Diagnosis 'uncertain': a follow-up study.

During a ten year study, 10% of patients at a general hospital in-patient unit had unsolved diagnostic problems at the time of discharge from hospital. These 132 cases were designated 'uncertain' and were followed up. Eighty-three patients were ultimately diagnosed, and 300 consecutive in-patients discharged from the same unit with a definite diagnosis were also studied. The clinical features and diagnoses of the two groups were compared. Special features associated with uncertainty were: a presenting complaint of pain; apathy without apparent mental or physical cause; hallucinosis or major paranoid symptoms without other good evidence of psychosis. Age was found to be relevant; compared with patients receiving confident diagnoses, those with uncertain diagnosis due to depressive psychosis were more often younger, while those due to neurosis or personality disorder tended to be older. Atypical psychotic depression was the condition most commonly associated with diagnostic doubt.