From Causation by Nick Youngson CC BY-SA 3.0 Alpha Stock Images

“If you ask the wrong question, the answers don’t matter” — anonymous

It’s an old saw in science that “correlation is not causation.” It’s more than an old saw; it’s an absolute necessity for clear thinking. Just because we see two things correlated with each other doesn’t mean we know what causes what. A very respected colleague reminded me the other day of how easy it is to have assumptions interfere with that clear thinking.

This colleague pointed out that people with mental health diagnoses die, on average, 18 years earlier than people without mental illness. The pitch was that we should work to decrease stigma so more people with mental illness can get appropriate healthcare. I agree we should get rid of stigma. It has no place in health care. In fact, this is not the kind of thing anyone would disagree with, but it got me wondering. Would it help?

My colleague was basically saying that A (the stigma against mental illness) causes B (increased mortality in those with mental illness). He was also saying that A causes B mediated through C (stigma causes poor healthcare) and D (poorer healthcare causes increased mortality). Pretty straight forward logic:

The thing about logic is that if you don’t watch your assumptions, the logic will lead you to the wrong place. It isn’t the logic that’s at fault in such a situation. It’s the assumptions. So let’s check our assumptions.

Since the person has to be alive to have mental illness, then it is early death that comes after mental illness. This sets us up for the assumption that the first thing that happens has to be the cause. This temporal order is what sets up the assumption we default to. We then conflate the two things throwing stigma in with mental illness and physical health concerns in with early death.

So, we assume that A (mental illness, stigma, poor mental health Tx, etc) causes B (early death, physical morbidity, etc). Yet, couldn’t poor health cause mental illness through the stress of having physical illness, poor medical Tx, and lack of medical care? Admittedly general medical care isn’t as bad as mental health care, but for many it’s still poor.

Or better yet, couldn’t A and B be correlated by having the same cause? For instance stress imposed via social problems such as systemic inflation, increasing cortisol and causing both increased psych symptoms and physical morbidity. Or mutation of an gene involved in cellular energy regulation would affect all cells would cause morbidity in both brain and somatic systems.

Finally, the most likely association is that all of these associations are operative and our model shouldn’t be the straight cause/effect one we were taught. Rather there is a web of interactions that all need to be addressed, because these groups are not homogeneous.

Some people with mental illness do have physical morbidity because stigma leaves them with less than adequate healthcare. Others have mental illness because of the stress of their physical problems. Still others have both problems because in born errors of metabolism or environmental stresses. There are many more subpopulations we can name.

Every time I raise this point with academics they say it’s too hard to do research other than the way it’s done. Yes, the right way is hard. But it would yield actual solutions rather than vague generalizations that get over politicized and don’t end up helping anyone.

H. L. Mencken said, “”For every complex problem there is an answer that is clear, simple, and wrong.” Shouldn’t we stop looking for the easy blame and get down to the real answer? Yes, we should, even if it’s hard.


Howard Wetsman is an addiction psychiatrist and founder of GenEd Systems. He maintains a channel on YouTube where he has released his serial Ending Addiction. If you want to know more about genetics, check out GenEd Systems and learn along with them as they grow.

Addictionologist educating the world soon at Solves problems with TOC. Author of Questions and Answers on Addiction. Twitter: @addictiondocMD

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