Background. Despite more than 100 years of study, there remains no definitive diagnostic
validation of the functional psychoses. Factor analysis suggests the presence of three or more
psychopathological syndromes in functional psychoses as a whole. The relationship between these
factors and cerebral anatomy has been investigated in schizophrenia only. This study aimed to
address the relationship of symptom factors to clinically important variables and cerebral anatomy
in a sample of psychotic patients with a spread of diagnoses.
Methods. In a sample of patients with functional psychoses, symptom data was obtained on four
consecutive admissions using the OPCRIT symptom checklist. OPCRIT data was used to generate
operational diagnoses in accordance with pre-set criteria and a principle components analysis was
performed on symptom data. Factor loadings were compared between each admission to examine
factor stability over time. Factor scores at first admission were also correlated with clinical variables
obtained from patients' case notes. From the sample of 204 patients, 64 subjects were recruited and
underwent an MRI scan of the brain. Regional anatomical volumes were compared with diagnosis
and factor loadings at first admission.
Results. A principal components analysis gave a four-factor solution of ‘manic’, ‘depressive’,
‘disorganization’ and ‘reality distortion’ factors at each admission. Factors showed a high degree
of stability over the four admissions studied. The factors were significantly associated with several
clinical variables. Three of the four factors were associated with a specific pattern of cerebral
Conclusions. This study suggests that factors may correspond to relatively specific disease processes
underlying functional psychotic illness. We propose that the use of symptom factors may facilitate
the investigation of the underlying mechanisms of psychotic illness.