In general, "loss of contact with reality" is well understood to be an individual experience. If you think voices are talking to you, that's schizophrenia. If you think God wrote an entire book of life advice, that's Christianity. So, kinda by definition, a large group of people cannot generally experience "loss of contact with reality", they're merely mistaken.

The alternative is to accept that 90% of humans are suffering some form or another of psychosis, because there's very little that even a majority (51%) of people agree on, and that means about half the population is wrong about any given topic. Multiply by the number of topics out there...