score definition are specified. Yet without estimates, confidence intervals, analysis details, and endpoint-specific sample sizes, readers cannot judge magnitude or precision. This is especially consequential in a study with enrollment of 23 and three groups, where estimates may be uncertain; the actual uncertainty cannot be quantified from the posted information.
Finally, the registry’s planning assumptions should be kept separate from observed evidence. They describe an illustrative calculation framework, not a demonstrated ability to detect a particular effect. A transparent account of the planned comparisons, missing-data handling, and complete outcome estimates would be needed to connect the design to the statistical conclusions. The posted record allows readers to identify those interpretive requirements, but not to resolve them.
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 numerical primary outcome results are not reported in the registry record. There are no group-specific craving changes, confidence intervals, or inferential statistics. The registry lists 0 analyses and notes that the primary outcome spans several categories or time points rather than one comparison. As a result, neither a primary contrast nor the component results can be assessed.
The registry does not report the number of participants who completed the study or the number with usable data at each endpoint assessment. It identifies all study completers as the primary outcome population, but does not provide endpoint-specific analysis counts or explain how missing observations were handled. The specific randomization and masking procedures are also not reported, limiting assessment of implementation.
Some procedural descriptions are brief. Although the groups and broad cue combinations are identified, more detailed information about the behavioral procedure and the exact statistical model is not reported in the registry record. The record also does not explain how the multiple assessments were prioritized or whether multiplicity was addressed. This limits reproducibility and makes it difficult to determine how the reported outcome was intended to be analyzed.
The eligibility criteria describe a selected population of healthy people ages 21 to 65 who were mildly concerned about their drinking and met specified recent drinking thresholds. Results, if available, would therefore apply most directly to people fitting those criteria and participating in the described laboratory procedures. In this record, results are not available for assessing even that population-specific effect. The absence of numerical estimates prevents assessment of both statistical precision and practical relevance.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Effects of a New Behavioral Intervention on Alcohol Craving and Drinking — NCT02831049.
- Registry record last updated 2025-01-16; status last verified 2024-10-09.
- Results first posted 2025-01-16.
- 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
NCT02831049 is a completed randomized, single-masked, parallel-group behavioral study sponsored by the National Institute on Drug Abuse (NIDA). Enrollment was 23. The study compared three retrieval-extinction cue procedures involving alcohol-related and soft-drink cues. The registry describes six visits over approximately four weeks and four retrieval-extinction sessions.
The primary endpoint was mean change in laboratory self-reported alcohol craving after cues minus before cues, with renewal and reinstatement assessments in the final session. The primary outcome population is described as all participants who completed the study. A secondary outcome was change in alcohol craving assessed using the Penn Alcohol Craving Scale.
The registry does not report numerical primary outcome results, a statistical model, missing-data handling, or a detailed analysis plan. It lists 0 analyses and indicates that the primary outcome includes multiple categories or time points. Serious adverse events and deaths were recorded as 0 in each group; other adverse events were recorded as 1, 1, and 0 across A/A, S/A, and A/S, respectively. These counts do not substitute for the missing efficacy estimates.