Eh, I already know that I suffer from a mental disorder, but it's easy for me to adapt after years of therapy. However, the way that every parent throws their kid on the ADD/ADHD bandwagon, I feel would tip the scales unfairly. ADD is a real disorder, yet any kid can walk into a doctor's office and say "I don't care about school" and get this affliction applied to they metaphorical psyche. But in reality, mental disorders can also be due to stress. Especially during a rough time for the country (or the world even), I wouldn't be surprised if depression arose among the masses. It happens, but is it due to a chemical imbalance, or are they depressed for a reason. It's what separates a disorder from anything else.
I don't mean to sound inconsiderate, but kids that have a hard time in school most likely are deterred because they are lazy or don't like their teacher/subject. It doesn't mean that every kid who has a hard time has a learning disorder. ADD actually prevents a child from focusing, it doesn't mean they are lazy. Also, alcohol and drug dependence? I don't consider that a mental disorder, it's an addiction. But the reason they would use those substances may be linked to depression, and that depression may be linked to a justifiable reason (being laid off, divorce, death in the family).
Also, mental health is a hard thing to hone in on. The only person that knows what's going on in one's head is that very individual. The only person that can diagnose this individual is a complete separate entity known as a psychologist/psychiatrist. It's a very biased approach in terms of what is really affecting the individual: a mental illness or life.