Accuracy of variables describing ethnic minority groups is important

schizophrenia is increased for black people and Asians compared with the local white population in Merton and Wandsworth.There seems, however, to be an additional risk for black people living in Wandsworth.There is a non-significant trend to a slightly increased risk of bipolar affective disorder.As a service driven instrument the long term case register does not have the epidemiological robustness of King and colleagues' study, but we do not consider our findings to be artefacts.The differences among ethnic groups have been stable over five years despite a 47% turnover of people on the register and a 70% change in the consultants making the clinical diagnoses.Furthermore, as mental health services are often considered to be inaccessible to ethnic minorities the long term case register may be expected to underestimate the