Table 1:

Summary of the evidence of benefits associated with screening for depression through community-based suicide prevention^*

No. of studies	Quality assessment						Summary of findings				GRADE quality of evidence	Importance

							Suicides		Effect

	Design	Risk of bias	Inconsistency	Indirectness	Imprecision	Other considerations	Screening, no. (%)	Control, no. (%)	Relative (95% CI)	Absolute (95% CI)
5 studies19–23^*

Age 65–74 yr	Observational studies	Not serious^†	No serious inconsistency^‡	Very serious^§	No serious imprecision^¶	None^**	n = 35 843 26 (0.07)	n = 61 086 63 (0.1)	RR 0.49 (0.26–0.94)	1 fewer per 1000 (from 0 fewer to 1 fewer)	Very low	Critical

Age 75–84 yr	Observational studies	Not serious^†	No serious inconsistency^‡	Very serious^§	No serious imprecision^¶	None^**	n = 24 441 24 (0.1)	n = 38 644 59 (0.15)	RR 0.44 (0.22–0.88)	1 fewer per 1000 (from 0 fewer to 1 fewer)	Very low	Critical

Age ≥ 85 yr	Observational studies	Not serious^†	No serious inconsistency^‡	Very serious^§	No serious imprecision^¶	None^**	n = 9 769 15 (0.15)	n = 13 594 23 (0.17)	RR 0.56 (0.20–1.53)	1 fewer per 1000 (from 1 fewer to 1 more)	Very low	Critical

Note: CI = confidence interval, GRADE = Grading of Recommendations Assessment, Development and Evaluation, RR = risk ratio.
↵* Our systematic review of benefits associated with screening for depression in adults17 identified 5 quasi-experimental studies with control groups (before–after design with a nonrandomized control group).
↵† The quality-assessment tools identified a few issues with the studies (e.g., selection of non-exposed cohort, blinding and reporting of withdrawals and dropouts); however, the evidence was not downgraded for these reasons.
↵‡ No significant heterogeneity (I² = 0%).
↵§ Directness was downgraded because of concerns regarding characteristics of the study populations. All of the included studies focused on elderly Japanese populations in rural areas, which are unlikely to be representative of Canadians at average or increased risk of depression. Directness was downgraded for the second time because of concerns regarding the nature of the screening programs: the studies reviewed here evaluated the effectiveness of community-based programs of screening for depression, which incorporated screening for depression, follow-up with mental health care or psychiatric treatment, and health education in the community setting. As such, the observed reduction in suicide rates cannot be attributed solely to the screening component of these programs.
↵¶ The number of events is small (< 300, a threshold rule-of-thumb value for dichotomous outcomes); however, given the specific outcome, the evidence was not downgraded.
↵** Insufficient number of included studies (n = 5) to assess publication bias with confidence (≥ 10 papers is the threshold rule-of-thumb value).