@SunCloudRain Do you mean mental health condition (e.g. depression) or mental disorder (e.g. autism)?
You raise a good point about transitioning not completely alleviating distress (at least not completely), but I would say it is able to reduce dysphoria in some cases where therapy is unable to help. Your own cases sheds light on exactly why the first resort can't be transitioning though! I'm glad to hear it turned out well in the end.
@Homemerge How is it only a mental health condition? For those who have gender dysphoria (or what appears to be gender dysphoria) in connection to their sexuality, sexual interests, or neurodiversity, I understand your meaning, although I'm still not certain 'mental health' applies. However, our brains do have a sex that they conceive of us as being (a sort of gender identity I guess) and dysphoria can result from any discrepancy between this conception and genuine sex. The David Reimer case demonstrates this perfectly. Reimer was brought up a girl and told he was female despite being male. The resultant dysphoria caused him to (de)transition by the time he was 15 years old, having had discomfort 'always' and being suicidal when he was 13. Here the brain knew it was male, but was being told the body was female. Parallels are clear with transgender experiences--the brain thinking it is one thing, but the body being another.
@WallaceinAnderland Eddie Izzard is a difficult case. He has said he felt transgender since the age of 4, but then again, he has identified as genderfluid and was OK with being referred to as a man (at least at some times) in 2019. This lack of permanent and unchangeable dysphoria suggests to me that any dysphoria he think he does have is born out of something entirely. In other words, his feelings could be treated with therapy.
By people who claim they have no sex at all, are you referring to agender or non-binary people? Again, I think they fall into the therapy category. It's not a coincidence that the number of people identifying as agender or non-binary has risen massively with awareness and 'trendiness' of the trans movement along with rates of neurodiversity. 'A lifestyle choice' still feels like a misnomer there though; as much as it might be for something like depression. They do genuinely hold feelings about their gender, but there's actually no neurological disorder. Your examples of badly treated young women and older men do seem like lifestyle choices though, where a conscious decision for some sort of ulterior motive.
@BinturongsSmellOfPopcorn It means I think that other people should treat these transgender people like they would anyone else of that gender, referring to them as they prefer and allowing them into spaces for that gender. But I wouldn't support any government attempts to force people to use certain names or pronouns, nor would I support the government forcing private businesses to operate mixed-sex facilities in this way. I still think school facilities and prisons should be separate.
Distinguishing the cause of dysphoria is complex but I think age is a key factor. In the David Reimer case I mention above, Reimer said he had always felt some level of dysphoria. This matches cases of gender dysphoria seen before roughly 2010. The typical patient referred to gender services was in their infancy, usually male too. By comparison, non-neurological causes manifest in dysphoria that starts later in life, around puberty or even in adolescence. So too do the ways of transitioning change: someone with this neurological mismatch will often want to go the whole way with every possible method of transition, but today we seen more and more people saying they are non-binary or genderfluid or not taking surgical options.
Dysphoria may not be solved by transition, but it can be reduced by it. A reduction in dysphoria doesn't require it to be fully eliminated. I'm aware mental health worsens etc., but I think this would be seen regardless of the treatment or whether there is treatment at all (at least for those whose gender dysphoria can't be treated with therapy). The Finnish and Swedish studies compare rates among trans people with controls, but not just the rates of trans people before and after transitioning. When this has been done in the past, e.g. with Smith et al. (2005), transitioning seems effective.
Neurological gender dysphoria is different from weight-related eating disorders and body dysmorphia because the problems there are of self-image and anxiety. They have no connection to what is genuinely true about the patient and can't be alleviated with acceptance or validation. Gender dysphoria, however, is based explicitly on the fact that the patient really is one sex or the other, and not the one their brain thinks of them as. There's evidence to suggest that transitioning does help in these cases too.
@Shortshriftandlethal Gender dysphoria itself is not a recent phenomenon like queer theory. It may appear recent because the trans rights movement has gained a lot of ground in the last decade, and there has been a huge increase in the number of those diagnosed with it, but gender dysphoria has been investigated alongside transitioning for decades, at the very least since the 1960s.
The genders themselves and their roles are socially defined, but a person's gender isn't. A feminine gay man is still a man even if he's soft-spoken and wears dresses; a masculine lesbian is still a woman even if she's brash and wears suits. I would argue a person's gender is what their brain conceives of their sex as being. Nevertheless, I agree with you that 'gender ideology' does mistake gender non-conformity with being transgender, and that this argument has led to the increase in people whose gender dysphoria (if it can be described as that) can be solved with therapy.