05/13/2013 05:30 EDT | Updated 07/13/2013 05:12 EDT

The Evolution of Labelling Medical Conditions

The latest version of the DSM, DSM-V, will be available in the next several weeks, and we are looking forward to some important changes. When we come to the area of psychiatric medicine, sometimes the descriptive label does describe the condition fairly clearly, and sometimes not.

brain search and human...

What's in a label? When it comes to medical conditions, down through history various conditions have had labels which sometimes reflect our understanding of the underlying causes. A good example is the medical condition hyperthyroidism, which describes too much thyroid hormone in the system causing symptoms. Hypothyroidism, on the other hand, is a condition which reflects too little thyroid hormone in the body. Essential hypertension is another medical condition that we all recognize, but in this case the descriptive label does not reflect a clear understanding of what causes it. Diabetes mellitus (sugar diabetes) again is understood by most people to reflect an abnormality in glucose metabolism.

When we come to the area of psychiatric medicine, sometimes the descriptive label does describe the condition fairly clearly, and sometimes not. Major Depressive Disorder (MDD) would be understood by most people as reflecting depression. Panic Disorder again is a pretty good description of the actual condition in terms of anxiety symptoms and what a person would experience if they suffered an actual panic attack.

When we come to Attention Deficit Hyperactivity Disorder (ADHD) the labelling is interesting. The first good clinical description of ADHD was in 1917 by Dr. Gonzalo Rodriguez-Lafora, a physician in Spain who described the symptoms of ADHD in children:

"Children that cannot sustain their attention even to hear or to understand or to respond...get distracted even by a moving fly, pinch their classmates, make fun of everything and are in constant activity."- National Library, Madrid, Spain

In North America, this condition received a label in 1930 called Minimal Brain Damage, and this was changed later in 1960 to Minimal Brain Dysfunction.

The Diagnostic and Statistical Manual of Mental Disorders (DSM) is a published summary by the American Psychiatric Association of all psychiatric conditions including ADHD. In Europe, there is a different classificatory system.

According to the DSM-II, ADHD was labelled Hyperkinetic Reaction of Childhood in 1968, and in 1980 this label was changed to Attention Deficit Disorder + or - Hyperactivity (DSM-III). In 1987, this again was changed to Attention Deficit Hyperactivity Disorder (DSM-III-R), and the current DSM-IV-TR version describes this condition as Attention Deficit Hyperactivity Disorder.

Why is this relevant? The latest version of the DSM, DSM-V, will be available in the next several weeks, and we are looking forward to some important changes. Previous renditions of ADHD in the DSM haven't been based in validated diagnostic criteria, especially for adults. The age of onset of ADHD has been debated and the DSM-V may well raise the age of onset for this important condition from seven to 12.

Another important DSM change would be the clear description and recognition of Adult ADHD, validating its existence. Previous DSMs have only made fleeting references to it.

If we look more closely at the current label, ADHD (and this is not likely to change in the DSM-V), there still remain several issues specifically as it relates to how symptoms change across the timeline. Firstly, the label Attention Deficit Hyperactivity Disorder does not subsume one of the most important and core symptoms of ADHD, and that is impulsivity. Many people who would recognize hyperthyroidism or depressive disorder in others could be quite confused by what ADHD actually looks like in adults. A reason for this confusion is that much of the childhood hyperactivity (if it was present) does decline over time, but what can persist into later adolescence and early adulthood would be symptoms of distractibility (inattention) and impulsivity. Many people refer to Adult ADHD as "ADD" (minus the hyperactivity).

The point I am trying to make is that labelling any medical condition will always have its attendant challenges and fair share of criticism because of the very process of labelling. Against this, if we don't have a clinical description and a label of what it is, then our cooperative efforts in terms of studying this condition will be less effective. We need some kind of common parlance so that people can communicate back and forth in terms our current understanding of ADHD.

In the original depiction by Dr. Gonzalo Rodriguez-Lafora, he published his description of these children in a book, Los Ninos Mentalmente Anormales, so even he resorted to a rough description of children with this condition.

Finally, the label ADHD presupposes that this condition is similar in females and males, and this is far from the truth. In fact, most of the research which has been done on ADHD has been done in studies focussing on Caucasian boys. The biggest study of children with ADHD, the MTA Study, focussed on males and only 20 per cent of the children in the study were female. In addition, most of the treatment studies have again focussed on little boys. And so as our scientific understanding of what ADHD looks like in females develops, certainly this will be included in later versions of the DSM.

All of this leads to lively debate and forces scientists and clinicians alike to better fine tune an evidence-based, clinically relevant description of Adult ADHD.

Photo gallery Children's Health Stories Of 2012 See Gallery