I have a working diagnosis on Generalized Anxiety Disorder. My doctor never as a matter of principle diagnoses anyone under 27 with anything, but only has a working hypothesis until then (he claims the brain is not fully mature before then, and all sorts of developmental phenomena can be wrongly ascribed to a pathological condition). He is specialized in neuropharmacology and treatment of scizophrenia, and has a very standardized, for the lack of better word (scientific? empirical? experimental?) approach to psychiatry. Basically, he gives a prescription, and if it works, one working hypotheses gathers more support over others. He also treats Flattie.
Thus my Flattie is currently diagnosed with bipolar, since meds for regular depression just made her worse and stabilizers have changed her (our) life entirely. She is the other arm of a platonic vee.
Vanilla's had close to a dozen different diagnosis, and she's just twenty. She's suffered from major depression throughout her youth, but is now off all anti-depression meds and doing great
! We talked about how it would be really weird to have a partner with no experience of mental disorder ever. As if dating someone from another culture, with a different set of defining life experiences entirely.
I'm involved with rainbow Christianity and there's definitely a large incidence of mental disorder, mostly depression, self-harm and suicide attempts, among the crowd who frequents those events. Some people have participated in "healing ministries" for decades, all the while married monogamously to fellow believers of the opposite sex.
So yes, I think there's definitely a common link between unipolar depression and marginalized identities.