Biological, psychological and historical differences in a series of monozygotic twins discordant for schizophrenia

A Prospective Cohort Study of Genetic and Perinatal Influences in the Etiology of Schizophrenia

“…Long-term followup of large birth cohorts on which detailed obstetric information is recorded Pollack et al 1966;Pollin and Stabenau 1968;Woerner et al 1971Woerner et al , 1973Jacobsen and Kinney 1980;Parnas et al 1982;Markow and Gottesman 1989;Eagles et al 1990;Bracha et al 1992;Fish et al 1992;O'Callaghan et al 1992;Buka et al 1993;Gunther-Genta et al 1994;Kinney et al 1994;McNeil et al 1994;Torrey et al 1994) in showing that complications representing direct and indirect indicators of fetal hypoxia are associated with an increased risk for schizophrenia. The present results also extend previous findings by demonstrating that odds of schizophrenia increase linearly with an increasing number of such complications.…”

“…Studies using objective measures of prenatal and perinatal history have consistently implicated OCs as risk factors for the disorder, whether the samples were siblings (Lane and Albee 1966;Pollack et al 1966;Woerner et al 1971;Eagles et al 1990;Gunther-Genta et al 1994;Kinney et al 1994) and twins (Pollin and Stabenau 1968;Markow and Gottesman 1989;Bracha et al 1992;Torrey et al 1994) discordant for schizophrenia, adopted children with schizophrenia (Jacobsen and Kinney 1980), offspring of parents diagnosed with schizophrenia (Parnas et al 1982;Fish et al 1992), adults diagnosed with schizophrenia and matched controls (O'Callaghan et al 1992;McNeil et al 1994;Kendell et al 1996;Hultman et al 1997), or representative birth cohorts (Done et al 1991;Buka et al 1993;Dalman et al 1999;Rosso et al, in press). The two studies reporting null results are not outliers in this respect, only in that the 95 percent confidence intervals of their risk estimates included values of 1 (Done et al 1991;Buka et al 1993).…”

Congenital risk factors for schizophrenia

“…The cotwin control method, usually a powerful method of isolating environmental risk factors, is open to similar inaccuracy. Assigning the right obstetric history to the right twin cannot be done with confidence, although the claim that adverse obstetric events occur in the schizophrenic twin in discordant monozygotic pairs is a thread which has run through twin studies from the beginning (Essen-Moller, 1941;Kallman, 1946;Inouye, 1963;Pollin & Stabenau, 1968;Torrey, 1977). One way round the problem is to compare within-pair birthweight differences in discordant pairs to that in concordant pairs.…”

Perinatal Distress and Prognosis of Psychotic Illness

“…Furthermore, studies on discordant monozygotic twins have revealed that perinatal insults were much more likely to involve the schizophrenic than the nonschi zophrenic twin [11]. McNeil and Kaij [13] reported that significantly more perinatal distress occurred in the his tories of process schizophrenics than other psychotic individuals.…”

“…Scientific studies indicate that several variables are valid prognostic indicators for psychosis [1][2][3][4][5][6][7], Several authors have noted an association be tween perinatal distress and the occurrence of schizo phrenia [8][9][10][11], yet little research has been done to assess the significance of perinatal trauma as a prognostic indi cator.…”