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)
items comprising the HADS- anxiety 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 - Worrying thoughts go through my
mind - 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 feel restless as if I have to be on the
move - I get sudden feelings of panic
depression items
- i still enjoy things i used to enjoy
- i can laugh and see the funny side of things
- i feel cheerful
- i feel as if i am slowed down
- i have lost interest in my appearance
- i look forward with enjoyment to things
- i can enjoy a good book or radio or tv programme
self-report mood scales: why use them?
- 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)
- Very widely used self-report measure
- 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
the hospital anxiety depression scale: reliability
- 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?)
the hospital anxiety depression scale (HADS) cont
- The 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)
- 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)
the HADS
Zigmond & Snaith’s original cut-offs for the HADS (the same cut-offs are used for the Anxiety and Depression scales):
normal= 0-7 score range / cut off
mild = 8-10
moderate = 11-15
severe > 16
- 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” - Crawford et al. (2001) reported that 33% of their general adult population sample
scored 8 or above on the Anxiety scale
assessing the validity of psychological tests- what is 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
what are the types of validity?
- content validity
- criterion related validity
- construct validity
but others too:
- eg concurrent, predictive, ecological, convergent, discriminant, face ect
face validity
- Face Validity – does test appear to measure what it claims to measure
- Face validity is usually desirable (the test will be taken seriously)
- Potential problem for some neuropsychological tests: can appear like a child’s game
- However occasionally face validity is not desirable (e.g., detection of
deception)
items for eysenck personality questionnaire
* Do you have many different hobbies?
- Do you stop to think things over before doing anything?
- Are you a talkative person?
assessing the validity of psychological tests- content validity
content validity does the measure adequately sample the domain of interest
- 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
Some general points on DSM diagnosis of depression
- 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
- 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)
content validity example
Depression scales evaluated against DSM criteria for depression
(derived from Moran & Lambert, 1983
REFER TO SLIDES FOR EXAMPLE TABLE
- Can be seen that two of the scales examined (Hamilton & Beck) do well in terms of content validity when evaluated against DSM criteria
- (Note: The Hamilton is widely used clinician rating scale, not a self-report scale)
- You wouldn’t want to use the Depression Adjective Checklist if assessing a case
for depression - The PHQ-9 is a depression scale which tackles the issue of content validity
directly and explicitly
-The items are designed to index each of the nine DSM symptoms for depression..
