Canadian Task Force on Preventive Health Care

Structured Abstract

Early Detection of Depression
 

Prepared by John W. Feightner, MD, MSc, FCFP, Department of Family Medicine, The University of Western Ontario

These recommendations were finalized by the Task Force in January 1994

Contents
 

 Objective

To make recommendations regarding routine screening for depression in asymptomatic adults, updating a report published in May, 1990.

 Burden of Suffering

The lifetime prevalence of clinically significant depression is 15% to 30%; it is about twice as common among women as among men, and is thought to have increased among children and adolescents. People who are single, divorced, separated, seriously ill, recently bereaved or those with a family history of depression have a greater incidence than others. Depressed individuals frequently present with physical symptoms, which may make diagnosis more difficult, resulting in diagnostic testing or treatment for other illnesses. Affected people are more likely than others to be suicidal: 30% to 70% of people who have committed suicide were previously identified as having major depression. In Canada, in 1986, suicide accounted for an estimated 97,600 potential years of life lost among men and 25,300 among women.

 Options

To screen or not to screen for depression using the General Health Questionnaire (GHQ) or the Zung Self-Rating Depression Scale.

 Outcomes

Validity, sensitivity and specificity of questionnaires; physician detection and treatment of depression (p451).

 Evidence

MEDLINE was searched up to May, 1993 using the MeSH headings "depression" and "mass screening". Study results were synthesized in table or graphic format only.

Recommendations were graded as:
A
 Good evidence to support the recommendation that the condition be specifically considered in a PHE. 
B
 Fair evidence to support the recommendation that the condition be specifically considered in a PHE. 
C
 Poor evidence regarding inclusion or exclusion of the condition in a PHE, but recommendations may be made on other grounds. 
D
 Fair evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE. 
E
 Good evidence to support the recommendation that the condition be specifically excluded from consideration in a PHE. 
Quality of evidence was rated according to 5 levels:
I
 Evidence from at least 1 properly randomized controlled trial (RCT). 
II-1
 Evidence from well-designed controlled trials without randomization. 
II-2
 Evidence from well-designed cohort or case-control analytic studies, preferably from more than 1 centre or research group. 
II-3
 Evidence from comparisons between times or places with or without the intervention. Dramatic results in uncontrolled experiments could also be included here. 
III
 Opinions of respected authorities, based on clinical experience, descriptive studies or reports of expert committees. 

 Values

The 13-member Task Force of experts in family medicine, geriatric medicine, pediatrics, psychiatry and epidemiology used an evidence-based method for evaluating the effectiveness of preventive health care interventions. Recommendations were not based on cost-effectiveness of options. Patient preferences were not discussed.

Background papers providing critical appraisal of the evidence and tentative recommendations prepared by the chapter author were pre-circulated to the members. Evidence for this topic was presented and deliberated upon in 1- to 2-day meetings, 2 to 3 times per year from January 1993 to June 1993. Consensus was reached on final recommendations.

 Benefits, Harms, and Costs

The validity of many self-administered questionnaires has not been fully established. Using clinical criteria as the diagnostic standard, questionnaires have shown sensitivities of 64% to 91% and specificities of 56% to 82%. Correlations with other tests or with clinical assessments ranged from 0.40 to 0.89 (p451).

4 RCTs evaluated effects of the routine use of a screening questionnaire on the detection and management of depression. In 3 of these trials, patients completed the GHQ, and the results were presented to the physician before seeing the patient. A study of 1242 patients attending an inner-city primary care clinic found that GHQ results had an effect on physician detection of psychological problems only for those ³ 65 years, and ultimately had no effect on patient management for any age group [3]. Similarly, a study of 1469 patients in a primary care office found no effect of physician knowledge of a positive GHQ result on detection of psychological distress [4]. A methodologically weaker study of 1093 patients found that 16% of patients were given a diagnosis of psychiatric illness when the physician had no GHQ results; an additional 11% of patients were diagnosed after GHQ results were given to the physician [5]. Another study found that when informed of a positive patient score on the Zung-Self-Rating Depression Scale, physicians detected depression in more patients (68% of 102) than when they were uninformed (15% of 41). This study was flawed in design and execution [6]. (p451)

Potential harms and costs were not discussed.

 Recommendations

Recommendation grade [A, B, C, D, E]  and level of evidence [I, II-1, II-2, II-3, III] are indicated after each recommendation. Citations in support of individual recommendations are identified in the guideline text.

 Validation

Recommendations were peer-reviewed and are similar to those of the 1989 U.S. Preventive Services Task Force.

 Sponsors

The Canadian Task Force on Preventive Health Care developed this guideline with funding from Health Canada.

 Selected References

Source Document Other

Link to Full Text of this review

Link to Summary Table of Recommendations of this review

Link to Selected References list of this review

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