Low birth weight has been associated with schizophrenia throughout each era of investigation, but this association is not invariably found, and there was significant heterogeneity in the estimate for low birth weight (<2500 g) in this meta-analysis. The concept of a “population shift” in birth weight may account for this heterogeneity, and investigators using an arbitrary cutoff for low birth weight (i.e., <2500 g) will find inconsistent associations depending on the power of the study. Using a quantitative approach, Wahlbeck et al.  found that the risk of schizophrenia decreases in a linear fashion with increasing birth weight, increasing length at birth, and increasing placental weight. Low birth weight is usually due to prematurity or intrauterine growth retardation.

The lack of a significant association between risk of schizophrenia and prematurity in our meta-analysis indicates that the low birth weight is most likely due to intrauterine growth retardation (although there was no association between risk of schizophrenia and being small for gestational age). However, almost any factor adversely affecting the fetus will retard its growth, so these findings do not appreciably narrow our search. Low birth weight may be a proxy variable for some other adverse influence or influences on the developing fetus, whether of genetic or environmental origin. Women with schizophrenia or who later develop schizophrenia have been shown to be at increased risk of behaviors during pregnancy - such as smoking, taking medication, or poor attendance at antenatal clinics - that are associated with low birth weight outcomes.

The increased prevalence of congenital malformations found in this meta-analysis echoes the extensive literature on minor physical abnormalities and schizophrenia and further implicates pregnancy as a time when potential etiological factors may be operating.

Complications of delivery
The common mechanism for the delivery complications of asphyxia, uterine atony, and emergency Cesarean section found in our meta-analysis appears to be fetal hypoxia or anoxia. This is by no means a new idea, as anoxia has been mentioned since the earliest days of this literature. Geddes and colleagues concluded that the underlying mechanism for all the complications associated with schizophrenia in their meta-analysis was likely to involve fetal hypoxia but that a “more specific measure of exposure to hypoxia” was required. The pooled estimate for asphyxia in our meta-analysis demonstrated significant heterogeneity, possibly due to the different definitions of asphyxia used.

Three population-based studies that could not be included in the meta-analysis but that fulfilled three of the four inclusion criteria provide additional support for the involvement of fetal hypoxia or asphyxia in the etiology of schizophrenia . Individuals from the National Collaborative Perinatal Project with three or more hypoxia-related obstetric complications were more than five times more likely to develop schizophrenia than individuals with no hypoxia-related obstetric complications, and this finding was particularly marked among patients with early-onset schizophrenia. Siblings of schizophrenic subjects were no more likely to experience these complications than were comparison subjects.

Cannon and colleagues suggest that these results are consistent with a model of schizophrenia involving interaction of genetic vulnerability and obstetric complications and that the neurotoxic effect of fetal hypoxia leads to an early onset of schizophrenia through premature cortical synaptic pruning. Putative hypoxia-related complications have been related to brain structural abnormalities among schizophrenic patients.

The major difficulty with proposing hypoxic-ischemic damage as a causal risk factor for schizophrenia is the establishment of independence—it may be related to pregnancy complications, preexisting problems with the fetus, or maternal behaviors. Although some initial investigations have not found empirical support for this notion, few studies have had sufficient power to examine the interrelationships between various obstetric complications in the same individuals.

Mary Cannon, M.D., Ph.D., M.R.C.Psych., Peter B. Jones, M.D., Ph.D., M.R.C. Psych., and Robin M. Murray, M.D., D.Sc., F.R.C.Psych.

References

1. Rosanoff AJ, Handy LM, Plesset IR, Brush S: The etiology of so-called schizophrenic psychoses: with special reference to their occurrence in twins. Am J Psychiatry 1934; 91:247-286
2. Pasamanick B, Rogers ME, Lilienfield AM: Pregnancy experience and the development of behavior disorder in children. Am J Psychiatry 1956; 112:613-618
3. Hinton GG: Childhood psychosis or mental retardation: a diagnostic dilemma, II: paediatric and neurologic aspects. Can Med Assoc J 1963; 89:1020-1024
4. Taft L, Goldfarb W: Prenatal and perinatal factors in childhood schizophrenia. Dev Med Child Neurol 1964; 6:32-43
5. Terris M, Lapouse R, Monk MA: The relation of prematurity and previous fetal loss to childhood schizophrenia. Am J Psychiatry 1964; 121:476-481
6. Voster D: An investigation of the part played by organic factors in childhood schizophrenia. J Ment Sci 1960; 106:494-522
7. Pollack M, Woerner MG: Pre- and perinatal complications and "childhood schizophrenia": a comparison of five controlled studies. J Child Psychol Psychiatry 1966, 7:235-242
8. Torrey EF, Hersch SP, McCabe KD: Early childhood psychosis and bleeding during pregnancy. J Autism Child Schizophr 1975; 5:287-297
9. Lane EA, Albee GW: Comparative birth weights of schizophrenics and their siblings. J Psychol 1966; 64:227-231
10. Stabenau JR, Pollin W: Early characteristics of monozygotic twins discordant for schizophrenia. Arch Gen Psychiatry 1967; 17:723-734
11. Pollack M, Woerner MG, Goodman W, Greenberg I: Childhood developmental patterns of hospitalized adult schizophrenic patients and non-schizophrenic patients and their siblings. Am J Orthopsychiatry 1966; 36:510-517
12. Woerner MG, Pollack M, Klein DF: Birth weight and length in schizophrenics, personality disorders and their siblings. Br J Psychiatry 1971; 118:461-464
13. Woerner MG, Pollack M, Klein DF: Pregnancy and birth complications in psychiatric patients: a comparison of schizophrenic and personality disorder patients with their siblings. Acta Psychiatr Scand 1971; 49:712-721
14. Jones PB: Longitudinal approaches to the search for the causes of schizophrenia: past, present and future, in Search for the Causes of Schizophrenia, vol IV: Balance of the Century. Edited by Gattaz WF, Hafner H. New York, Springer-Verlag, 1999, pp 91-119
15. Mednick SA, Schulsinger F: Some premorbid characteristics related to breakdown in children with schizophrenic mothers. J Psychiatr Res 1968; 6(suppl):267
16. Mednick SA: Breakdown in individuals at high risk for schizophrenia: possible predispositional perinatal factors. Ment Hyg 1970; 54:51-63
17. Sobel D: Infant malformations and mortality in children of schizophrenic parents. Psychiatr Q 1961; 35:60-64
18. Rieder RO, Rosenthal D, Wender P, Blumenthal H: The offspring of schizophrenics, I: fetal and neonatal deaths. Arch Gen Psychiatry 1975; 32:200-211
19. Modrzewska K: The offspring of schizophrenic parents in a North Swedish isolate. Clin Genet 1980; 17:191-201
20. Rieder RO, Broman SH, Rosenthal D: The offspring of schizophrenics, II: perinatal factors and IQ. Arch Gen Psychiatry 1977; 34:789-799
21. Wrede G, Mednick SA, Huttunen MO, Nilsson CG: Pregnancy and delivery complications in the births of an unselected series of Finnish children with schizophrenic mothers. Acta Psychiatr Scand 1980; 62:369-381
22. McNeil TF, Kaij L: Obstetric complications and physical size of offspring of schizophrenic, schizophrenic-like and control mothers. Br J Psychiatry 1973; 123:341-381
23. Mirdal GKM, Mednick SA, Schulsinger F, Fuchs F: Perinatal complications in children of schizophrenic mothers. Acta Psychiatr Scand 1974; 50:553-568
24. Cohler BJ, Gallant DH, Grunebaum HU, Weiss JL, Gamer E: Pregnancy and birth complications among mentally ill and well mothers and their children. Soc Biol 1975; 22:269-278
25. Hanson DR, Gottesman II, Heston LC: Some possible indicators of adult schizophrenia inferred from children of schizophrenics. Br J Psychiatry 1976; 129:142-154
26. Sameroff AJ, Zax M: Perinatal characteristics of the offspring of schizophrenic women. J Nerv Ment Dis 1973; 157:191-199
27. Zax M, Sameroff AJ, Babigian HM: Birth outcomes in the offspring of mentally disordered women. Am J Orthopsychiatry 1977; 47:218-230
28. McNeil TF, Kaij L: Obstetric factors in the development of schizophrenia: complications in the births of preschizophrenics and in reproduction by schizophrenic parents, in The Nature of Schizophrenia: New Approaches to Research and Treatment. Edited by Wynne LC, Cromwell RL, Mathysse S. New York, John Wiley & Sons, 1978, pp 401-429
29. . Sacker A, Done DJ, Crow TJ: Obstetric complications in children born to parents with schizophrenia: a meta-analysis of case-control studies. Psychol Med 1996; 26:279-287
30. Jacobsen B, Kinney DK: Perinatal complications in adopted and non-adopted schizophrenics and their controls: preliminary results. Acta Psychiatr Scand Suppl 1980; 285:337-346
31. Parnas J, Schulsinger F, Teasdale TW, Schulsinger H, Feldman PM, Mednick SA: Perinatal complications and clinical outcome within the schizophrenia spectrum. Br J Psychiatry 1982; 140:416-420
32. DeLisi LE, Goldin LR, Maxwell E, Karuba DM, Gershon ES: Clinical features of illness in siblings with schizophrenia or schizoaffective disorder. Arch Gen Psychiatry 1987; 44:891-896
33. Johnstone EC, Crow TJ, Frith CD, Husband J, Kreel L: Cerebral ventricular size and cognitive impairment in chronic schizophrenia. Lancet 1976; 2:924-926
34. Weinberger DR, DeLisi LE, Perman G, Targum S, Wyatt RJ: Computed tomography scans in schizophreniform disorder and other acute psychiatric disorders. Arch Gen Psychiatry 1982; 39:778-783
35. Schulsinger F, Parnas J, Petersen ET, Schulsinger H, Teasdale TW, Mednick SA, Moller L, Silverton L: Cerebral ventricular size in the offspring of schizophrenic mothers "a preliminary study. Arch Gen Psychiatry 1984; 41:602-606
36. Reveley AM, Reveley MA, Murray RM: Cerebral ventricular enlargement in non-genetic schizophrenia: a controlled twin study. Br J Psychiatry 1984; 144:89-93
37. Murray RM, Lewis SW, Reveley AM: Towards an aetiological classification of schizophrenia. Lancet 1985; 1:1023-1026
38. Andreasen N, Nasrallah HA, Dunn V, Olson SC, Grove WM, Ehrhardt JC, Coffman JA, Crossett JHW: Structural abnormalities in the frontal system in schizophrenia. Arch Gen Psychiatry 1986; 43:136-144
39. Weinberger DR: The pathogenesis of schizophrenia: a neurodevelopmental theory, in The Neurology of Schizophrenia. Edited by Nasrallah HA, Weinberger DR. Amsterdam, Elsevier, 1986, pp 397-406
40. Murray RM, Lewis SW: Is schizophrenia a neurodevelopmental disorder? (editorial) Br Med J 1987; 295:681-682
41. Weinberger DR: Implications of normal brain development for the pathogenesis of schizophrenia. Arch Gen Psychiatry 1987; 44:660-669
42. Lewis SW, Murray RM: Obstetric complications, neurodevelopmental deviance and risk of schizophrenia. J Psychiatr Res 1987; 21:413-421
43. Lewis SW, Owen MJ, Murray RM: Obstetric complications and schizophrenia: methodology and mechanisms, in Schizophrenia: Scientific Progress. Edited by Schultz SC, Tamminga CA. New York, Oxford University Press, 1989, pp 56-68
44. Eagles JM, Gibson I, Bremner MH, Clunie F, Ebmeier KP, Smith NC: Obstetric complications in DSM-III schizophrenics and their siblings. Lancet 1990; 335:1139-1141
45. O'Callaghan E, Gibson T, Colohan HA, Buckley P, Walshe DG, Larkin C, Waddington JL: Risk of schizophrenia in adults born after obstetric complications and their association with early onset of illness: a controlled study. Br Med J 1992; 305:1256-1259
46. Verdoux H, Bourgeois M: A comparative study of obstetric history in schizophrenics, bipolar patients, and normal subjects. Schizophr Res 1993; 9:67-69
47. Gunther-Genta F, Bovet P, Hohlfield P: Obstetric complications and schizophrenia: a case-control study. Br J Psychiatry 1994; 164:165-170
48. Hultman CM, O"hman A, Cnattingius S, Wieselgren I-M, Lindstro"m LH: Prenatal and neonatal risk factors for schizophrenia. Br J Psychiatry 1997; 170:128-133
49. McCreadie RG, Hall DJ, Berry IJ, Robertson LJ, Ewing JI, Geals MF: The Nithsdale schizophrenia surveys, X: obstetric complications, family history and abnormal movements. Br J Psychiatry 1992; 160:799-805
50. Heun R, Maier W: The role of obstetric complications in schizophrenia. J Nerv Ment Dis 1993; 181:220-226
51. Foerster A, Lewis SW, Owen MJ, Murray R: Low birth weight and a family history of psychosis predict poor premorbid functioning in psychosis. Schizophr Res 1991; 5:13-20
52. Rifkin L, Lewis S, Jones P, Toone B, Murray R: Low birth weight and schizophrenia. Br J Psychiatry 1994; 165:357-362
53. Smith GN, Kopala LC, Lapointe JS, MacEwan GW, Altman S, Flynn SW, Schnieder T, Falkai P, Honer WG: Obstetric complications, treatment response and brain morphology in adult onset and early-onset males with schizophrenia. Psychol Med 1998; 28:645-653
54. Willinger U, Heiden A, Mesaros K: Obstetric complications, premorbid and current cognitive functioning in schizophrenics and their same sex healthy siblings (abstract). Schizophr Res 1996; 18:100
55. O'Callaghan E, Larkin C, Kinsella A, Waddington JL: Obstetric complications, the putative familial-sporadic distinction and tardive dyskinesia in schizophrenia. Br J Psychiatry 1990; 157:578-584
56. McNeil TF, Cantor-Graae E, Nordstrom LG, Rosenlund T: Head circumference in "preschizophrenic" and control neonates. Br J Psychiatry 1993; 162:517-523
57. Kunugi H, Takei N, Murray RM, Saito K, Nanko S: Small head circumference at birth in schizophrenia. Schizophr Res 1996; 20:165-170
58. Owen MJ, Lewis SW, Murray RM: Obstetric complications and schizophrenia: a computed tomographic study. Psychol Med 1998; 18:331-339
59. Kirov G, Jones PB, Harvey I, Lewis SW, Toone BK, Rifkin L, Sham P, Murray RM: Do obstetric complications cause the earlier age at onset in male than female schizophrenics? Schizophr Res 1996; 20:117-124
60. Nicolson R, Malaspina D, Giedd JN, Hamburger S, Lenane M, Bedwell J, Fernandez T, Berman A, Susser E, Rapoport JL: Obstetrical complications and childhood-onset schizophrenia. Am J Psychiatry 1999; 156:1650-1652
61. Hutchinson G, Takei N, Bhugra D, Fahy TA, Gilvarry C, Mallett R, Moran P, Leff J, Murray RM: Increased rate of psychosis among African-Caribbeans in Britain is not due to an excess of pregnancy and birth complications. Br J Psychiatry 1997; 171:145-147
62. Kuller LH: Circular epidemiology. Am J Epidemiol 1999; 150:897-903
63. Geddes JR, Lawrie SM: Obstetric complications and schizophrenia: a meta-analysis. Br J Psychiatry 1995; 167:786-793
64. Geddes JR, Verdoux H, Takei N, Lawrie SM, Bovet P, Eagles JM, Heun R, McCreadie RG, McNeil TF, O'Callaghan E, Sto"ber G, Willinger U, Murray RM: Schizophrenia and complications of pregnancy and labor: an individual-patient data meta-analysis. Schizophr Bull 1999; 25:413-423
65. Fleiss JL: The statistical basis of meta-analysis. Stat Methods Med Res 1993; 2:121-145
66. Egger M, Smith GD, Phillips AN: Meta-analysis: principles and procedures. Br Med J 1997; 315:1533-1537
67. Sacker A, Done DJ, Crow TJ, Golding J: Antecedents of schizophrenia and affective illness: obstetric complications. Br J Psychiatry 1995; 166:734-741
68. Jones PB, Rantakallio P, Hartikainen A-L, Isohanni M, Sipila P: Schizophrenia as a long-term outcome of pregnancy, delivery, and perinatal complications: a 28-year follow-up of the 1966 North Finland general population birth cohort. Am J Psychiatry 1998; 155:355-364
69. Hultman CM, Sparen P, Takei N, Murray RM, Cnattingius S: Prenatal and perinatal risk factors for schizophrenia, affective psychosis, and reactive psychosis of early onset: case-control study. Br Med J 1999; 318:421-426
70. Dalman C, Allebeck P, Cullberg J, Grunewald C, Ko"ster M: Obstetric complications and the risk of schizophrenia: a longitudinal study of a national birth cohort. Arch Gen Psychiatry 1999; 56:234-240
71. Kendell RE, McInneny K, Jusczak E, Bain M: Obstetric complications and schizophrenia: two case-control studies based on structured obstetric records. Br J Psychiatry 2000; 174:516-522
72. Byrne M, Browne R, Mulryan N, Scully A, Morris M, Kinsella A, Takei N, McNeil T, Walsh D, O'Callaghan E: Labour and delivery complications and schizophrenia: case-control study using contemporaneous labour ward records. Br J Psychiatry 2000; 176:531-536
73. Dalman C, Thomas HV, David AS, Gentz J, Lewis G, Allebeck P: Signs of asphyxia at birth and risk of schizophrenia: population-based case-control study. Br J Psychiatry 2001; 179:415-416
74. Done DJ, Johnstone EC, Frith CD, Golding J, Shepherd PM, Crow TJ: Complications of pregnancy and delivery in relation to psychosis in adult life: data from the British Perinatal Mortality Survey sample. Br Med J 1991; 302:1576-1580
75. Buka SL, Tsuang MT, Lipsitt LP: Pregnancy/delivery complications and psychiatric diagnosis: a prospective study. Arch Gen Psychiatry 1993; 50:151-156
76. Cannon TD, Rosso IM, Hollister JM, Bearden CE, Sanchez, Hadley T: A prospective cohort study of genetic and perinatal influences in the etiology of schizophrenia. Schizophr Bull 2000; 26:249-256
77. Rosso IM, Cannon TD, Huttunen T, Huttunen MO, Lo"nnqvist J, Gasperoni TL: Obstetric risk factors for early-onset schizophrenia in a Finnish birth cohort. Am J Psychiatry 2000; 157:801-807
78. Zornberg GL, Buka SL, Tsuang MT: Hypoxic-ischemia-related fetal/neonatal complications and risk of schizophrenia and other nonaffective psychoses: a 19-year longitudinal study. Am J Psychiatry 2000; 157:196-202
79. DerSimonian R, Laird N: Meta-analysis in clinical trials. Control Clin Trials 1986; 7:177-188
80. Kendell RE, Juszczack E, Cole SK: Obstetric complications and schizophrenia: a case-control study based on standardised obstetric records. Br J Psychiatry 1996; 168:556-561
81. Scott JR: Vaginal bleeding in the midtrimester of pregnancy. Am J Obstet Gynecol 1972; 113:329-334
82. Schaefer C, Brown AS, Wyatt RJ, Kline J, Begg MD, Bresnahan MA, Susser ES: Maternal prepregnant body mass and risk of schizophrenia in the offspring. Schizophr Bull 2000; 26:275-286
83. Eriksson UJ: The pathogenesis of congenital malformations in diabetic pregnancy. Diabetes Metab Rev 1995; 11:63-82
84. Wright P, Sham PC, Gilvarry CM, Jones PB, Cannon M, Sharma T, Murray RM: Autoimmune diseases in the pedigrees of schizophrenic and control subjects. Schizophr Res 1996; 20:261-267
85. Gilvarry CM, Sham PC, Jones PB, Cannon M, Wright P, Lewis SW, Bebbington P, Toone BK, Murray RM: Family history of autoimmune diseases in psychosis. Schizophr Res 1996; 19:33-40
86. Hollister JM, Brown AS: Rhesus incompatibility and schizophrenia, in Prenatal Exposures in Schizophrenia. Edited by Susser ES, Brown AS, Gorman JM. Washington, DC, American Psychiatric Press, 1999, pp 197-214
87. Hollister JM, Kohler C: Schizophrenia: a long-term complication of haemolytic disease of the fetus and newborn? Int J Ment Health 2001; 29:38-61
88. Hollister JM, Laing P, Mednick SA: Rhesus incompatibility as a risk factor for schizophrenia in male adults. Arch Gen Psychiatry 1996; 53:19-24
89. Dalman C, Cullberg J: Neonatal hyperbilirubinemia "a vulnerability factor for mental disorder? Acta Psychiatr Scand 1999; 100:469-471
90. Ichiki M, Kunugi H, Takei N, Murray RM, Baba H, Arai H, Oshima I, Okagami K, Sato T, Hirose T, Nanko S: Intra-uterine physical growth in schizophrenia: evidence confirming excess of premature birth. Psychol Med 2000; 30:597-604
91. Wahlbeck K, Forsen T, Osmond C, Barker DJP, Eriksson JG: Association of schizophrenia with low maternal body mass index, small size at birth and thinness during childhood. Arch Gen Psychiatry 2001; 58:48-52
92. Bennedsen BE: Adverse pregnancy outcome in schizophrenic women: occurrence and risk factors. Schizophr Res 1998; 33:1-26
93. Lane A, Kinsella A, Murphy P, Byrne M, Keenan J, Colgan K, Cassidy B, Sheppard N, Horgan R, Waddington JL, Larkin C, O'Callaghan E: The anthropometric assessment of dysmorphic features in schizophrenia as an index of its developmental origins. Psychol Med 1996; 27:1155-1164
94. McNeil T, Cantor-Graae E, Ishmail B: Obstetric complications and congenital malformations in schizophrenia. Brain Res Brain Res Rev 2000; 31:166-178
95. Cannon TD, Mednick SA, Parnas J, Schulsinger F, Praestholm J, Vestergaard A: Developmental brain abnormalities in the offspring of schizophrenic mothers, I: contributions of genetic and perinatal factors. Arch Gen Psychiatry 1993; 50:551-564
96. Cannon TD: On the nature and mechanisms of obstetric influences in schizophrenia: a review and synthesis. Int Rev Psychiatry 1997; 9:387-397
97. McNeil TF, Cantor-Graae E, Weinberger DR: Relationship of obstetric complications and differences in size of brain structures in monozygotic twin pairs discordant for schizophrenia. Am J Psychiatry 2000; 157:203-212
98. Goodman R: Are complications of pregnancy and birth causes of schizophrenia? Dev Med Child Neurol 1990; 30:391-406
99. Nelson KB, Ellenberg JH: Antecedents of cerebral palsy: multivariate analysis of risk. N Engl J Med 1986; 315:81-86
100. McNeil TF, Cantor-Graae E: Does pre-existing abnormality cause labor-delivery complications in fetuses who will develop schizophrenia? Schizophr Bull 1999; 25:425-435
101. Wald NJ, Nanachal K, Thompson SG, Cuckle HS: Does breathing other people's tobacco smoke cause lung cancer? Br Med J (Clin Res Ed) 1986; 293:1217-1222
102. Collaborative Group on Hormonal Factors in Breast Cancer: Breast cancer and hormonal contraceptives: collaborative reanalysis of individual data of 53,297 women with breast cancer and 100,239 women without breast cancer from 54 epidemiological studies. Lancet 1996; 347:1713-1727
103. Taubes G: Epidemiology faces its limits. Science 1995; 269:164-169
104. Cannon M, Jones P, Gilvarry C, Rifkin L, McKenzie K, Foerster A, Murray RM: Premorbid social functioning in schizophrenia and bipolar disorder: similarities and differences. Am J Psychiatry 1997; 154:1544-1550
105. Zornberg G, Buka SL, Tsuang MT: The problem of obstetrical complications and schizophrenia. Schizophr Bull 2000; 26:249-256
106. McNeil TF Perinatal risk factors and schizophrenia: selective review and methodological concerns. Epidemiol Rev 1995; 17:107-112
107. Bagalkote H, Pang D, Jones P: Maternal influenza and schizophrenia in the offspring. Int J Ment Health 2001; 29:3-21
108. Brown AS: Prenatal infection and adult schizophrenia: a review and synthesis. Int J Ment Health 2001; 29:22-37
109. Susser E, Lin SP: Schizophrenia after prenatal exposure to the Dutch Hunger Winter of 1944-1945. Arch Gen Psychiatry 1992; 49:983-988
110. Huttunen M, Niskanen P: Prenatal loss of father and psychiatric disorders. Arch Gen Psychiatry 1978; 35:427-431
111. Kinney DK: Prenatal stress and risk for schizophrenia. Int J Ment Health 2001; 29:62-71
112. Brown AS, Cohen P, Greenwald S, Susser E: Nonaffective psychosis after prenatal exposure to rubella. Am J Psychiatry 2000; 157:438-443
113. Stewart AL, Rifkin L, Amess PN, Kirkbride V, Townsend JP, Miller DH, Lewis SW, Kingsley DPE, Moseley IF, Foster O, Murray RM: Brain structure and neurocognitive and behavioural function in adolescents who were born very preterm. Lancet 1999; 353:1653-1657
114. Verdoux H, Geddes JR, Takei N, Lawrie SM, Bovet P, Eagles JM, Heun R, McCreadie RG, McNeil TF, O'Callaghan E, Sto"ber G, Willinger U, Wright P, Murray RM: Obstetric complications and age at onset in schizophrenia: an international collaborative meta-analysis of individual patient data. Am J Psychiatry 1997; 154:1220-1227
115. Van Os J, Marcelis M: The ecogenetics of schizophrenia: a review. Schizophr Res 1998; 32:127-135
116. Susser E, Schaefer C, Brown A, Begg M, Wyatt RJ: The design of the Prenatal Determinants of Schizophrenia Study (PDS). Schizophr Bull 2000; 26:257-274
117. Kandel ER: A new intellectual framework for psychiatry. Am J Psychiatry 1998; 155:457-469
118. Fearon P, Cannon M, Murray RM: A critique of the idea and science of risk-factor research in schizophrenia. Int J Ment Health 2001; 30:82-90
119. Benes FM: Emerging principles of altered neural circuitry in schizophrenia. Brain Res Brain Res Rev 2000; 31:251-269
120. Susser M, Susser E: Choosing a future for epidemiology, II: from black boxes to Chinese boxes and eco-epidemiology. Am J Public Health 1996; 86:674-677
121. Cotter D, Takei N, Farrell M, Sham PC, Quinn P, Larkin C, O'Callaghan E: Does prenatal exposure to influenza in mice induce pyramidal cell disarray in the dorsal hippocampus? Schizophr Res 1995; 16:233-241
122. Fatemi SH, Emamian ES, Kist D, Sidwell RW, Nakajima K, Akhter P, Shier A, Sheikh S, Bailey K: Defective corticogenesis and reduction in Reelin immunoreactivity in cortex and hippocampus of prenatally infected neonatal mice. Mol Psychiatry 1999; 4:145-154
123. Buka SL, Tsuang MT, Torrey EF, Klebanoff MA, Bernstein D, Yolken RH: Maternal infections and subsequent psychosis among offsrping. Arch Gen Psychiatry 2001; 58:1032-1037
124. Jones P, Cannon M: The new epidemiology of schizophrenia. Psychiatr Clin North Am 1998; 21:1-26

Source: http://ajp.psychiatryonline.org/cgi/content/full/159/7/1080