lecture 3 - measuring anxiety and depression and introduction to validity of psychological tests Flashcards
An example of a self-report scale for anxiety and
depression: The HADS
The Hospital Anxiety and Depression Scale (HADS; Zigmond &
Snaith, 1983) is a brief (14 item) self-report scale
- Here are some example items from the Depression scale:
I can laugh and see the funny side of
things:
As much as I always could (0)
Not quite so much now (1)
Definitely not so much now (2)
Not at all (3)
I feel cheerful:
Not at all (3)
Not often (2)
Sometimes (1)
Most of the time (0)
examples of items comprising the HADS
anxiety items / depression items
-I feel tense or ‘wound up’
- I still enjoy the things I used to enjoy
-I get a sort of frightened feeling as if something awful is about to happen
-I can laugh and see the funny side of things
-Worrying thoughts go through my
mind
-I feel cheerful
-I can sit at ease and feel relaxed
- I feel as if I am slowed down
-I get a sort of frightened feeling like
‘butterflies’ in the stomach
-I have lost interest in my appearance
-I feel restless as if I have to be on the move
-I look forward with enjoyment to
things
-I get sudden feelings of panic
-I can enjoy a good book or radio or
TV programme
why use self report mood scales
-They are quick to administer
-They are cheap to administer
-They are generally reliable
-The client / patient directly reports their feelings rather than the being
filtered through the “lens” of a clinician
-There is a general agreement among psychologists that we should use multiple indicators whenever possible – so therefore use clinician’s interview
/ ratings and self-reports
-A patient’s self-report scale responses can be raised in the clinical interview
the hospital anxiety depression scale (HADS)
-need to reflect/ reverse score
In many self-report scales some items need to be “reflected” or “reverse- scored”:
I feel cheerful - I feel as if I’m slowed down
(0) most of the time …… (4) Not at all
To counter effects of acquiescence bias (“yeah-saying”)
-As an attempt to have respondents pay attention to the items
As a check on inattention / lack of motivation
Scored on a 4 point scale (0 – 3) – remember to reverse scores that need reversed
reliability of the HADS
-how is reliability measured for it
-is HADS reliable? (numbers)
Reliability of self-report mood scales is assessed in same way as ability tests
That is, Cronbach’s alpha is computed for anxiety, depression scales and overall
Is the HADS reliable?
It is fairly reliable but not as high for some other self-report scales
Crawford et al. 2009 reported Cronbach’s alpha of 0.84 for the anxiety scale and 0.78 for depression scale in a general population sample (n = 3822 )
Reliability of total scale (anxiety and depression combined) was 0.87 (what does that tell us?)
what type of symtomps does HADS exclude
-Provide an example of how a medical issue might influence HADS responses.
-does HADS measure independent dimensions of anxiety and depression?
HADS was developed for use in general medical settings
Therefore the items were chosen so that effects of a medical condition did not masquerade as depression or anxiety
Hence does not contain items that measure somatic or vegetative symptoms(focus is firmly on mood)
people often saying they felt anxious/ depressed-but this was because of other reasons
-feeling like that is quite different to actually having clinical anxiety/depression
Very questionable however whether the aim was achieved
For example, almost any major medical problem would lead people to endorse
“I feel as if I am slowed down” ?
Zigmond & Snaith (1983) stated that the HADS measures “ independent
dimensions of anxiety and depression” (it doesn’t! we will return to this issue)
how is the HADS measured
Zigmond & Snaith’s original cut-offs for the HADS
(the same cut-offs are used for the Anxiety and Depression scales):
normal- 0-7
mild 8-10
moderate 11-15
severe 16 and above
Cut-offs based on clinicians’ ratings of a sample given the HADS, but details are vague
The cut-off for “Mild” is very inclusive and should not be used to establish “caseness”
11 is maybe serious enough to consider it clinical
Crawford et al. (2001) reported that 33% of their general adult population sample
scored 8 or above on the Anxiety scale
assessing the validity the psychological tests
-validity
-validation is the process of..
Validity – does a test measures what it claims to measure
A valid test shown to be valid for a particular use, population and time.
Validation is the process of acquiring evidence and evaluation
types of validity
Types of validity – all add to the pool of evidence
* Content validity -how do the items in a test relate to the construct we are measuring
* Criterion-related validity
* Construct validity
But others too:
* E.g. concurrent, predictive, ecological, convergent, discriminant, face etc.
what is face validity
-when is it desirable / why and why is it not at the same time
Face Validity – does test appear to measure what it claims to measure (doesnt have to measure it but does it look like its ??)
Face validity is usually desirable (the test will be taken seriously-want people to be engaged etc) also helps people to trust the process
- Potential problem for some neuropsychological tests: can appear like a child’s
game-people might not feel like they are taken seriously - However occasionally face validity is not desirable (e.g., detection of
deception) you want to test people without them faking it etc
Items for EPQ - Do you have many different hobbies?
- Do you stop to think things over
before doing anything? - Are you a talkative person?
content validity
Content validity – does the measure adequately sample the domain of
interest
relationship between test and what construct we are trying to measure
Education, does a test sample everything that was taught
* Depression, do items cover all the core symptoms? Could evaluate by:
* Experts could write and /or review the items
* Or compare items against some formal established criteria
* For example, does a depression scale cover the list of symptoms for a
diagnosis of depression in the Diagnostic and Statistical Manual (DSM)?
DSM-IV criteria for Major Depressive Episode
Five or more of the following present during the same two week period;
symptoms 1 or 2 must be present:
1 Depressed mood most of the day, nearly every day
2 Diminished interest or pleasure in all, or almost all, activities nearly every
day
3 Significant weight loss or gain / significant change in appetite
4 Insomnia or hypersomnia nearly every day
5 Psychomotor agitation or retardation nearly every day
6 Fatigue or loss of energy nearly every day
7 Feelings of worthlessness or excessive guilt nearly every day
8 Diminished ability to think or concentrate or indecisiveness
9 Recurrent thoughts of death or suicidal ideation or a suicide attempt
are symtomps due to a general medical condition included in diagnosos?
Individual symptoms that are “clearly due to a general medical condition” are not
included, nor would a positive diagnosis be made if symptoms arose from the
effects of a substance
what are many of the symptoms concerned with
Note that 4 out of 9 symptoms are concerned with vegetative or psychomotor aspects (traditionally even more emphasis has been placed on these symptoms in
the UK)
Note that you can meet the criteria for major depressive disorder without reporting being depressed!
Note that, for 3 of the symptom areas, a deviation from the norm in either direction would count towards a diagnosis (i.e., weight/psychomotor/sleep)
