"mothers who are channelling spirits in order to drive out the evil ancestors plaguing her daughter (who, unsurprisingly perhaps, has mental health issues)" As you illustrate here, the trouble isn't just the person with beliefs/delusions, but the effect on the health of those they come into contact with. Here's my one: as a teenager, I was raped. One day less than six months later, I was out with my mum and a couple who were "friends of a friend" of hers, when I saw my rapist walk past. I had a panic attack and then fainted. The couple insisted I must be possessed and offered to arrange an exorcism. To shut them up, mum gave the very brief explanation I've just given above. This only made them more excited - they then decided I must be under evil influences to have "led on" the boy to have done such a thing, and should see their priest as a matter of urgency... Mum decided that "respecting their culture" was secondary to protecting her mentally vulnerable daughter from being seriously affected by having to hear any more of that rubbish.