CBT and psychosis is a very contentious area of psychiatry. A leading supporter of it is Peter Kinderman. A leading sceptic about it is Keith Laws.
Severe sz cannot be treated with CBT so it depends on severity. Severe szics are out of reality and won’t cooperate with a psychologist. I am still like that even with meds.
That’s a point that’s been raised by those who are sceptical about the benefits of CBT for psychosis . That those at the milder end of psychosis tend to be used in such studies.