• We reexamined case records from the Danish Extended Family Study to find so-called borderline schizophrenic (B3) persons who were clustered in the biologic relatives of chronic schizophrenic adoptees. A syndrome can be identified in these B3 cases that is distinguishable from borderline personality disorder and other personality disorders. Its discriminating features suggest that current DSM III criteria for schizotypal personality disorder be revised to include new criteria for somatization and social role dysfunction and a shift away from the past emphasis on psychoticlike experiences. Although the methodological limitations in this and other studies that have searched for a schizotype necessitate further research on the criteria for this new category, there is growing evidence to support its validity as a psychiatric diagnosis.