The sensitivity of the K6 as a screen for any disorder in community mental health surveys: a cautionary note.
OBJECTIVE
Short screening instruments, which exclude respondents unlikely to have psychiatric disorders, can make epidemiologic surveys shorter and more cost-effective. The Kessler 6-Item Psychological Distress Scale (K6), a measure of generalized distress, has been proposed for this role and has shown good agreement with the Composite International Diagnostic Interview (CIDI). However, performance of the K6 may vary for individual disorders or combinations of disorders. In this report, we examine the ability of the K6 to detect disorders among respondents in different diagnostic categories.


METHODS
We used data from Cycle 1.2 of the Canadian Community Health Survey to assemble 5 groups of respondents with different 12-month psychiatric disorders (n = 4481). A sixth group comprised those with 2 or more disorders. We examined the sensitivity of the K6 among respondents with an individual disorder as well as those with multiple disorders.


RESULTS
The sensitivity of the K6 varies significantly by disorder; it is highest among respondents with multiple disorders and lowest among those with agoraphobia only.


CONCLUSIONS
Use of the K6 as a screen for the CIDI is likely to result in biased prevalence estimates. However, both instruments should be compared with a third standard to fully assess the benefits and drawbacks of their combination.
Veldhuizen
Scott
S
Health Systems Research and Consulting Unit, Centre for Addiction and Mental Health, Toronto, Ontario, Canada. scott_veldhuizen@camh.net
Cairney
John
J
Kurdyak
Paul
P
Streiner
David L
DL
D000293:Adolescent; D000328:Adult; D003156:Community Mental Health Services; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D001523:Mental Disorders / Q000175:diagnosis* / Q000453:epidemiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires