Diagnostic criteria and follow-up findings on groups of children diagnosed by various investigators as childhood schizophrenic, autistic, or atypical are presented. Patients diagnosed by strict criteria believed to be indicative of severe disturbance by the originators of those criteria were, with few exceptions, severely disturbed at the time of follow-up. Those diagnosed by broader criteria showed a much greater variability in their social adjustment at the time of follow-up. Also presented are the results of studies attempting to find common physiologic abnormalities between childhood schizophrenics and a group of adult “process” schizophrenics. It is stated that to date no common physiologic abnormality has been found. The heterogeneity of the children found under the diagnosis of childhood schizophrenia and the need for a “marker” either physiologic or psychologic as a means of delimiting a more homogeneous group for study are stressed.