Patients in the early stages of schizophrenia, not yet treated with antipsychotics, do not have problems with sleep continuity, but with falling asleep.
The study also shows that the fourth phase of NREM sleep (slow-wave sleep) and REM sleep are shortened in these patients.

The study was conducted on a group of 22 people (including 11 patients with schizophrenia, never before treated with antipsychotics, and 11 healthy subjects).