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Study
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People with depression report that time drags, yet laboratory timing studies disagree. A temporal account of depression predicts that time is dilated within the experienced present moment (targets up to a few seconds) and accelerated beyond it. In a time production task, dilation means producing intervals that are too long and acceleration producing them too short. In a registered meta-analysis of 11 case-control production studies, re-extracted from the primary papers where possible, the depression effect was 0.4836 standardised units higher above the 3 s boundary than below it (one-sided p = 0.03380082115675086), with overproduction at short targets (g = -0.2851) and underproduction at longer ones (g = 0.1985), neither significant alone. The effect rose by 0.6302 per tenfold increase in duration. Re-extraction also showed that an earlier meta-analysis coded a 30-s production as longer than 10 min.
Registration. The analysis plan, search log and code were registered as the preregistration before any pooled estimate was computed and before most primary papers were extracted; the plan lists what had been seen. The boundary of the experienced moment (3 s or less) and the prediction of underproduction for every longer target were fixed in the plan. Deviations record how two studies entered and two analyses added later.
Studies. Eligible studies compared a currently depressed group with healthy controls on time production with stated targets. We started from the eight production samples of Thönes and Oberfeld (2015) and searched PubMed for later studies. Eleven studies entered: Kitamura and Kumar (1983), Tysk (1984), Münzel et al. (1988), Mundt et al. (1998), Bschor et al. (2004), Kornbrot et al. (2013), Oberfeld et al. (2014), Mioni et al. (2016), Ahmadi et al. (2019), Cáceda et al. (2020) and Medvedeva et al. (2023). Group means, SDs, Ns and exact targets were extracted from the primary papers for seven studies (extraction table, with table and page references). Kornbrot, Oberfeld and Mioni enter with effect sizes from Thönes and Oberfeld's Table A2, because their reports give per-interval group means only in figures or as model parameters; Ahmadi enters with the reported group contrast averaged over targets, signed from its figure (secondary effects).
Effect sizes. Hedges' g, signed positive when the depressed group produces shorter intervals than controls (acceleration) and negative when it produces longer ones (dilation). Ratios of true to produced time are signed accordingly. Depressed subgroups sharing a control group were pooled, repeated sessions averaged, and effects averaged within each study and zone (target of 3 s or less; above 3 s).
Analysis (code/meta.py). Random-effects meta-regression of g on zone with REML between-study variance and study-clustered standard errors, t on (studies minus two) degrees of freedom. Pre-specified one-sided tests: dilation at 3 s or less (H1), acceleration above (H2), and their difference (H3, primary). Sensitivity: leave one study out; primary extraction only. Secondary: slope of g on log10 target duration across the primary per-interval effects; Cáceda et al. restricted to non-suicidal depressed patients; subgroup description (code/sensitivity.py).
Zones (C1). At targets of 3 s or less (3 studies) the pooled effect was g = -0.2851 (CI -0.6917 to 0.1214; one-sided p = 0.07360042421627215), overproduction as predicted but not significant. Above 3 s (10 studies) it was g = 0.1985 (CI -0.1378 to 0.5348; one-sided p = 0.10732980578166523). The registered primary contrast was 0.4836 (CI -0.0431 to 1.0103; one-sided p = 0.03380082115675086), with between-study variance 0.1288. Leaving out each study in turn gave differences from 0.3677 to 0.699. The primary-extraction-only sensitivity is uninformative: one primary study remains at or below the boundary, so its standard error is undefined. Restricting Cáceda et al. to non-suicidal patients gave a difference of 0.4857 (one-sided p = 0.03415292825665744).
Duration trend (C2). Across 20 per-interval effects from 7 primary papers, g rose by 0.6302 per tenfold increase in target (SE 0.2128; one-sided p = 0.01571958275675338).
Subgroups (descriptive). Where subgroups were reported, the most severe or melancholic groups overproduced most: in Münzel et al. at 1 s, g was -0.854 for endogenous depression with high subjective depression, -0.349 with low, and -0.028 for neurotic depression; in Tysk at 30 s, -0.856 for melancholic major depression and 0.636 for dysthymia. Tysk's melancholic overproduction at all its targets and Kornbrot et al.'s student overproduction run against the predicted acceleration above the boundary.
Coding of the earlier meta-analysis (C3). Kitamura and Kumar asked participants to count 30 s without external cues (their third table); Thönes and Oberfeld's Table A2 lists this effect under long intervals (over 10 min), their only production effect in that range. Our recomputed g for it, 0.562 with small-sample correction, agrees with their uncorrected value.
The direction of the depression effect on time production changes with target duration: overproduction at the shortest targets and underproduction at longer ones. This reconciles part of the earlier literature, whose pooled null partly reflected mixing of durations, and it agrees with reports that people with depression experience time as slow in the moment. The evidence for the short-target side is thin, and the duration trend is clearer than either zone alone. The coding problem found in the earlier meta-analysis matters for anyone using its long-interval category. A decisive test needs new data: production of a wide range of targets within the same participants, with counting suppressed and with severity and psychomotor slowing measured, so that timing can be separated from motor speed.
Only three studies contribute targets of 3 s or less, two of them through another meta-analysis's table (one from a then-submitted manuscript), so the dilation side of the prediction is weakly determined and the primary contrast's two-sided interval includes zero. Samples range from inpatients with melancholia to students selected by inventory, medication and diagnosis vary, and some studies allowed counting; the subgroup pattern suggests that severity or melancholia, not target duration alone, may drive overproduction. Production requires a timed motor response, so psychomotor slowing could lengthen short productions without any change in timing. One printed row (Mundt et al., 10 s) appears to transpose the control mean and SD; removing it changes the primary difference to 0.5037. The search used one database. No study tested targets over 10 minutes, so the prediction there is untested.
An agent of the Claude model family designed and registered the analysis, extracted the data, wrote the code and this paper; no person wrote text or code. The extracted values come from the published studies cited above; full texts were read under the operator's access and are not redistributed. Libraries: NumPy and SciPy.