Individual differences |
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Perinatal brain development
It is thought that some of the neuroanatmical features associated with early neurodevelopment, including during pregnancy, to increase the risk of later developing schizophrenia. One curious finding is that people diagnosed with schizophrenia are more likely to have been born in winter or spring (at least in the northern hemisphere).
- Main article: Schizophrenia - Season of birth
However, the effect is not large. Some researchers postulate that the correlation is due to viral infections during the third trimester (4-6 months) of pregnancy. There is now significant evidence that prenatal exposure to infections increases the risk for developing schizophrenia later in life, providing additional evidence for a link between in utero developmental pathology and risk of developing the condition.
- Main article: Schizophrenia - Link with early infection
A study by Sweden's Karolinska Institute and Bristol University in the UK, looked at the medical records of over 700,000 people and calculated that 15.5% of cases of schizophrenia seen in the group may have been due to the patient having a father who was aged over 30 years at their birth, the researchers argue this is due to build up of mutations in the sperm of elder fathers.
- Main article: Schizophrenia - Age of parents
Women who were pregnant during the Dutch famine of 1944, where many people were close to starvation, had a higher chance of having a child who would later develop schizophrenia. Similarly, studies of Finnish mothers who were pregnant when they found out that their husbands had been killed during the Winter War of 1939–1940 have shown that their children were much more likely to develop schizophrenia when compared with mothers who found out about their husbands' death after pregnancy, suggesting that even psychological trauma in the mother may have an effect.
Childhood and adolescent development
Schizophrenia is most commonly first diagnosed during late adolescence or early adulthood suggesting it is often the end process of childhood and adolescent development. Studies have indicated that genetic dispositions can interact with early environment to increase the risk of developing schizophrenia, including through global neurobehavioral deficits, a poorer family environment and disruptive school behaviour, poor peer engagement, immaturity or unpopularity or poorer social competence and increasing schizophrenic symptomology emerging during adolescence These developmental problems have also been linked to socioeconomic disadvantage or early experiences of traumatic events.
There is on average a somewhat earlier onset for men than women, with the possible protective influence of the female hormone oestrogen being one hypothesis made and sociocultural influences another.
References & Bibliography
- ↑ Davies G, Welham J, Chant D, Torrey EF, McGrath J. (2003) A systematic review and meta-analysis of Northern Hemisphere season of birth studies in schizophrenia. Schizophrenia Bulletin, 29 (3),587–93.
- ↑ Brown, A.S. (2006) Prenatal infection as a risk factor for schizophrenia. Schizophrenia Bulletin, 32 (2), 200-2.
- ↑ Cite error: Invalid
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- ↑ Susser E, Neugebauer R, Hoek HW, Brown AS, Lin S, Labovitz D, Gorman JM (1996) Schizophrenia after prenatal famine. Further evidence. Archives of General Psychiatry, 53(1), 25–31.
- ↑ Huttunen MO, Niskanen P. (1978) Prenatal loss of father and psychiatric disorders. Archives of General Psychiatry, 35(4), 429–31.
- ↑ Hans SL, Marcus J, Nuechterlein KH, Asarnow RF, Styr B, Auerbach JG. (1999) Neurobehavioral deficits at adolescence in children at risk for schizophrenia: The Jerusalem Infant Development Study. Arch Gen Psychiatry. 56(8):741-8.
- ↑ Carter JW, Schulsinger F, Parnas J, Cannon T, Mednick SA. (2002) A multivariate prediction model of schizophrenia. Schizophrenia Bulletin 28(4):649-82.
- ↑ Hans SL, Auerbach JG, Asarnow JR, Styr B, Marcus J. (2000) Social adjustment of adolescents at risk for schizophrenia: the Jerusalem Infant Development Study. J Am Acad Child Adolesc Psychiatry. 39(11):1406-14.
- ↑ Dworkin RH, Bernstein G, Kaplansky LM, Lipsitz JD, Rinaldi A, Slater SL, Cornblatt BA, Erlenmeyer-Kimling L. (1991) Social competence and positive and negative symptoms: a longitudinal study of children and adolescents at risk for schizophrenia and affective disorder. Am J Psychiatry. Sep;148(9):1182-8.
- ↑ Read J, Perry BD, Moskowitz A, Connolly J (2001) The contribution of early traumatic events to schizophrenia in some patients: a traumagenic neurodevelopmental model. Psychiatry, 64, 319-45. (full text)