Functional Impairment and Waiting to Fail
I see a similar problem in the requirement of 'functional impairment' for diagnosing psychiatric disorders. Almost every condition in the DSM-IV has a criteria that looks something like the following:
"The disturbance causes clinically significant impairments in social, occupational, or other important areas of functioning."
The phrasing differs (the above was taken from the DSM-IV criteria for Asperger Syndrome) but what this means is that you can have all the characteristics of a specific condition, but if it's not currently interfering with your everyday functioning, you can't be diagnosed with the condition.
An example of how this works in practice can be given from Baron-Cohen et al (2001), in their discussion of the factor analysis and validity of the newly-designed Autism Spectrum Quotient:
"To validate the AQ in Group 3, we called in for clinical interview all subjects scoring 32+, of whom 11 agreed to be in-terviewed. Using DSM-IV criteria for autistic disorder, an experienced clinician (S.B-C.) sought to establish the number of criteria each subject met. The clinician remained blind to the AQ score of the subject being in-terviewed. Of the 11 subjects scoring 32+, 7 met cri-teria for HFA or AS. No diagnoses were actually made for two reasons: No parent was present to provide independent developmental data, and because none of those meeting criteria complained of any current unhappiness. Indeed, many of them reported that within a University setting their desire not to be sociable, together with their desire to pursue their narrow or repetitive interests (typically mathematics and computing) was not considered odd, and was even valued. Of the other 4, all met at least three criteria. In all 11 cases, however, there was evidence from self-report of significant impairment in functioning during the school years (social isolation, being bullied, and difficulty in making friendships)."
Seven of those 11 could have been diagnosed with either autism or Asperger Syndrome, and the remaining four with PDD NOS, if it weren't for the fact that, in a university setting, they experienced no significant impairment. But what about when they graduate? How will their autistic style of socializing come across in a job interview? If they get the job, how well will they navigate office politics? If required to deal with the public, how well will they handle the unwritten rules of providing good service?
I'm not the only one to raise these concerns. For example, Hurlbutt and Chalmers (2004) interviewed six adults with Asperger Syndrome (four of whom were university graduates) about employment and found that all six experienced significant difficulties. The four with university degrees had not managed to find work in the areas they were trained in, but instead took what they could get, which were often low-paying, menial jobs. All six emphasized that the biggest challenges in the workplace were social in nature - the work itself they could do easily, but they tended to misunderstand and be misunderstood by their bosses and coworkers. Some also had issues with sensory processing and changes in routines. For example, one participant said:
"I have a degree in political science and am just trying to get a decent job with decent pay and benefits. I have cleaned cat cages, done janitorial work (which is boring, bor-ing, boring), office work at the VA, [been] a telemarketer (which I hated, but I learned how to do public speaking!), and worked in a group home on the early morning shift."
Imagine a university student with the characteristics of Asperger Syndrome. In school, he was bullied and excluded, but back then no one knew that an autistic person could be verbal with no glaring delays in self-care skills. Now, he's respected and seen as very intelligent, and although he has few friends, he's doing quite well. If his Asperger Syndrome remains undiagnosed, he'll eventually graduate with the thought of working in the field that he's trained in, only to find that getting and keeping a job requires an entirely different set of skills, skills in which his weaknesses show quite clearly. He could get a diagnosis at that point, but late twenties and early thirties is pretty late to be learning social skills.
Whereas, if he was diagnosed in university, he could spend his university years learning, in addition to the skills needed for his degree, the social and organizational skills needed to get and keep a job once he graduates. This intervention could spare him a great deal of misery once he gets his diploma and heads out to find work. Furthermore, society could get the benefit of his skills.
Many disabilities, like high functioning autism and ADHD, are identified mainly because they cause problems in school. But some people who aren't identified at that age go on to find niches where their disabilities don't cause any impairment. The problem is, things change. What doesn't cause impairment in one setting could easily cause impairment later on in another setting.
Now, there is a reason for the functional impairment requirement. The idea is, you get a diagnosis in order to receive appropriate treatment. If you don't need that treatment, what point is there to diagnosis? Well, besides the fact that diagnosis can serve other purposes besides getting treatment (self-understanding, identification for research purposes, etc), it's quite possible that someone who shows no impairment now will show impairment in the future. In fact, meeting criteria without impairment now could mark someone who is quite likely to be impaired at a certain point in the future, just like poor reading comprehension in a third grader marks a kid who almost certainly will fall behind in the next few years if he or she isn't helped now.