The Northwick Park 'Functional' Psychosis Study. Phase 2: maintenance treatment

This study blindly compared the value as a prophylaxis against relapse over a period of up to 6 years, of pimozide, lithium, pimozide+lithium and placebo of 30 patients with functional psychotic illness who had achieved satisfactory recovery on the same medications during an acute episode of illness. Pimozide was significantly more effective than placebo pimozide in preventing relapse (p=0.01). No significant effect for lithium was found. There was a significant deterioration in positive symptoms (p < 0.05) as relapse approached, but otherwise features of impending relapse were not detected. It is concluded that prophylactic neuroleptic medication is of value even in patients who have recovered from an acute episode of psychosis without active neuroleptics. Such an acute response does not identify a group of patients who can be predicted to do well without continued medication.