In a 20-year longitudinal study, it was found that after acute hospitalization, continuous psychosis was diagnosed in only 30% of patients with schizophrenia; 20% of patients showed no signs of reoccurrence of psychosis after the acute phase. The study, presented by Martin Harrow, PhD, Thomas Jobe, MD, and Linda Grossman, PhD, of the University of Illinois in Chicago, observed a group of 187 patients, following up with them 7 times over the 20-year period using standardized research instruments.
Early analysis of the data indicated that patients who were most likely to exhibit recurring psychosis included those who were vulnerable to anxiety or who had responded poorly when exposed to apprehensive situations.
The analysis also indicated that good premorbid developmental achievements, low vulnerability to anxiety, favorable early prognostic features, and better performance on key neurocognitive variables were protective factors.
Overall, the 20-year data support a view that a moderate to large percentage (more than 50%) of patients with schizophrenia go through episodic periods, often with adjustment difficulties and some impairment between episodes. The difference between schizophrenia and some other psychotic disorders is that the episodes of major symptoms for many of the patients with schizophrenia are often more severe, more frequent, more prolonged, and patients have slower recovery.