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Screening for depression: a systematic review and meta-analysis
Homa Keshavarz PhD, Donna Fitzpatrick-Lewis MSW, David L. Streiner PhD,
Maureen Rice MLIS, Usman Ali MD MS, Harry S. Shannon PhD, Parminder Raina PhD
Abstract
Background: The Canadian Task Force on Preventive Health Care has a guideline on screening for depression among adults 18 years
of age or older at average or high risk for depression. To provide evidence for an update of this guideline, we evaluated the literature on
the effectiveness of screening for depression in adults.
Methods: For the period 1994 to May 23, 2012, we searched the following electronic databases: MEDLINE, Embase, PsycINFO, the
Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews. Randomized controlled trials,
observational studies and systematic reviews with evidence for the benefits or harms of screening for depression were eligible for
inclusion. We performed screening for relevance, extraction of data, analysis of risk of bias and quality assessments in duplicate. We
used the generic inverse variance method to conduct a meta-analysis. To determine confidence in the effect, we analyzed the results
according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system.
Results: Five quasi-experimental studies (before–after design with a nonrandomized control group) met the inclusion criteria for this
review. These studies reported on the effect of community-based screening for depression, with follow-up on the risk of suicide completion, for older residents in regions of rural Japan with high suicide rates. Meta-analysis showed that the screening program had a protective effect on the overall incidence of suicide completion (ratio of rate ratios [RRR] 0.50, 95% confidence interval [CI], 0.32–0.78).
When sex was considered, the RRR indicated a significantly lower rate of suicide among women (RRR 0.37, 95% CI 0.21–0.66) but not
among men (RRR 0.67, 95% CI 0.35–1.27). The overall GRADE rating applied to this evidence indicated very low quality. No studies
addressing the harms of screening for depression met the inclusion criteria for the review.
Interpretation: There is very limited research evidence allowing conclusions about the effectiveness of screening for depression in
either average-risk or high-risk populations.
D
epression is a complex mental illness that is associated with disability and reduced quality of life for
the person with the disorder; it also poses a substantial societal burden. The prevalence of past-year
episodes of depression in the Canadian population has been
estimated to vary from 5% to 8.2% annually.1,2 In 2005, the
Canadian Task Force on Preventive Health Care published a
guideline on screening for depression among adults (18
years or older) at average or high risk for depression.3 In
2013, the task force released an updated guideline.4 The systematic review on which this paper is based provided evidence for that 2013 update.
The World Health Organization (WHO) Psychological
Problems in General Health Care study,5 released in 1996,
reported that primary care physicians diagnosed major depression in only 42% of adult patients who had the condition. The
potential beneits of screening for depression in adults include
improved detection of major depressive disorder, dysthymia and
subsyndromal depression. Improvements in detection can lead
to earlier treatment, and treatment of major depressive disorder
in adults is thought to result in improved outcomes, such as
better quality of life, better work life and minimization of the
© 2013 Canadian Medical Association or its licensors
risk of suicide.6 One argument against screening is that screening instruments have low positive predictive value, meaning
that many people with a positive screening result do not have
depression.7,8 Although a previous review found no literature
speciically evaluating the harms associated with screening for
depression and related disorders,9 those with positive screening
results who do not have the disorder may be exposed to stigmatization and further psychologic testing, as well as unnecessary
psychologic and pharmacologic treatment regimes.
In preparing to update the guideline, the Canadian Task
Force on Preventive Health Care undertook a de novo review,
given the guideline’s focus on a comparison between screening
for depression in people with no apparent symptoms versus no
Competing interests: None declared.
This article has been peer reviewed.
Correspondence to: Parminder Raina, praina@mcmaster.ca, or Donna
Fitzpatrick-Lewis, fitzd@mcmaster.ca
CMAJ Open 2013. DOI:10.9778/cmajo.20130030
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screening. Our review thus differed from the reviews by
Pignone and colleagues10 and O’Connor and colleagues,9 which
served as the evidentiary base for the 2009 US Preventive Services Task Force screening recommendations for adults. Those
reviews included studies in which all members of the population were screened, the comparisons being treatment versus no
treatment or feedback (providing depression score to the
patient or physician) versus no feedback. The review by
Gilbody and colleagues11 was also outside the scope of our
review, because it was a review of depression screening tools.
In the current systematic review, we explored the beneits
and harms of screening for depression in asymptomatic adults
18 years of age or older from the general population (at average risk for depression) and in adults at high risk for depression in both primary care and other outpatient settings.
Methods
The search strategy was developed by a librarian (M.R.) experienced in searches for systematic reviews. We searched several electronic databases, speciically MEDLINE, Embase,
PsycINFO, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews, for the
period 1994 to May 23, 2012. The MEDLINE search was
updated in April 2013, 6 weeks before publication of the
guideline, to identify any recent, potentially relevant randomized controlled trials. The search was broad, the only limitations being date of publication, research subjects (limited to
humans) and language (English or French) (see Appendix 1 at
www.cmajopen.ca/content/1/4/E159/suppl/DC1). In addition, we searched the grey literature (primarily Canadian
sources) up to May 2012, using a number of keyword terms
for depression and screening.
Eligible studies were those involving adults at least 18
years of age from unselected populations or high-risk groups
(see Appendix 2 at www.cmajopen.ca/content/1/4/E159/suppl
/DC1). The intervention of interest was routine screening,
and we considered studies of any design that compared
screening with no screening. The study settings were primary
care or, for high-risk groups, specialty clinics. The outcomes
of interest were quality of life, rates of suicidality (attempts or
ideation), all-cause mortality, depression-related mortality,
rates of hospital admission and changes in symptoms of
depression (treatment response or remission). The harms of
interest were psychological stress (labelling, anxiety or stigma),
false positive results, false negative results, decreased day-today functioning and increase in symptoms (see Appendix 3 at
www.cmajopen.ca/content/1/4/E159/suppl/DC1).
To determine factors indicating possible higher risk of
depression, we searched the websites of reputable sources of
information about depression, including the Mayo Clinic
(Rochester, Minn.), the Canadian Mental Health Association,
the Centre for Addiction and Mental Health (Toronto, Ont.),
the Mood Disorders Society of Canada and one published
source.12 From these sources, we collated a list of risk factors
(see Appendix 2), which we used to identify studies involving
high-risk populations.
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Study selection and data extraction
Pairs of reviewers experienced in systematic review methodology and statistics (PhD researchers [including H.K.], a PhD
student and a research assistant; pairings varied) independently
screened all identiied citations for relevance, inclusion criteria
and study quality and performed the data extraction. Potentially
relevant citations went through 2 levels of title and abstract
screening. The irst screening was broad, to eliminate citations
that were obviously not on topic; the second screening had
more speciic exclusion criteria, such as age less than 18 years
and study not representing primary research on screening. Any
citation deemed potentially relevant was retrieved for full
review. Pairs of reviewers (as described above) independently
reviewed the potentially relevant studies, and for any studies
excluded at this stage, agreement about the reason for exclusion
was required. All disagreements were resolved through discussions.13 Reference lists of on-topic systematic reviews retained
for analysis were searched to ensure that we considered all primary studies meeting our inclusion criteria.
Quality assessment
We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to determine the quality of the evidence. This widely used system has been endorsed
by over 40 major organizations, including the WHO, the US
Centers for Disease Control and Prevention, and the US Agency
for Healthcare Research and Quality.14 GRADE considers 5 criteria (design, consistency, directness, precision and reporting bias)
to rate the quality of evidence as high, moderate, low or very low;
these ratings represent an assessment of the likelihood that further research will lead to changes in the estimate of effect.15 We
assessed the risk of bias with the Newcastle–Ottawa tool.16 Two of
the authors (H.K. and D.F.L.) independently assessed the evidence according to these criteria and reached agreement on the
ratings and the overall quality of the summary statistics.
Statistical analysis
In the included studies, data were obtained before (baseline) and
after implementation of the intervention or control measure.
Two of the 5 identiied papers17,18 included 2 control groups; the
remaining 3 studies each had 1 control group.19-21 Four out of the
5 papers presented data using adjusted incidence rate ratios (IRR)
and one reported adjusted odds ratios. This variation in data presentation necessitated calculation of the ratio of rate ratios (RRR)
for each group (i.e., ratio of postimplementation rate to preimplementation rate in the geographic area where the intervention
was applied divided by the corresponding ratio of postimplementation rate to preimplementation rate in the control area). We
used Cochrane Review Manager software (RevMan, version 5.1,
Nordic Cochrane Centre of the Cochrane Collaboration,
Copenhagen, Denmark) to conduct the meta-analysis.
We calculated a weighted intervention effect across studies
using data for overall population and data stratiied by age and
sex. An RRR of less than 1.0 indicates a reduction in the outcome IRR. We calculated standard errors for logarithms of rate
ratios and 95% conidence intervals (CIs) for the RRR values,
assuming that the number of events in each study area in each
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period followed a Poisson distribution. We used the generic
inverse variance method with a random-effects meta-analysis
model, because all of the included studies had been done by
the same team of authors working with the same research
design. We used the Cochrane Q (α = 0.10) and the I2 statistic
to quantify statistical heterogeneity among studies, where p <
0.10 indicated a high level of statistical heterogenity.13
titles and abstracts. We retrieved a total of 1532 papers and
assessed them against the inclusion criteria; 1527 of these
papers were excluded. Five quasi-experimental studies
(before–after design with a nonrandomized control group), all
with the same irst author, met the inclusion criteria and provided the evidence for the review questions (Table 1).17–21
Average-risk populations
Results
Study selection and characteristics
Our search identiied 14 226 potentially relevant citations
(Figure 1). Of these, 12 694 were excluded after screening of
The irst question of interest for this review was, “What is the
evidence for the beneit (i.e., improvement in clinical outcomes) of screening for depression in asymptomatic adults (18
years of age or older) from the general population, in either
primary care or other outpatient settings?” No studies of
Articles identified by database
search with level 1 title and
abstract screening
n = 14 226
Excluded n = 11 563
(nonhuman studies, studies not about
depression, letters, commentaries,
editorials, language other than English or
French)
Articles with level 2 title
and abstract screening
n = 2663
Excluded n = 1131
(not an adult population, not a primary study,
focused on treatment, mental health issue
other than major depressive disorder)
Articles with full-text
screening
n = 1532
Excluded n = 1527
• Not about screening program n = 787
• Not an eligible study design n = 273
• Not an eligible population n = 248
• No comparator n = 144
• Not an eligible setting n = 37
• Only about harms of treatment n = 37
• Modelling study n = 1
Studies included
n=5
General population
(effectiveness
of screening)
n=0
Older population
(effectiveness
of screening)
n=5
High-risk population
n=0
Harms of screening
n=0
Figure 1: Identification and evaluation of studies for a systematic review of screening for depression.
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screening for depression in the average-risk population as a
whole met the inclusion criteria of this review. The 5 included
studies focused on community-based screening for depression
among older people (i.e., age ≥ 60 or age ≥ 65, depending on
the study).17–21 These studies were conducted in rural regions
of Japan, where suicide rates among older people ranged from
50 to 418 per 100 000 among women and from 113 to 326
per 100 000 among men.17–21 Oyama and associates17–21 devel-
oped a universal suicide prevention program, which included a
screening component adapted from the WHO World Mental
Health Survey.24 The program involved screening for depression, follow-up with mental health care or psychiatric treatment, and psychoeducation in the community setting. The
control communities had similar demographic characteristics
and were in the same geographic region as the intervention
communities, but they received no components of the pro-
Table 1 (part 1 of 2): Characteristics of studies included in a meta-analysis of the benefit of screening for depression
S tu d y p o p u l a ti o n
Study
Description
Outcomes
Definition
Evaluation
Definition
Results
Oyama et al.19 (5-yr
quasi-experimental
study in Matsudai,
Japan [rural])
Total person-years:
11 567 for
intervention, 15 055
for control
Age, mean: NR
Age, range: ≥ 65 yr
Age, median: NR
Sex, female: 57.6%
Ethnicity: Japanese
Education: NR
Dx: major and minor
depression
Older (≥ 65 yr)
residents in 6 rural
municipalities of
southwest and central
Japan
Intervention: mental
health workshop,
referral to general
practitioner or followup interview with PHN
Exclusions: severely
disabled or
hospitalized cases
were excluded from
the study
Screening instrument:
SDS
Other rating: RDC
Confirmatory exam:
ICD-9
No. of follow-ups: 10
No. of stages: two 10yr
Main outcome:
Change in risk of
completed suicide
Age-adjusted IRRs
of completed
suicide before and
after intervention or
control
Main outcome:
Risk of completed suicide
in intervention area
reduced by 70% among
women, no significant
change among men
Intervention: IRR 1.02
(95% CI 0.49–2.13) for
men and 0.30 (95% CI
0.14–0.67) for women
Control: No significant
change
Oyama et al.20 (10-yr
quasi-experimental
study in Yasuzuka,
Japan [rural])
Total person- years:
9791 for intervention,
16 032 for control
Age, mean: NR
Age, range: ≥ 65 yr
Age, median: NR
Sex, female: NR
Ethnicity: Japanese
Education: NR
Dx: major and minor
depression
Older (≥ 65 yr)
residents of
agricultural rural area
in Japan with high
suicide rate
Intervention: (a) public
health education from
1991 to 2000 and (b)
screening for
depression with followup from 1991 to 1997
Exclusions: NR
Screening instrument:
SDS
Other rating: RDC
Confirmatory exam:
ICD-9
No. of follow-ups: 7
No. of stages: two 10yr
Main outcome:
Change in risk of
completed suicide
Age-adjusted IRRs
of completed
suicide before and
after intervention or
control
Main outcome:
Risk of completed suicide
in intervention area
reduced by 64% among
women, no significant
change among men
Intervention: IRR 0.51
(95% CI 0.22–1.19) for
men and 0.36 (95% CI
0.14–0.93) for women
Control: No significant
change
Oyama et al.17 (10-yr
quasi-experimental
study in Joboji town,
Japan [rural])
Total person- years:
9721 for intervention,
17 166 for control
Age, mean: NR
Age, range: ≥ 65 yr
Age, median: NR
Sex, female: 50.8%
Ethnicity: Japanese
Education: NR
Dx: depression
(unspecified)
Older (≥ 65 yr)
residents of
agricultural rural area
in Japan with high
suicide rate
Intervention: 2-step
depression screening
performed by PHN and
psychiatrist with followup by psychiatrist
every 3 yr in targeted
district of intervention
municipality, health
education and
emphasis on suicide
taboo every year in 10yr period from 1990
Exclusions: Older
people receiving social
welfare
Screening instrument:
SDS
Other rating: SADD
Confirmatory exam:
ICD-9
No of follow-ups: 10
No. of stages: three
5-yr
Main outcome:
Change in suicide
rates
Age-adjusted IRRs
of completed
suicide before and
after intervention or
control
Main outcome:
Risk of suicide in
intervention area reduced
by 73% among men and
by 76% among women
during implementation
decade (relative to preimplementation decade)
Intervention: IRR 0.27
(95% CI 0.08–0.88) for
men and 0.24 (95% CI
0.11–0.52) for women
Control: No significant
change
Continued
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Table 1 (part 2 of 2): Characteristics of studies included in a meta-analysis of the benefit of screening for depression
S tu dy pop ul ati on
Study
Outcomes
Description
Definition
Evaluation
Definition
Results
Oyama et al.18 (5-yr
quasi-experimental
study in Nagawa town,
Japan [rural])
Total person- years:
1982 for intervention,
16 754 for control
Age, mean: NR
Age, range: ≥ 65 yr
Age, median: NR
Sex, female: 59%–
60.8%
Ethnicity: Japanese
Education: NR
Dx: depression
(unspecified)
Older (≥ 65 yr)
residents of
agricultural rural area
in Japan with high
suicide rate
Intervention: 2-step
screening for
depression and followup by PHN, mental
health workshop 3 or 4
times a year, group
activity program once
a month
Exclusions: NR
Screening instrument:
SDS
Other rating: RDC
Confirmatory exam:
ICD-9
No. of follow-ups: 6
No. of stages: two 6yr
Main outcome:
Change in risk of
completed suicide
Age-adjusted IRRs
of completed
suicide before and
after intervention or
control
Main outcome:
Risk of suicide in
intervention area reduced
by 74% among women,
no significant change
among men
Intervention: IRR 0.48
(90% CI 0.10–2.31) for
men and 0.26 (90% CI
0.07–0.98) for women
Control: No significant
change
Oyama et al.21 (5-yr
quasi-experimental
study in 6 rural
municipalities of the
Sanpachi Second
Medical Zone, Japan
[rural])
Total person-years:
28 838 for
intervention, 27 633
for control
Age, mean: NR
Age, range: ≥ 60 yr
Age, median: NR
Sex, female: 57.5%
Ethnicity: Japanese
Education: NR
Dx: depression
(unspecified)
Older (≥ 60 yr)
residents living in 6
rural municipalities of
Sanpachi Second
Medical Zone of Japan
(mostly agricultural
region with high
suicide rate)
Intervention: (a) health
education and (b)
screening for
depression with followup, using community
resources of primary
care and public health
nursing
Exclusions: NR
Screening instrument:
CES-D, DSS, SDS,
GDS-5
Other rating: CIDI
Confirmatory exam:
ICD-10
No. of follow-ups: 2
No. of stages: two 2yr
Main outcome:
Change in risk of
completed suicide
Age-adjusted IRRs
of completed
suicide before and
after intervention or
control
Main outcome:
Risk of suicide in
intervention region
reduced by 61% among
men; no significant
change among women
Intervention: IRR 0.39
(90% CI 0.18–0.87) for
men and 0.49 (90% CI
0.19–1.22) for women
Control: No significant
change
Note: CES-D = Center for Epidemiologic Studies Depression Scale, CI = confidence interval, CIDI = Composite International Diagnostic Interview, DSS = Depression and
Suicide Screen, Dx = diagnosis, GDS-5 = 5-item Geriatric Depression Scale,22 ICD = International Statistical Classification of Diseases, IRR = incidence rate ratio, NR = not
reported, PHN = public health nurse, RDC = Research Diagnostic Criteria, SADD = schedules of Standardized Assessment of Patient with Depressive Disorders, SDS = Selfrating Depression Scale.23
gram. The duration of the included studies ranged from 4 to
20 years (over the period 1978 to 2006). The overall aim of
the studies was to evaluate the effectiveness of the community-based depression screening program over both the short
term and the long term. The outcome of interest was completed suicides, determined from registrations of suicides at
local public health centres. The diagnoses in the registry were
based on the International Classiication of Diseases, Ninth
Revision, in which conirmed and probable suicides were
grouped together.
All 5 studies used a pre- and post-implementation design.
In all studies, more than 60% of men and more than 80% of
women within the targeted groups of residents participated in
the program during the implementation period.
All 5 studies involved implementation of the suicide prevention program, which had a 2-step process for screening
and follow-up for depression. In the irst step, older residents
within the selected communities were called with an invitation
to participate in an educational health workshop on the signs
of and possible treatments for depression and suicide risk and
also on how to use mental health services. Following the
workshop, those who agreed to participate in the program
completed the Japanese version of the Zung Self-rating
Depression Scale,23 a 20-item scale that measures affective,
psychologic and somatic symptoms associated with depression
(used in all 5 of the included studies17–21), or the 5-item Geriatric Depression Scale22 (used in 1 of the included studies21).
Those who did not attend the workshop were contacted the
following day and asked to participate in the program. Examiners then visited all those who agreed to participate and conducted the suicide prevention program according to the same
procedures. There were several examiners, including psychiatrists and public health nurses.
In the second step, public health nurses conducted a mental health assessment for each enrolled participant who had a
positive screening result on the Self-rating Depression Scale.
The nurses used Japanese translations of a standardized
assessment for patients with depressive disorders25 and made a
clinical decision about whether a medical examination by a
psychiatrist was necessary.
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The meta-analysis of the target population involved 70 053
person-years and 65 completed suicides in the intervention
groups and 113 324 person-years and 145 completed suicides
in the control groups during the respective implementation
periods. On the basis of the information provided in the
included studies (speciically, average population sizes over 5
years and average percentage of people over the age of 65), we
estimated that the overall sample sizes were 18 311 for the
intervention groups and 19 736 for the control groups. The
studies reported 6 sex- and age-speciic target population
groups (men and women aged 65–74, 75–84 and ≥ 85), with
the exception of one study,21 which used age groups 60–69, 70–
79 and ≥ 80. All 5 studies presented data stratiied by age, sex
and time periods for baseline and program implementation.
Log RRR
SE
Oyama et al.17
–1.23
0.43
21.5
0.29 (0.13–0.68)
Oyama et al.19
–0.31
0.41
23.2
0.73 (0.33–1.64)
Oyama et al.
20
–0.19
0.38
26.0
0.83 (0.39–1.74)
Oyama et al.
18
–0.99
0.68
9.9
0.37 (0.10–1.41)
Oyama et al.
21
–1.07
0.46
19.4
0.34 (0.14–0.84)
100.0
0.50 (0.32–0.78)
Study
Weight (%)
Overall (I2 = 21%)
Favours Favours
experimental control
RRR (95% CI)
0.01
Test for overall effect: Z = 3.06 (p = 0.002)
0.1
10
1
100
RRR (95% CI)
Figure 2: Meta-analysis of the effect of community-based suicide prevention programs, including screening for depression, on suicide rates
reported in cohort studies. A rate ratio (RR) less than 1.0 indicates a benefit of suicide prevention programs. CI = confidence interval; RRR = ratio
of rate ratios (rate ratio for intervention divided by rate ratio for control), where RRR less than 1.0 indicates a benefit of suicide prevention programs; SE = standard error.
Study
Log RRR
Men (non-adjusted)
Oyama et al.17
–1.36
Oyama et al.20
0.42
Oyama et al.19
–0.18
Oyama et al.18
–0.30
Oyama et al.21
–0.91
Overall (men) (I2 = 21%)
Women (non-adjusted)
Oyama et al.17
–1.15
–0.46
Oyama et al.19
–1.58
Oyama et al.18
–0.87
Oyama et al.20
Oyama et al.21
–1.25
Overall (women) (I2 = 0%)
Overall (I2 = 0%)
SE
Weight (%)
RRR (95% CI)
0.69
0.54
0.57
1.01
0.62
8.6
14.1
12.7
4.0
10.7
50.1
0.26 (0.07–0.99)
1.52 (0.53–4.39)
0.84 (0.27–2.55)
0.74 (0.10–5.36)
0.40 (0.12–1.36)
0.67 (0.35–1.27)
0.56
0.61
0.94
0.57
0.70
13.1
11.1
4.7
12.7
8.4
49.9
0.32 (0.11–0.95)
0.63 (0.19–2.09)
0.21 (0.03–1.30)
0.42 (0.14–1.28)
0.29 (0.07–1.13)
0.37 (0.21–0.66)
100.0
0.51 (0.34–0.75)
Favours
experimental
0.05
0.2
Favours
control
1
5
20
RRR (95% CI)
Figure 3: Meta-analysis of the effect of community-based suicide prevention programs, including screening for depression, on suicide rates by sex,
as reported in cohort studies. A rate ratio (RR) less than 1.0 indicates a benefit of suicide prevention programs. CI = confidence interval; RRR = ratio
of rate ratios (rate ratio for intervention divided by rate ratio for control), where RRR less than 1.0 indicates a benefit of suicide prevention programs;
SE = standard error.
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None¶
No serious
imprecision§
Very serious‡
Imprecision
Indirectness
Note: CI = confidence interval, RRR = ratio of rate ratios.
*The quality assessment tools identified a few concerns (e.g., selection of non-exposed cohort, blinding and reporting of withdrawals and drop-outs); however, the evidence was not downgraded for these reasons.
†Heterogeneity statistics were not significant: τ2 = 0.05, χ2 = 5.04, df = 4 (p = 0.28); I2 = 2%.
‡Directness was downgraded because of concerns about population characteristics. The included papers all involved older populations in rural areas of Japan, which are unlikely to be representative of Canadians at average
or high risk for depression. Directness was downgraded further because of concerns regarding community-based screening for depression: The studies included in the analysis evaluated the effectiveness of community-based
programs to screen 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, any observed reduction in
suicide rates could not be attributed solely to the screening component of these programs.
§The number of events was small (< 300, which is the threshold rule-of-thumb value for dichotomous outcomes); however, with regard to the specific outcome, the evidence was not downgraded.
¶Funnel plot of the comparison indicated potential asymmetry and thus potential publication bias. However, the number of papers (n = 5) was too small to assess publication bias with confidence (≥ 10 papers being the
threshold rule-of-thumb value).
Control
65/70 053 145/113324 RRR 0.50 1 fewer Very
(0.09%)
(0.13%)
(0.32– per 1000 low
0.78)
(range 0
fewer to 1
fewer)
Critical
Relative
(95% CI) Absolute Quality Importance
Effect
Inconsistency
No serious
inconsistency†
No
serious
risk of
bias*
Observational
517–21
We found no direct evidence for beneit of screening in the
average-risk population; rather, we identiied 5 studies of
older populations conducted by the same primary researcher
in rural Japan. Although these 5 studies met the inclusion criteria for our review, their results provide limited evidence on
the effectiveness of screening for depression in the averagerisk population or high-risk groups. The potential generaliz-
Overall (follow-up 4–20 yr; assessed with community-based depression screening)
Interpretation
Design
According to the GRADE system for assessing quality, observational evidence (including evidence from studies with a
cohort design) begins with a “low” rating. We downgraded the
rating because of indirectness, given that the included studies
all involved older populations in a rural Japanese setting, who
are unlikely to be representative of Canadians. We also downgraded the evidence because the studies used communitybased depression screening programs that incorporated education and treatment; as such, their results cannot be
attributed solely to the screening component of the programs.
Thus, the overall GRADE rating applied to this evidence was
very low quality (see Table 2).
Screening
(older
persons)
GRADE rating
Other
considerations
The second question of interest for this review was “What is
the evidence for harm (i.e., decline in clinical outcomes) of
screening for depression in asymptomatic adults from the
general population, in either primary care or other outpatient
settings?” We found no studies meeting our inclusion criteria
that could help to answer this question.
Risk of
bias
Harms of screening
No. of
studies
We found no studies that examined the beneits of screening
high-risk populations (deined using the factors in Appendix
2) versus not screening.
No. of patients/personyears
High-risk populations
Quality assessment
The outcome measure in each study was an IRR based on
binary data (i.e., suicide/no suicide, calculated for both implementation and control groups before and after the intervention).
There was no signiicant heterogeneity among the studies (I2 =
21%, χ2 = 5.04, p = 0.28). When the data for men and women
were analyzed separately, there was no signiicant heterogeneity
among the studies (for men, I2 = 21%, χ2 = 5.07, p = 0.28; for
women, I2 = 0%, χ2 = 1.41, p = 0.84). Publication bias could not
be assessed because the number of included studies was small.
The difference between pooled IRRs and corresponding
95% CIs for completed suicide was calculated using the
generic inverse variance weighting method for the overall
study population and for women and men separately. The
pooled data from the 5 studies17–21 showed a statistically signiicant reduction in the number of completed suicides after
implementation of the community-based depression screening program (RRR 0.50, 95% CI 0.3–0.78) (Figure 2). RRRs
also indicated a signiicant reduction in the suicide rate among
women (RRR 0.37, 95% CI 0.21–0.66) but no signiicant
effect among men (RRR 0.67, 95% CI 0.35–1.27) (Figure 3).
Table 2: GRADE evidence profile for the effect of community-based suicide prevention programs, including screening for depression, on the incidence of suicide
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ability of the indings of these studies should be considered
with caution, as Japan has a national suicide rate much higher
than that in Canada or the United States. Among Japanese
women 75–84 years of age, for whom beneit of screening was
observed in the included studies, the suicide rate is more than
7 times higher than among Canadian women of the same age
group (23.4 v. 3.3 per 100 000, respectively).26 In addition, the
geographic regions included in the study had average rates of
suicide much higher than even the Japanese average.17–21 We
can draw no conclusions about the potential harms of screening for depression, as we found no studies of such harms that
met our inclusion criteria.
These results are consistent with previous guidelines and
evidence reviews. The 2009 systematic evidence review of the
US Preventive Services Task Force27 found no evidence of any
beneit of screening for depression in the absence of treatment programs. The lack of direct evidence to support general screening programs has also been recognized by the
National Institute for Health and Care Excellence28 and the
Scottish Intercollegiate Guidelines Network;29 neither of these
organizations recommend screening of asymptomatic people
in the general population. The National Institute for Health
and Care Excellence guideline for people with chronic illness
recommended that physicians remain alert to the possibility of
depression,30 and another guideline for perinatal women31 recommended screening women postpartum, yet those recommendations were based on indirect evidence of a beneit of
treatment, rather than direct evidence of effectiveness of
screening or case-inding for depression.
Limitations
The indings of this review are affected by the limitations of
the literature search and of the studies that were included.
Because of resource limitations, we limited our search to
papers written in English or French, as those could be assessed
by the team. It is possible that we missed papers written in
other languages.32 We chose 1994 as the start date for the
search, as that was the publication date for the fourth edition
of the Diagnostic and Statistical Manual of Mental Disorders,
which changed the deinition of major depression.33 The studies that were reviewed here evaluated the effectiveness of community-based depression screening programs that incorporated screening for depression, follow-up with mental health
care or psychiatric treatment, and health education in community settings in rural Japan that had higher-than-average suicide rates. As such, the observed reduction in suicide rates or
recovery from depression cannot be attributed solely to the
screening component of these programs. As well, given that
the program involved community psychoeducation, it is likely
that people in the area were more aware of depression and suicide, which may have altered the reporting of deaths as suicide.
Conclusion
The ultimate goal of screening for depression is to reduce
associated morbidity and mortality. This review found limited
evidence to estimate the effectiveness of screening for depression in primary care among individuals at average risk for
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depression, no evidence for screening in high-risk populations
and no evidence of the harms of screening. Randomized controlled trials comparing screening and no screening should
help to clarify these issues. Future research must have a
broader demographic, geographic and cultural scope. Trials
on the effectiveness of screening among people who are at
increased risk of major depressive disorder are also needed to
help in the early diagnosis and treatment of those most likely
to be affected by depression. More evidence is needed on the
harms of screening for depression (e.g., false positive rates)
and the related potential for unnecessary, and possibly harmful, diagnostic and therapeutic procedures. Finally, more
research on the most effective method of screening for
depression in relation to clinically important outcomes is
needed in populations with increased risk of depression.
References
1. Patten SB, Wang JL, Williams JV, et al. Descriptive epidemiology of major
depression in Canada. Can J Psychiatry 2006;51:84-90.
2. Vasiliadis HM, Lesage A, Adair C, et al. Do Canada and the United States differ
in prevalence of depression and utilization of services? Psychiatr Serv 2007;
58:63-71.
3. MacMillan HL, Patterson CJ, Wathen CN, et al. Screening for depression in
primary care: recommendation statement from the Canadian Task Force on
Preventive Health Care. CMAJ 2005;172:33-5.
4. Canadian Task Force on Preventive Health Care, Joffres M, Jaramillo A, Dickinson J, et al. Recommendations on screening for depression in adults. CMAJ
2013;185:775-82.
5. Sartorius N, Ustun TB, Lecrubier Y, et al. Depression comorbid with anxiety:
results from the WHO study on psychological disorders in primary health care.
Br J Psychiatry Suppl 1996;Jun:38-43.
6. National Collaborating Centre for Mental Health. Depression: management of
depression in primary and secondary care [NICE Clinical Guidelines, no. 23]. London (UK): National Institute for Health and Clinical Excellence; 2004. Rep.
no.: CG90.
7. National Collaborating Centre for Mental Health. Depression. The treatment and
management of depression in adults (updated edition) [Clinical Guideline 90]. London (UK): National Institute for Health and Clinical Excellence; 2009. Available: http://publications.nice.org.uk/depression-in-adults-cg90 (accessed 2013
Dec. 16).
8. Palmer SC, Coyne JC. Screening for depression in medical care: pitfalls, alternatives, and revised priorities. J Psychosom Res 2003;54:279-87.
9. O’Connor EA, Whitlock EP, Gaynes BN, et al. Screening for depression in adults and
older adults in primary care: an updated systematic review [Evidence synthesis no. 75.
AHRQ report no. 10-05143-EF-1]. Rockville (MD): Agency for Healthcare
Research and Quality; 2009.
10. Pignone MP, Gaynes BN, Rushton JL, et al. Screening for depression in adults:
a summary of the evidence for the U.S. Preventive Services Task Force. Ann
Intern Med 2002;136:765-76.
11. Gilbody S, House AO, Sheldon TA. Screening and case inding instruments for
depression. Cochrane Database Syst Rev 2005;(4):CD002792.
12. Patten SB, Juby H. A proile of clinical depression in Canada. Calgary (AB): Department of Community Health Sciences and Psychiatry, University of Calgary;
2008. Available: http://hdl.handle.net/1880/46327 (accessed 2013 Apr. 18).
13. Higgins JPT, Green S, editors. Cochrane handbook for systematic reviews of interventions. Version 5.1.0 ed. New York (NY): Cochrane Collaboration and WileyBlackwell; 2008 [updated 2011].
14. Guyatt GH, Oxman AD, Vist GE, et al. GRADE: an emerging consensus on
rating quality of evidence and strength of recommendations. BMJ 2008;
(336):924-6.
15. Shaffer HJ, Vander Bilt J, Hall MN. Gambling, drinking, smoking and other
health risk activities among casino employees. Am J Ind Med 1999;36:365-78.
16. Wells G, Shea B, O’Connell D, et al. The Newcastle–Ottawa Scale (NOS) for
assessing the quality of nonrandomised studies in meta-analyses. Ottawa (ON):
Ottawa Hospital Research Institute; 2000.
17. Oyama H, Koida J, Sakashita T, et al. Community-based prevention for suicide
in elderly by depression screening and followup. Community Ment Health J
2004;40:249-63.
18. Oyama H, Ono Y, Watanabe N, et al. Local community intervention through
depression screening and group activity for elderly suicide prevention. Psychiatry
Clin Neurosci 2006;60:110-4.
19. Oyama H, Fujita M, Goto M, et al. Outcomes of community-based screening
for depression and suicide prevention among Japanese elders. Gerontologist 2006;
46:821-6.
CMAJ OPEN
Research
20. Oyama H, Goto M, Fujita M, et al. Preventing elderly suicide through primary
care by community-based screening for depression in rural Japan. Crisis 2006;
27:58-65.
21. Oyama H, Sakashita T, Hojo K, et al. A community-based survey and screening
for depression in the elderly: The short-term effect on suicide risk in Japan.
Crisis 2010;31:100-8.
22. Hoyl MT, Alessi CA, Harker JO, et al. Development and testing of a ive-item
version of the geriatric depression scale. J Am Geriatr Soc 1999;47:873-8.
23. Zung WW. A self-rating depression scale. Arch Gen Psychiatry 1965;12:63-70.
24. Kessler RC, Ustun TB. The World Mental Health (WMH) survey initiative
version of the World Health Organization (WHO) Composite International
Diagnostic Interview (CIDI). Int J Methods Psychiatr Res 2004;2:93-121.
25. Gastpar M. The ICD-9 and the SADD-criteria for depression. Acta Psychiatrica
Scand Suppl 1983;310:31-41.
26. Shah A. A replication of the relationship between elderly suicides rates and
elderly dependency ratios: a cross-national study. J Inj Violence Res 2010;2:19-24.
27. O’Connor EA, Whitlock EP, Beil TL, et al. Screening for depression in adult
patients in primary care settings: a systematic evidence review. Ann Intern Med
2009;151:793-803.
28. National Collaborating Center for Mental Health. The NICE guideline on the
management and treatment of depression in adults (updated edition) [National Clinical Practice Guideline 90]. Leicester (UK): British Psychological Society; 2010.
Available: www.nice.org.uk/nicemedia/live/12329/45896/45896.pdf (accessed
2013 Dec. 16).
29. Scottish Intercollegiate Guidelines Network (SIGN). Management of perinatal
mood disorders [Report no. 127]. Edinburgh (Scotland): SIGN; 2012.
30. National Collaborating Centre for Mental Health. Depression in adults with a chronic
physical health problem: treatment and management [NICE Clinical Guidelines, no.
91]. London (UK): National Institute for Health and Care Excellence; 2009.
31. National Collaborating Centre for Mental Health. Antenatal and postnatal mental
health: clinical management and service guidance [NICE Clinical Guidelines, no.
45]. London (UK): National Institute for Health and Clinical Excellence; 2007.
32. Moher D, Pham B, Klassen TP, et al. What contributions do languages other
than English make on the results of metaanalyses? J Clin Epidemiol 2000;53:96472.
33. Wakeield JC, Schmitz MF, Baer JC. Did narrowing the major depression
bereavement exclusion from DSM-III-R to DSM-IV increase validity? Evidence from the National Comorbidity Survey. J Nerv Ment Dis 2011;199:66-73.
Afiliations: McMaster Evidence Review and Synthesis Centre and
Department of Clinical Epidemiology and Biostatistics (Keshavarz, Rice, Ali,
Shannon, Raina); McMaster Evidence Review and Synthesis Centre and
School of Nursing (Fitzpatrick-Lewis); Department of Psychiatry and Behavioural Neurosciences (Streiner), McMaster University, Hamilton, Ont.;
Department of Psychiatry (Streiner), University of Toronto, Toronto, Ont.
Contributors: Homa Keshavarz, Donna Fitzpatrick-Lewis, David
Streiner, Maureen Rice, Usman Ali, and Parminder Raina were involved
in conceptualizing the study, analyzing the data and writing the manuscript. Harry Shannon contributed to analyzing the data and provided
manuscript revisions. Homa Keshavarz and Donna Fitzpatrick-Lewis
were also involved in designing the methods, collecting the data and coordinating the project. Maureen Rice performed the literature search. All of
the authors approved the inal manuscript.
Funding: This review was funded by the Canadian Institutes of Health
Research. The views expressed herein are the opinions of the authors and
do not necessarily represent the views of the Canadian Institutes of
Health Research.
Acknowledgements: The authors thank Catherine Salmon, Sara Kaffashian and Robert Stevens for reviewing the titles and abstracts. Leah
MacDonald formatted the large evidence review, as well as the manuscript
submitted for publication. Members of the Canadian Task Force on Preventive Health Care, including Michel Joffres, chairperson of the Depression Screening Guideline Working Group, contributed to protocol development and/or discussion of indings. Lesley Dunield and Alejandra
Jaramillo, Public Health Agency of Canada oficers, were involved with
performing the review and creating the guideline. Parminder Raina holds
a Tier 1 Canada Research Chair in Geroscience and the Raymond and
Margaret Labarge Chair in Research and Knowledge Application for
Optimal Aging.
Supplemental information: For reviewer comments and the original
submission of this manuscript, please see www.cmajopen.ca/content
/1/4/E159/suppl/DC1
Editor’s note: This paper is based on a full systematic review entitled
“Screening for depression,” which can be found at: http://canadiantaskforce
.ca/guidelines/depression/
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