I might be frustrated with people who self-diagnose, too, but considering I didn't get that diagnosis until later in my teens myself, I have sympathy for folk who are going through 'what the fuck is even wrong with me maybe it's this' and can't get it figured out by an actual psychiatrist for whatever reason. I've been through that, tests clearly showing something's wrong, just not what.
On a tangent to that subject, I have been undergoing psychotherapy since I was 4. When I was 2, I had a seizure, and the doctors discovered that I basically had a convulsive focus in my brain. I basically had to take some aggressive as shit medication or have seizures. Said medication had (and still kinda has, but no one uses it anymore) a reputation at the time for stunting mental growth. Basically, other people thought that those who took it would grow up to be mentally retarded. (It affected my motor skills, but I eventually overcame that.) Then, when I hit puberty, bam, it came back and I had to take medicine again, until I was about 14.
I think I consulted with maybe fifteen different psychiatrists before I found my current one. I was tentatively diagnosed with ADHD, depression, MAYBE bipolar disorder, Peter Pan syndrome and schizophrenia (that one was definitely a fucking barrel of laughs, let me tell you guys that much. Only not). Not knowing WHAT is wrong for sure and trying to treat the symptoms can have some massively awful consequences. I MIGHT have been a bit better off if I had admitted that something COULD be wrong with me when I was younger, but eh. I didn't really have the maturity for it.
Back on topic though, at least the solution in English is simple. You guys have a gender-neutral third-person pronoun that you can use on the singular. We're not that lucky, because we pluralize he/she individually instead of using 'they'.