The dirty secret about that bogus statistic that trans bigots always neglect to share is that the number comes from people who are forced to suppress or deny their TG issues.
Once they are allowed to transition openly and without social stigma the numbers normalize.
In other words, it isn't because they are TG, it's because of the way they are treated because they are TG.
Ubiquitous hate and scorn can contribute quite a bit to depression in someone who is already struggling with a thorny medical issue.