It's possible for someone to have temporary gender dysphoria or this so called rapid onset version if I'm understanding it then. Gender dysphoria can't be a comorbidity according to the DSM but, functionally, it can be. I say this because if you have a different mental illness that makes you easily susceptible to dysphoric symptoms you may not need to treat a patient as though they have dysphoria. In fact that could make their mental health WORSE if it's their coping mechanism to want what others have or retreat into submissiveness or etc. as apart of a different disorder which draws them towards being feminine, even though they shouldn't be indulging those coping mechanisms.
If a narcissist for example wants to be a girl because they want the attention girls get, you should solve the NPD. Not feed their narcissistic coping mechanisms by validating false dysphoria.
All in all leave Mental Health to professionals or at least study it, don't make biased assumptions because you want your egg.
/thread.