Thursday, 29 March 2012

What causes or prevents mental disorders?

There is so much confusion about what the causes of mental disorders are and what prevents mental disorders.  There is so much confusion about what the concept of “risk factors” means and  what the concept of “protective factors” means.  And for many years, some of the research in these areas has been contributing to this confusion.

One of the most commonly held confusions is that about what causes or prevents depression.  In my opinion, there is probably more nonsense written about those issues than about almost anything else pertaining to mental health and mental illness – except maybe for medications used to treat mental illness. 

Much of this confusion comes from or is related to our very simplistic models of causality – that is, our thinking about what causes what.  We often think of causality as linear – so that something that comes before the event (or diagnosis) is considered to cause that event (or diagnosis).  As we know in our frontal lobes, this kind of linear model is rare.  Mostly causality is multi-factoral and sometimes the most substantive “causal” factors are not readily apparent.  So people get lazy in their thinking and go into brain default mode – choosing to assume that what comes first causes what happens after.  This of course is using our limbic systems as explanation.  Not a good way to be less wrong most of the time.
Depression does not arise in one day.  It takes a long time between when the illness begins and a diagnosis is made.  If you (as most researchers to date have done) look at events preceding the diagnosis of depression you will get a very skewed and biased idea of what may have “caused” the depression.  As a person is getting depressed, they may create events that are due to the depression and not the other way around.  Lazy thinkers then make a completely incorrect causal inference.  They could not be more wrong!

Enter some hard thinking researchers.  They decided to investigate the link between religion and depression.  Many who did earlier cross-section studies found that depressed people went to church less often than those who were not depressed.  So what did they conclude: that being religious prevented depression!  Ouch – and this idea has been around for so long that many people thought it was true!

So here is the new lens.  It’s a prospective study (so not a cross-sectional analysis) that followed people over time led by Dr. Joanna Maselko of Duke University and published in the American Journal of Epidemiology in February 2012:

And what did they find?  They found that contrary to current mythology, religion does not prevent depression!  What they found is that as people became depressed, they stopped going to church!  Social withdrawal was a result of the depression, not the other way around. 

So, is addressing spirituality for people a waste of time?  Likely not.  Will that prevent depression – no. 

What should we learn from this information?  We need to stop thinking about causality in linear fashion and we need to start doing research that can give us answers to questions in a best evidence way – not jumping to conclusions that reinforce our biases.  Isn’t science grand?  It’s the only system that we have that is independent of our ideologies.  We need to use it more – for everything.   


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