Categorising things is something that scientists have a tendency to do. Earth Scientists are prime examples of this, with all rocks (on Earth) fitting into three main categories: igneous, sedimentary and metamorphic.
And this is just the tip of the iceberg. Let’s not even get started with the discipline of palaeontology (dinosaurs) or petrography (minerals)! However, in other disciplines categorising is not so clear cut, and often it’s the one thing that they are trying very hard to break away from.
One such discipline is psychiatry, where the latest edition of the “Bible of the psychiatric field”*, is causing some controversy for its continued use of discrete categories of mental illness diagnosis. The Diagnostic and Statistical Manual of Mental Disorders (DSM) is the clinical reference for mental illness and provides a checklist for the diagnosis of patients all over the world. The most recent edition, DSM 5, was published on the 18th May 2013 and continues to frustrate researchers and clinicians by sticking with the discrete categorisation of the major mental illnesses including schizophrenia, bi-polar disorder and depression.
In comparison to other sciences, psychiatry is a relatively young field, emerging in the 1900’s when Freud was named as psychiatry’s father. The consolidation of these categories of mental illness was adopted in the 1980’s, based on Emil Kraepelin’s concept that different illnesses presented a unique set of symptoms and therefore are assumed to have unique causes.* The evidence available to these great scientists and their peers was mostly based on symptoms that patients presented with, and by following in the footsteps of many empirical scientist before them, they searched for patterns within the data.
But is this the best approach? The mind is very complex and even though there has been an increase in neurological research into mental illness, generally the subject area still remains a mystery. Black-and-white diagnoses can cause confusion for doctors and patients alike. For example, the director of the Stanley Center for Psychiatric Research, Steve Hyman, found that as patients symptoms wax and wane over time, they receive different diagnoses, which can be upsetting and give false hope*. “The problem is that the DSM has been launched into under-researched waters, and this has been accepted in an unquestioning way”, he says*. An alternative approach is one that treats the illnesses as a continual overlapping spectrum, referred to as a dimensional spectrum.
Researchers are finding more and more overlapping symptoms, such as mood or cognitive impairment, displayed in patients with different illnesses and this could lead to the patient being diagnosed with several disorders. By assessing the severity of the different symptoms along this scale it may help to diagnose more complex problems. Obviously, this is a simplified approach but more work is being done to improve this spectrum approach, instead of the discrete unlinked categories.
So, is there room in Earth Sciences for such radical thinking when it comes to categorising our data? Surely everything is on a spectrum? As I ponder this, I will continue to search for some discrete patterns in my geochemistry spreadsheets.
Click here for more information about mental illness.
*Taken from the Nature News Feature