(Nearly) every insomniac I’ve spoken to knows multiple others
Just want to highlight a potential selection effect: If these people spontaneously tell you that they’re insomniacs, they’re the type of people who will tell other people about their insomnia, and thus get to know multiple others. There might also be silent insomniacs, who don’t tell people they’re insomniacs and don’t know any others. You’re less likely to speak with those, so it would be hard to tell how common they are.
Just want to highlight a potential selection effect: If these people spontaneously tell you that they’re insomniacs, they’re the type of people who will tell other people about their insomnia, and thus get to know multiple others. There might also be silent insomniacs, who don’t tell people they’re insomniacs and don’t know any others. You’re less likely to speak with those, so it would be hard to tell how common they are.