Meta‐analysis of sleep changes in control groups of insomnia treatment trials
Bibliographic record
Abstract
A meta-analysis assessing the magnitude of sleep changes from baseline in placebo-treated (psychological and pharmacological placebo) and untreated groups issued from independent trials was conducted. Comparisons were then performed to assess if the magnitude of sleep changes in the placebo control groups were significantly different than those of the untreated group. Medline, PsychInfo and Current Contents databases (1990-2004) were searched for primary insomnia treatment studies using a randomized controlled parallel-group design. Effect sizes were computed for each end-point variable based on subjective (patient-reported) and polysomnographic measures. Thirty-four studies (n = 1392 subjects) met inclusion criteria; twenty-three used a pharmacological placebo (n = 1163), four used a psychological placebo (n = 81), and seven used a waitlist condition (n = 148). Between-group comparisons were performed using a random effects model analysis. Significant pre-post changes were observed in the pharmacological placebo condition on several sleep parameters, both on objectively and subjectively measured outcomes [objective and subjective sleep onset latency (SOL) and total sleep time (TST) and subjective wake after sleep onset]. Although a tendency was observed for objective SOL, only the changes on subjective SOL and TST in the pharmacological placebo condition were significantly different from the corresponding changes in the untreated group. No differences were significant for the psychological placebo groups. Although the present findings suggest that sleep may significantly change in response to a pharmacological placebo, conclusions remain tentative because of possible confounds that may arise when comparing groups issued from different trials. Further research directly comparing placebo groups and untreated groups from the same randomized trials remains necessary.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.036 | 0.064 |
| Meta-epidemiology (narrow) | 0.004 | 0.002 |
| Meta-epidemiology (broad) | 0.024 | 0.059 |
| Bibliometrics | 0.008 | 0.006 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".