Am J Psychiatry 1994; 151:1194-1199
Copyright © 1994 by American Psychiatric Association
Are neurological abnormalities in well discordant monozygotic co-twins of schizophrenic subjects the result of perinatal trauma?
E Cantor-Graae, TF McNeil, KC Rickler, K Sjostrom, R Rawlings, ES Higgins and TM Hyde
Department of Psychiatry, Lund University, Sweden.
OBJECTIVE: Neurological abnormalities found in schizophrenic subjects and
their healthy relatives have raised questions concerning etiology. The aim
of the present study was to investigate the genetic and environmental
antecedents of neurological impairment in monozygotic twins discordant for
schizophrenia, with particular focus on the well discordant twins. The
etiological factors of interest were history of obstetric complications,
family history of psychosis, history of substance abuse, and history of
postnatal cerebral trauma. METHOD: History of obstetric complications,
including information from pregnancy through the neonatal period, and data
on neurological "hard" and "soft" signs were obtained blindly and
separately for each member of 22 monozygotic twin pairs discordant for
schizophrenia and seven normal comparison monozygotic twin pairs. Clinical
and family interviews provided information about background factors.
RESULTS: Degree of neurological impairment in the well discordant
monozygotic twins was significantly positively related to history of both
neonatal and total obstetric complications. None of the three other
background factors investigated was related to degree of neurological
impairment in the ill or well co-twins. CONCLUSIONS: The contribution of
obstetric complications to the current level of neurological impairment in
well discordant co-twins suggests that the spectrum of neuroabnormality,
ranging from neurological signs to schizophrenia, in monozygotic discordant
twins may be the result of subtle gene-environment interaction.
