Okama Hakusho is a manga that explore the thematic of the narcissism though the gender bender genre. I would says that it is a "tragicomic" manga: furiously ridiculous/funny while being at the same time very terrible as you watch the MC loosing touch with reality little by little, especially in the last third of the manga.
The plot is relatively simple:
Okama, the MC, try to find the "true love" of his life, but because of a joke of his pervy best friend, he ends up working at a gay bar as a drag queen. He quickly fall in love with his queen persona: Catherine.
he encounters a girl named Miki that looks like exactly as him-as-Catherine and falls in love with her too. Here starts a very uncomfortable relationship between Miki, Okama-as-Okama and Okama-as-Catherine.
That manga probably would have been your standard "ecchi boy-dressed-as-a-girl meets girl and can't confess to her" if it wasn't for the psychological development of the MC.
The manga use a very fast-paced comedy though ecchi and a very caricatural supporting cast, yet the manga also has very heavy moments where you see the MC loosing touch with reality, either loving or hating himself.
Considering how fast-paced the manga is, the psychological development of the MC isn't done though long internal monologues, but mainly uses visual hallucinations, which I think is a good way to deals with the case of narcissism.
The ending of the manga is on par with the rest of the story: a very surprising ending, both funny and terrible.
And it concludes by an afterwords from a psychiatrist who explains the behaviors of both Okama and Miki, which is a very nice afterwords.
Though, if I loved the manga, it also has its cons. First you have to tolerate/like that kind of humor. And I think that the manga drags out in its middle. Otherwise, it is definitely a very good gender bender manga in my book.