Two mood tests compared: initial findings

Every day I count my blessings at having such brilliant readers.

You may recall that a couple of days ago I asked for help with a survey that asked you to complete two different measures of mood.

One was the test I’m using in the Nudge Your Way to Happiness book (getting closer and closer to completion by the way, and shaping up even better than I could have hoped).

The other was a test called the PHQ-9, often used by doctors as part of the process in diagnosing depression.


I was keen to see how the results compared, even though my test is a “how are you feeling right now” thing, while the PHQ-9 asks you to look back over the past two weeks.

You and I both know, I’m sure, that it’s possible to feel temporarily OK in the moment while having been at a low ebb for some time overall.

Alternatively someone can have been great overall, but might feel momentarily low because of some or other temporary nastiness.

One reason for my interest is that an influential health task force here in the USA has just recommended that every American adult should be screened for depression, and one of the tools they’re considering is the above-mentioned PHQ-9.

A concern I have is that some of the PHQ-9’s questions are pretty heavy (e.g. How often have you had thoughts that you would be better off dead or of hurting yourself in some way?).

Screening people for depression means doing so on a repeated basis.

You can’t just do it once.

But if you regularly ask people weighty questions such as these, how do you know that this in itself won’t contribute to people feeling bad?

It wasn’t just me thinking that.

Here’s what some readers said:

“Wow the second one is terrible! What an awful way to get insight into your mind!” — Georgia

“Woah! The first part made me feel good about myself… after completing the second part I feel like I’ve been miserable for the past 2 weeks! Being in a positive frame of mind, I recognise this isn’t true – but if I was feeling negative, life wouldn’t feel rosy!” — Fion

“I see what you mean about possibly feeling worse after the official one! It almost puts thoughts of doom and gloom into my head. :/” — Manymules

Sharon is a therapist, and says, “You make an excellent point about the potential of feeling somewhat worse after taking one of the “official” depression screening measures. I find the PHQ-9 quite “clunky” for many clients and instead use your WellBee cards (essentially what your Nudge well-being test is) during our weekly check ins.”

Lesley, another reader, stressed the importance of wording. She said, “I took out a funeral plan a few years ago and arranged monthly payments. Each month on my bank statement there was an item ‘FUNERAL PLAN’ £250. I couldn’t stand reading this each month so phoned them up and paid the whole lot in full so I don’t have to see it.”

Of course it will take time to properly analyse the responses we got, but I couldn’t resist quickly running some stats, and here are the preliminary findings:

* There’s a reasonably strong negative correlation (-0.72) between the Nudge test and the PHQ-9. It’s negative because high scores on the Nudge test indicate higher levels of well-being, while a high PHQ-9 score means the opposite – it’s measuring depression rather than “happiness”.

* Getting a low score on the Nudge test (over a period of time) could therefore be an indicator of depression.

* Quite a few Moodnudges readers seem to be battling depression. The survey was anonymous of course, so we don’t know who is and who isn’t, but more than a third of responses were from people who have the symptoms of at least Minor Depression. 11.5% of the total could be identified as “Major Depression, moderately severe”, and a further 5.8% were categorised as “Major Depression, severe”.

If you felt your scores put you into any of the Minor or Major categories, it may be a good idea to speak to your doctor if you haven’t already done so. There are versions of the PHQ-9 with scoring tables online, if you’d like to explore it. Here’s one, for instance:

My guess is that someone taking the Nudge test every day would probably get scores that were a fairly good proxy for the PHQ-9, making it a potentially more palatable way of screening for depression.

For now, though, let’s get this book out and see what we learn.

One thought on “Two mood tests compared: initial findings

  1. Jon – you get the readers you derserve! Doing a brilliant job = brilliant readers who are loyal and who value you highly. I don’t know you but feel a strong personal connection, so if you’re pleased with responses, don’t forget to give yourself a pat on the back. We wouldn’t do it if we didn’t care.

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