It is a diagnosis based on subjective conclusions and seems to be the diagnosis of the decade.

I agree that it seems to be the diagnosis of the decade, especially by (well meaning) teachers and family practice doctors whose area of expertise is not ADD/ADHD.

However, your first statement about it being based on subjective conclusions sounded pretty dismissive. ALL diagnoses of the mind are based on subjective conclusions (except for ones so serious that it will show up on an MRI, qEEG, or SPECT scan; and even then the analysis can still be called subjective).

A team of leading experts, in conjunction with the World Health Organization, developed the Adult Self-Report Scale (ASRS), and about 80% of the people who score positive on that test turn out to have ADD when a full evaluation is done.

From what I've read and the doctors I've talked to, the medical community is changing their perception of ADD from a "disorder", to just a different type of mind (which undiagnosed tends to create a lot of problems in modern society). There are a lot of different opinions and myths (and stigmas) about ADD in popular culture right now, and just dismissing it as an over-used catch-all diagnosis keeps a lot of people from looking into it closer; some of whom could really have a huge difference made for their lives if it was properly diagnosed and treated.

edit: this interview with Howie Mandell is great.

*"I think the biggest issue in adults is that they don’t think ADHD is real when you think about it in just the layman’s way, you think of a hyper kid running around..." *

"What we are trying to do is create awareness that ADHD is real for adults. I think some people just use it for vernacular sometimes -– I can’t do that, I’m ADD or ADHD -– and it really is an issue and it is real."