One annoying trend within the entire medical community is the tendency to behave as if putting a label on a set of undesirable symptoms means that you have figured out what causes them.
This is particularly true in cases where the symptoms are behavioral–e.g., alcohol abuse, temper tantrums, talking to invisible people while walking in mid-lane during rush hour, inattentiveness in class, thinking the government is broadcasting their agenda directly into your brain via lunar antennas, thinking you are the second coming of christ, etc., etc.–so the psychiatric system is spectacularly rife with it (its diagnostic category system consists of nothing else). But the problem lies not just the psychiatric system.
Furthermore, patients and the general public are major participants in this “turn the adjectives into nouns and maybe they’ll go away” diagnostic magic trick, so it isn’t even just the medical establishment.
Let’s say I’m sneezing a lot, that I have congestion, I’ve been running an intermittent fever in the 101° range, my throat hurts like hell and I can hardly swallow, I’ve been coughing hard but unproductively, and I feel like I’ve been run over by a Mack truck. We could call that Upper Respiratory Syndrome, because that’s shorter than reciting the list of symptoms and because that way, if you have 6 out of those 7 plus one that I don’t have (bone-shaking chills, let’s say), we can say it’s the same thing.
But that doesn’t explain why I have congestion, fever, cough, a throat that feels like someone went over it with a rat-tail file, and so forth. These things are not happening because I have Upper Respiratory Syndrome. These things are happening because a population of influenza viruses has taken up residence in my mucous membranes and the little bastards are destroying cells and releasing toxins. Upper Respiratory Syndrome is just shorthand for the symptoms. That shorthand is useful in epidemiology and elsewhere and I have no objection to its use, but an explanation it most certainly is not.
I’ll even give credit where it is due: the older tendency was to slap a name on a set of symptoms that went much farther in implying that it was a disease that we comprehended. Long before we knew about the influenze virus, we had the word “influenza” to describe the symptoms, and the origin of that term was a mistaken belief that the sufferer had come under the “influence” of evil stars. Better to use terms that are more honest about our ignorance of the underlying cause, words like “syndrome” or “pattern” or “constellation”. But that advantage is lost if everyone subsequently treats the naming of the phenomenon as equivalent to understanding it anyway.
(There’s also the reverse situation where we succeed in isolating the cause of a medical phenomenon we’ve described as a syndrome, and then continue to use the “syndrome” name – AIDS for instance).
Anyway, to wrap up:
• The reason you feel lethargic and unmotivated and miserable and just want to sleep all the time is not that you have clinical depression. The things that have helped other people with clinical depression may help you (or then again they may not); and a support group composed of other people with clinical depression may be useful to you (although again, not necessarily). But when the psychiatrist said you are suffering from clinical depression, the cause of the phenomenon was not being expressed. The DSM-IV defines depression as a list of symptoms. An underlying cause has not been confirmed yet, and there may in fact be fourteen dozen different conditions or situations that can cause it, ranging from personal to biological to social to cultural.
• The reason your kid is having problems in the classroom is not that he has ADHD. You already knew he was not inclined to pay attention and was restless and could not sit still, and you didn’t regard that as an explanation. Now that someone has expressed that same observation as “ADHD”, everyone is telling you what you should do about it. They might be right, as these things have been tried on other kids exhibiting the same behaviors, or they might be wrong, as some people don’t care for the outcome and/or don’t want their kids on drugs. Either way, it’s not like your kid has been found to suffer from an enzyme deficiency that interferes with ADHD-uptake. They don’t know why the pattern occurs, or why your child specifically manifests it. It could be neurological or it could be that the teachers are boring and the classroom environment stifling for a bright kid who is rebelling or it could be that your kid is a spoiled brat who likes to disrupt things.
• The reason you are overweight, have chronic high blood pressure, have high levels of fasting insulin in your bloodstream, and do not metabolize glucose effectively is not that you have Insulin Resistance Syndrome. Everyone with those symptoms has Insulin Resistance Syndrome, that’s the definition of it, that’s what those three words mean. Yeah, it looks like serious business, as it can be a precursor condition to Type II diabetes, and yeah you are therefore a person with a medical problem. And the doctors will probably do a better job of treating it now that they’ve become more aware of how these symptoms aggregate together, and their research will improve as a result of that realization. But unless I missed the news blurb, they don’t know as of yet why it happens, and therefore they don’t know why it happened to you. Insulin Resistance Syndrome isn’t why. It is merely what.
PS – I’m over the flu 
I just used it anyway 'cuz I needed an example.