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Why the stress research doesn't stack up (part 3/3)

A close shave

In 2020 I started noticing patches of hair loss on my head. Within the space of 6 months, I’d lost 60% of the hair on my head, most of the hair on my face, all of my arm hair, stomach hair, and even nostril hair, although just in one side strangely.

The first question I was asked when discussing it with anybody was, “are you stressed?” or telling me “You must be stressed”, and “I know stress can make your hair fall out”.

Its obviously covid-stress!

Now although 2020 was the year of Covid-19 and lockdowns, and a terrible year for many, from a personal perspective I was one of the lucky ones. I kept myself healthy, occupied and enjoyed improving my skills with technology, something I’d always avoided in the past. And business was good too, so to say 2020 was in any way stressful for me would be a lie.

The facts don’t lie

Having been involved in mental health for a number of years, and also being involved in the world of stress (not itself a psychiatric label) I knew what the research said, “stress makes you ill”. It also causes stomach ulcers, and a whole host of other things such as hair loss or alopecia.

This prompted me to take a deep dive into the scientific literature and explore the research into stress and alopecia. I knew I was going to find solid evidence, as it’s there in black and white on every charity homepage and every article you read about alopecia, “can be caused by stress”.

Not what I was expecting at all

As I delved deeper and deeper into the research, I came across a gaping flaw that I’ve since found out besets most research claiming to show a link between stress and health conditions. It’s what we call ‘observational studies’ (the case control variety).

You’ve probably comes across them before. For example, “People who eat olive oil live longer”, “June 12th is the happiest day of the year”, “people who drink moderately live longer than those who are tee-total”. These are the tabloids favourite as it gives them a great headline to shout about.

The type of studies mentioned above fail to take into account other possibilities, such as people who use olive oil may also follow other health practices that lead to longevity, or that tee-totallers may be that way due to underlying health conditions that affect how long they live. The point is these studies simply point to a ‘possible’ link; but they do not prove one. And nor do they claim to, its those interpreting them incorrectly that do.

Not designed to prove causation

Case control studies are essentially a form of observational study used to look for potential causes, where you find a group of people with a health condition (eg: alopecia, or cancer, or stomach ulcers) and data are collected either by going back through these people’s medical records, or by asking them to recall their past history to identify possible cause/s for their condition. Possible links may arise, and further research goes in that direction.

Word from a pro

According to Trisha Greenhalgh, a professor of primary healthcare, and a practising GP, “They (case control studies) lie lower down the hierarchy of evidence”. Professor Greenhalgh, who also wrote a renowned book on how to interpret scientific research papers, adds, “in addition, such a design cannot demonstrate causality – in other words, the association of A with B in a case-control study does not prove that A caused B”.

Animals, observational studies, and self-report data

As if basing human ideas on studies of animals under torture, and using observational studies to imply a causation isn’t shaky enough ground, many of these studies into the hair loss and stress connection are based on self-report data. That same self-report data that relies on your recollection of events and assumes they’re accurate.

Now where did I put my shades? Oh yes, on my head!

Countless studies I read on the links between alopecia and stress were based on people’s evaluation of how stressed they say they were when they began losing their hair. Stress in many cases in these studies being defined as anything ranging from loss of a job to moving house, leaving it almost impossible for somebody not to recollect experiencing some of those life events being lumped under the banner of stress.

Self-report data in notoriously unreliable, as human memory is not perfect. As author of the bestseller on stress Professor Robert Sapolsky says in his book, “it is not clear whether humans are really exposed to the stressors to which they claim they’re exposed”. He also adds in his book that “most studies in the field (stress) are retrospective”.

So, things aren’t as clear cut as they seem

So, most research in the stress field is based on either, animals under torture conditions, observational data (which can’t prove causality) and self-report data. All factors that reduce the reliability of the data.

Where do we go from here?

So why are we so convinced that stress causes all of these health conditions? How about inside your organisation, do you have employees fearing pressure because they believe it will make them ill? Avoiding any hint of pressure as they ‘know’ the impact it could have on their health or any pre-existing conditions?

To put this to rest we need to do what has almost never been done before, we need prospective studies rather than retrospective ones. Studies that find people exposed to stress and follow them over years to find out if they get stomach ulcers, alopecia, and other health conditions at a higher rate than those not stressed.

But this would be expensive and lengthy, which is why it doesn’t happen. The other alternative is to do what was done in many animal studies, and induce a disease in people, expose them to what they’re calling ‘stress’ and measure how the disease progresses under lab conditions. But that’s clearly unethical, although strangely ethical when it comes to animals?

Smacked legs for the press

Oh, and the news media need to think carefully about how they might be planting ideas in people’s heads about stress and disease or illness. As you may have seen in your organisation, people being terrified of getting ill due to stress isn’t good for them, it isn’t good for businesses, and it isn’t good for the nation.


Jonathan Pittam

Mental Health Educator


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