Between 14.4.60 and 30.9.60 a follow-up enquiry was carried out, combined with the genetical investigation which has been reported in previous pages. The informants for the genetical enquiry were also the ones who gave information about the patient's recent history. The period covered by follow-up was therefore from one to three years after the time at which hospital investigations had been carried out; and if related to the onset of the schizophrenia-like psychosis was at a mean period of 7.8 years later (range from 2 to 25 years). In addition to this the National Hospital patients have continued to be followed up from that time to the present date, as they and their relatives are asked to attend regularly at a follow-up clinic at the hospital. What is reported here relates to the findings in the special enquiry; but the data that have come in since do not suggest any modification of the conclusions that will be based on the survey of 1960. A synoptic view of these findings is given in Table I.