The transgender suicide rate is known to be far greater than that of the cisgender suicide rate. In the United States, it has been reported at various levels; usually, it is found that 40 to 50 percent of transgenders in the United States will attempt to commit suicide within their lifetime (eg. Thoma et al. 2019; Beech, 2019).
There are generally two camps arguing over why the transgender suicide rate is so high. The liberal camp tends to support the idea it is due to stigma, coming to the conclusion that if society were to accept transgenderism and reject cisnormativity and whatnot, transgenders would not engage in risky behaviors in general and would commit suicide at the same rate as cis people. The conservative camp, as I understand it, more broadly believes that transgenderism is a mental illness in itself and so having this illness will predispose you to negative behavior and a culture which will inevitably lead to a greater suicide rate. Some more liberal commentators may agree that it is due to cultural reasons, but not the premise that transgenderism is a mental illness.
There are many ways of testing these hypotheses. One method is simply looking across various countries and seeing if more accepting cultures have lower transgender suicide rates than non-accepting ones. This has been done for things such as gender differences in personality and STEM achievement, as well as the role of stigma in explaining the culture of homosexuals. Does looking cross-nationally show evidence for the stigma hypothesis? Doesn’t seem so.
China is an example of a culturally and politically totalitarian country, as well as one which is not very nice to groups such as homosexuals and transgenders. China, however, has one of the lowest transgender suicide attempt rates in the world. Chen et al. (2019) uses a nationally representative sample from Chinese people and shows that the suicide attempt rate of transgenders is only 16.1%. Of course, this is still fairly high. But, compare it to a somewhat accepting (but not fully) country like America and it seems quite odd. What makes it more difficult is looking at even more liberal countries than the United States. One study has reported a transgender suicide attempt rate at 32% in Sweden (Zeluf et al., 2019) which is double that of China’s.
I was unable to find a table of transgender suicide rate by country for whatever reason. Perhaps this is a meta-analysis worth doing. Regardless, it seems very odd that stigma would explain transgender suicide rates, at least based on national differences in stigma and suicide attempt rates.