CHARACTERISTICS OF EARLY-DIAGNOSED AND LATE-DIAGNOSED SCHIZOPHRENIA -IMPLICATIONS FOR FIRST-EPISODE STUDIES

First-episode studies of schizophrenia are being carried out in many p laces. However, previous work has suggested that only half of the pati ents with schizophrenia receive the diagnosis in the initial stages of the illness. We examined whether cases of early- and late-diagnosed s chizophrenia differed with respect to key sociodemographic characteris tics and indicators of service use that might bias first-episode studi es. Individuals who (i) presented for the first time between 1983 and 1993 to psychiatric services in a defined urban area with a cumulative mental health case register; and (ii) received a diagnosis of schizop hrenia at least once during their mental health career were identified (n = 186), This sample was divided into those who received the diagno sis of schizophrenia for the first time within the first year of servi ce contact (early-diagnosed schizophrenia; EDS), and those who receive d it for the first time after the first year of service contact (late- diagnosed schizophrenia; LDS). The 10-year incidence of EDS and LDS we re 10.4 and 7.0 per 100 000 person-years, respectively. EDS and LDS di d not differ in their pattern of association with sex, single marital status and higher levels of neighbourhood socioeconomic deprivation, H owever, EDS was more incident in the higher age groups, and the level of service use was higher for EDS cases in the first years of contact with mental health services, with LDS cases gradually catching up and exceeding EDS service use later in the illness course. Although differ ences between EDS and LDS were few, studies of patients with schizophr enia in the 'first' episode are likely to be most representative if pa tients who receive the diagnosis for the first time after previous epi sodes of care for non-schizophrenic episodes are also included. (C) 19 98 Elsevier Science B,V. All rights reserved.