2. Surveillance of mental health
• Mental health – from wellbeing and
coping to distress and disorder
• WHO defined mental health as “a state of wellbeing in which the individual realises
his or her own abilities, can cope with the normal stresses of life, can work
productively and fruitfully, and is able to make a contribution to his or her
community”
3. • Public mental health – enhance wellbeing or
reduce disorders through risk factor
intervention
• Is wellbeing and disorder part of the same
distribution?
• No real attempt to separate them?
• When (WHO) surveys: Disorder and distress
4. Surveillance of mental health
• WHO attempts to monitor mental health
(distress and disorder):
– World Health Survey (WHS),
– World Mental Health Survey (WMH)
– WHS: 2002–2004,70 countries, n = 300 000
individuals, public resource
– WMH:2001-2012; 27 countries, n= 154,000
5. Surveillance of mental health
• Rationale for conducting WHS and WMH
– National prevalence estimates of
disorder/symptoms
– Burden of disorders (function/disability)
– Service utilization and unmet needs
– Social, demographic patterns
– Risk factors for selected disorders(e.g. life-events)
– Cross country comparisons
6. Surveillance of mental health
• Major pillars of WHS and WMH:
– Probability samples
– Comparable (cross-culture invariant) interviews
– Low to high income countries (WB)
– Standardized, lay administered interviews with algorithm-generated disorder
(reliability before validity)
– Diagnostic scales before distress scales
WHS larger, covers depression and selected symtoms. WMH cover full criteria for
more disorders.
7. Probability samples
• Different sampling procedure for each country
• Often Househould surveys (PSU = Hh)
• Double-phase/two-stage sampling
– Requires weight to be (nationally) representative
8. Standardized interviews
• CIDI - Composite International Diagnostic Interview
• Standardized interviews, lay interviewer, face-to-face
• Made simple, allows no additional questions
• Stem questions to save time
• Algorithm produced diagnoses (DSM, ICD)
• Generally acceptable reliability
• Developed from ECA-DIS and NCS-CIDI (US)
• CIDI today dominates psychiatric epidemiology
10. Depression symptoms
5/9 nearly daily, 1 or 2 must be present 2 weeks, mood
should be reflecting a change from normal = Major
depression
11. The WHO WMH-CIDI
• allows the investigator to:
– Measure the prevalence of mental disorders (mood, anxiety, substance,
impulse-control)
– Measure the severity of these disorders
– Determine the burden of these disorders
– Assess service use
– Assess the use of medications in treating these disorders
– Assess who is treated, who remains untreated, and barriers to treatment
https://www.hcp.med.harvard.edu/wmhcidi/
13. • Provides prevalence (and attributed burden, e.g. Disability)
• (Too) high prevalence, large differences. Lifetime range12% to 47.4% (above): 12 month range: 6% to 27%
ref: Kessler et al. The
global burden of mental
disorders: an update
from the WHO World
Mental Health (WMH)
surveys. Epidemiol
Psichiatr Soc. 2009 Jan-
Mar;18(1):23-33.
14. World Health Survey, depression
Ref: Rai et al. Country-
and individual-level
socioeconomic
determinants of
depression: multilevel
cross-national
comparison. BjPy
(2013) 202, 195–203.
15. World Health Survey, psychotic symptoms
• Again, (Too) high prevalence, large differences (truncated list of the 70 countries):
• Ref: Nuevo et al 2012. The Continuum of Psychotic Symptoms in the General Population: A
Cross-national Study. Schizophrenia bulletin. vol. 38 no. 3 pp. 475–485.
16. WMH survey
• Selected results:
– Prevalence is high
– All disorders are associated with burden/disability
– Many disorder remain untreated (’unmet need’)
– Comorbidity is high
– Very large differences between countries
17. Older WHO cross-country mental
health projects
• Double-phase sampling (GHQ-12+CIDI)
• Focus on psychological illness (GHQ-12)
• Illness stability (GHQ-12)
• Not general population, but cross country
• Used GHQ-12 because proven invariant
across countries (CIDI not examined), used in Primary Care
• GHQ-12 scale before disorder:
• sensitive and unspecific
• Established GHQ-12 as the principal:
– Screening tool (Clinical and Double-phase sampling)
– Epidemiological scale for general mental distress
– As a valid screener for (CIDI) common mental disorders
18. General Health Questionnaire
GHQ as surveillance tool of
mental health
With special reference to the
Stockholm Public Health
Questionnaire
20. Psychological wellbeing
• Instruments based on mental health as a
continuum
• Not formulated to capture specific disorder
• Often with focus on broad emotions
• Sometimes include positive emotions (not
happy NE sad)
21. General Health Questionnaire
• A measure of psychological wellbeing?
• Designed to cover: four elements of distress:
depression, anxiety, social impairment, and
hypochondiasis
• Originally developed for primary care
screening for disorder
• Also used as an ‘outcome measure’ in RCTs
• Much used in Surveys – psychiatric distress
23. Revisions: 60 to 30, 20 and 12
• Shortened for easy use (faster for patient)
• Some items were redundant
• Shift from theoretical to empirical basis
(’calibration’)
24. GHQ-12
• All versions have equal number of positively and negatively
phrased questions
• 12 item version does not have any somatic items (indicated by
those which somatic illness)
• Intended to distinguish distress from no distress
• Not intended for diagnosis, but to screen for disorder
• Ask about recent changes from the normal status (state not
trait)….. In last few weeks.
26. How is it scored?
• Likert scoring method
– Ordinal as 0, 1, 2, 3
– Summary index, range 0-36
• Standard (GHQ) scoring
– Dichotomous as 0, 0, 1, 1
– Summary index, range 0-12
• Corrected scoring [chronic/trait]?
– Answering ”no more than usual” to negatively phrased q?
Note: Despite agrement set, no items are reversed
27. Fill out an imaginary respondent
• Score first response 0, second 1 […]or last 3.
• Sum the scores
• Last, count the number of items scored 2 or 3
• (one more detailed, one intuitive (?)
30. Stockholm PHC
• Includes the GHQ-12 since 1990
• Same version as national and other regional
surveys
• Commonly used with cut off point (3 or more,
on the standard score – based on the manual,
i.e. primary care)
• Sometimes high drop out (12%), compared to
national and regional public health surveys
32. GHQ-12 and Depression
• Comparison in Stockholm 1993
• Excellent to acceptable in discriminating depression from non depression
• Sensitivity and specificity was at ≥2 Standard scored points 67.4% and 74.2%
• Gold standard was minor or major depression
33. Other recent validations
• High agreement
• High sensitivity and specificity at the +3 or +4 cut off points
35. Kessler Psychological Distress Scale K6
Developed directly for population health surveys
Targets mood and anxiety disorder
In one study outperformed (the standard) GHQ-12
In other studies similar overall agreement
Main stated advantage: (standard) GHQ scoring produces too many zeros, better with spectum in
the general population as opposed to primary care.
37. How do we choose a cut off point?
• Prevelance
• Where both sensitivity and specificity is high
• Where at least sensitivity is high (screening)
• Where specificity is high (research)
38. Limitations
• GHQ-12 items chosen because they
differentiated between patients and non-
patients (calibration)
• But does it capture one single spectrum
(distress) or several disorders?
• Factor analyses: 1, 2, 3 or 4 dimensions?
• Redundant questions (FoHM GHQ-5)?
39. A well-being index?
• Less general than the name implies
• More specific than well-being/life satisfaction scales
• Asks about moods but not clinical symptoms
• Not specific enough for (clinical)diagnosis
• Intended to capture disorder (diagnoses)
• Usually validated against depression and anxiety (other mood)
• …but often grouped with measures of wellbeing
40. Diagnostic and rating scales contra
register-based psychiatric epidemiology
• Focus on prevalence rather than care-seeking
• Includes less severe individuals (perhaps incorrectly)
• Focus on reliability rather than expert opinion (psychiatrist)
• Produces research diagnosis (if at all) and not treatment diagnosis
41. Summary
• Public mental health surveys
– Disorder Prevalence
– Distress ratings
– Reliable measures, transferable
– General Health Questionnaire common
– More, and less, specific rating scales advocated
– Try to separate disorder/distress from
function/care
