Scale Fail

Please do yourself a favour, and watch Old People’s Home For 4 Year Olds on ABC iView. Over five beautifully-filmed episodes, the program follows a social experiment that brings together elderly people in a retirement village with a group of lively 4-year-olds. It’s one of the most enchanting, life-affirming TV programs I’ve seen.

The kids and the grown-ups were equally adorable – each dyad (one older person and one 4 year old) seemed to bring-out the best in each other. It was delightful to watch. Fiona the kindergarten teacher/facilitator was incredible. She has amazing interpersonal skills. [BTW: does anyone know Fiona’s surname? – she deserves to be credited properly]

I only have one problem with the program: the way the 15-item Geriatric Depression Scale (GDS-15) was used/portrayed. It was a very good idea that there was some pre- and post-intervention testing, and it’s terrifically handy to be able to quantify the degree that people self-rate their mood. However, all the scales I’ve ever seen, including the GDS-15,  come with the disclaimer that they’re screening tools, not diagnostic tools. However, that’s not the way the GDS-15 was portrayed on this TV program.

Screenshot from approx. 47 minutes into Episode 5 showing the false dichotomy that 5 or below on GDS-15 = “not depressed” and 6 or above = “depressed”. Pfft! As if.

In the TV program the geriatricians referred to scores above 5 on the GDS as “depressed”. That’s not quite the way it works. The GDS-15 does not diagnose.

Four reasons why the GDS-15 is not a diagnostic tool:

  1. The GDS-15 asks for a “snapshot” of how the person has been feeling for the past week. As per the diagnostic frameworks used worldwide (DSM-5 and ICD-10) symptoms must be present for at least two weeks for depression to be diagnosed.
  2. The GDS-15 is a dumb screening tool. It won’t (and can’t) take social circumstances into account. Many of the symptoms of depression are also symptoms of grief/bereavement/significant recent stress. GDS-15 questions include:
    • “Have you dropped many of your activities and interests over the last week ?”
    • “Over the last week have you been in good spirits most of the time?”
    • “In the last week have you been feeling happy most of the time?”
    • “In the last week, have you preferred to stay at home, rather than going out and doing things?”
    • “In the last week have you been thinking that it is wonderful to be alive?”
      If your spouse died 10 days ago, not only would these questions be terribly insensitive, but your answers probably wouldn’t be very positive. That doesn’t mean you’re depressed. That means you loved your spouse. The GDS-15 screens for symptoms, not context.
  3. There’s more than one way to interpret the GDS-15 score. Which is the correct way? It depends who you ask:
    • As per the Royal Australian College of General Practitioners, “Although differing sensitivities and specificities have been obtained across studies, for clinical purposes a score >5 points is suggestive of depression and should warrant a follow up interview. Scores >10 are almost always depression.” [source]
    • As per an online version of the GDS-15 endorsed by the GDS-15 lead authors [source], the meaning of the scores are thus:
      0 – 4 = normal, depending on age, education, complaints
      5 – 8 = mild
      9 – 11 = moderate
      12 – 15 = severe
    •  As per the screenshot above, the geriatricians in Old People’s Home For 4 Year Olds set a cut-off line between “not depressed” and “depressed” at 5.5,
  4. The model of a dichotomy of “depressed” or “not depressed” does not reflect reality. You don’t suddenly get labelled “depressed” because you scored 6 on the GDS-15, and you aren’t suddenly deemed “not-depressed” because you scored 5 the next time you’re screened. In reality, clinically significant changes in mood tend to happen over weeks or months. Minor day-to-day fluctuations are just part of the human experience – not something to be pathologised.
    When it comes to mood, you don’t cross a line between “depressed” and “not depressed”. There is a line, but it’s a continuum. It’s a continuum that we all slide up and down. It’s just that people who experience depression travel further along the continuum than they would like.

Closing Remarks

Please don’t let my critique of the use of the Geriatric Depression Scale deter you from watching Old People’s Home For 4 Year Olds. It’s a terrific program based on a wonderful idea, which is articulated further on the Ageless Play website [here].

Something I do in my paid job and as part of my [unpaid] social media portfolio, is to challenge the myths and misunderstandings that happen around mental health matters. As I’ve argued previously [here], all I’m doing in this blog post is articulating my argument why we should resist the temptation to interpret screening tools as diagnostic tools.

End

That’s it. As always, feedback is welcome via the comments section below.

Paul McNamara, 26 September 2019

Short URL: meta4RN.com/scale

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s