I would also add, if not to much of a derail, that having a narc/NPD in the room is an absolute PAIN IN THE a for other members as they tend to swan in, change the entire balance and atmosphere of the meeting, suck attention, create drama, gaslight, do inappropriate things like get involved in romantic relationships with other members, gather flying monkeys, make tension, manipulate, create a huge mess and then disappear. Only to pitch up a few months later in a different room, with a different persona and a different sob story.
Did I mention PAIN IN THE a? Yeah, that.