Summary of findings 1. n3PUFAs compared to placebo for depression in adults.
| n3PUFAs compared to placebo for depression in adults | ||||||
| Patient or population: Adult patients with major depressive disorder (MDD) Settings: Clinical and community settings Intervention: n3PUFAs Comparison: Placebo | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect (95% CI) | No of Participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Assumed risk | Corresponding risk | |||||
| Placebo | N3PUFAs | |||||
| Depressive symptomology (continuous) HDRS where possible; higher scores indicate greater symptomology Follow‐up: 4 ‐ 16 weeks | The mean depressive symptomology (continuous) in the intervention groups was 0.40 standard deviations lower (0.64 to 0.16 lower). This represents a small to modest difference between groups, equivalent to a HDRS depressive symptomology score of 2.5 (1.0 ‐ 4.0) | 1848 (33 studies) | ⊕⊝⊝⊝ very lowa,b,c,d,e | SMD ‐0.40 (‐0.64 to 0.16) | ||
| Adverse events Study reports Follow‐up: 0 ‐ 16 weeks | Study population | OR 1.27 (0.99 to 1.64) | 1503 (24 studies) | ⊕⊝⊝⊝ very lowc,d,e,f,g | ‐ | |
| 452 per 1000 | 512 per 1000 (450 to 575) | |||||
| Moderate | ||||||
| 250 per 1000 | 297 per 1000 (248 to 353) | |||||
| Depressive symptomology (dichotomous ‐ remission) Depressive symptomology rating scale as used by authors Follow‐up: 4‐16 weeks | Study population | OR 1.13 (0.74 to 1.72) | 609 (8 studies) | ⊕⊕⊝⊝ lowc,d,f,g,h,i | ‐ | |
| 329 per 1000 | 356 per 1000 (266 to 457) | |||||
| Moderate | ||||||
| 174 per 1000 | 192 per 1000 (135 to 266) | |||||
| Depressive symptomology (dichotomous ‐ response) Depressive symptomology rating scale as used by authors Follow‐up: 4‐16 weeks | Study population | OR 1.20 (0.80 to 1.79) | 794 (17 studies) | ⊕⊕⊝⊝ lowc,d,f,g,h,i | ‐ | |
| 445 per 1000 | 490 per 1000 (391 to 589) | |||||
| Moderate | ||||||
| 235 per 1000 | 269 per 1000 (197 to 355) | |||||
| Quality of life Validated quality of life scales as used by authors, CGI (7‐point scale) where possible, higher scores indicate poorer quality of life Follow‐up: 4 ‐ 16 weeks | The mean quality of life in the intervention groups was 0.38 standard deviations lower (0.82 lower to 0.06 higher). This represents a small to modest difference between groups, equivalent to a CGI score of 0.38 (95% CI 0.06 to 0.82) | 476 (12 studies) | ⊕⊝⊝⊝ very lowc,d,f,g,i,j | SMD ‐0.38 (‐0.82 to 0.06) | ||
| Trial non‐completion Study reports Follow‐up: 0 ‐ 16 weeks | Study population | OR 0.92 (0.70 to 1.22) | 1777 (29 studies) | ⊕⊝⊝⊝ very lowc,d,e,f,g | ‐ | |
| 162 per 1000 | 151 per 1000 (119 to 191) | |||||
| Moderate | ||||||
| 200 per 1000 | 187 per 1000 (149 to 234) | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; OR: Odds ratio; SMD: standardised mean difference | ||||||
| GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate. | ||||||
aQuality of the evidence downgraded by one level for study limitations. Judgements of high risk of bias in all studies, and different effects when comparing analyses including only those studies with judgements of low risk of selection bias (allocation concealment), performance bias (blinding of participants and personnel), or attrition bias (incomplete outcome data), and analyses including all studies. bQuality of the evidence downgraded by one level for inconsistency. Evidence of high heterogeneity between studies. Heterogeniety is not well explained by the subgroup analyses. cNo serious concerns regarding indirectness. All evidence used is directly relevant to the research question dQuality of the evidence downgraded by one level for imprecision. Moderate to wide confidence intervals eQuality of the evidence downgraded by one level for publication bias. Strong suspicion of publication bias based on visual inspection of the funnel plot. fQuality of the evidence downgraded by one level for study limitations. Judgements of high risk of bias in all studies included in this analysis gNo serious concerns regarding inconsistency. Limited evidence of heterogeneity between studies hSelected studies only were available to be included in this analysis iFunnel plots were not created for this analysis due to low numbers of studies involved. jQuality of the evidence downgraded by one level for inconsistency. High heterogeneity between studies.