In a controlled follow-up study into adulthood of 32 children diagnosed 'schizoid', three-quarters fulfilled DSM-III criteria for schizotypal personality disorder and two developed schizophrenia. Overall their psychosocial adjustment was somewhat, but not markedly, worse than that of other attenders at a child psychiatry clinic, although as a group they remained more solitary, lacking in empathy, oversensitive, with odd styles of communicating, and often with circumscribed interests.

The auditory P300 response and smooth pursuit eye tracking were recorded from a group of 23 male adult subjects who had been diagnosed in childhood as having schizoid personality. No differences were found in these physiological measures between the study group, their matched controls of other child psychiatric patients, and a group of population controls. The essentially negative findings are discussed in the light of abnormalities of these psychophysiological responses previously found in schizophrenic patients, in some of their biological relatives, and in other groups of psychiatric patients, including autistic children and adults with a diagnosis of borderline and schizotypal personality disorder. Results suggest that "schizoid" children, despite their high scores on a measure of schizotypy, do not have schizophrenia spectrum disorder or that schizotypy is a heterogeneous condition.