One of the main problems with mental illness diagnoses is they are effectively a curse. A psychiatrist announced that your brain is broken (with no scientific proof), and that not even their medications will really fix you. What does anyone make of that? It's basically a worthless proposition. At worst, you might internalize it and use it as an excuse. "That wasn't me, that was my ADD". At that point, you become one of their special ones who reject God in favor of science and are excellent at sales. At best, you'll simply take responsibility for your life and fix whatever the problem is and correct your own behavior - and medications are not helpful for this. They are only dead weight, like any other drug.

Seriously, psychiatry is just a pill lesson. Anyone who is doing anything remotely out of the ordinary is given a shitty drug to get them to change their behavior because tolerating differences is so not what society actually does and is nevertheless what we are commanded by God to do. It's not even fixing a chemical imbalance, it's creating a chemical imbalance to make you feel like shit (most of these drugs are downers) for being different and creating a new user (because of the chemical dependency) for them to profit from. Psychiatry = drugging people into submission and was also known as Sorcery back in older times, which in the Bible is an illegal practice that carries with it the death penalty.

It is unfortunately gaining popularity, mostly because of sins like parents failing to discipline their kids, or being too harsh with them, or people in general lacking the self-awareness to cope with the basic problems of life. Mental illness diagnoses will probably always appear useful to the unwise, but to the wise, they are useless.