July 02, 2005

Low Birth Weight Risk for Schiz.

Low Birth Weight a Risk Factor for Future Schizophrenia

More evidence that below-normal fetal birth weight is a risk factor for "increased psychological stress" later in life has just been published in the British Journal of Psychiatry. Results indicated that "children born full term but weighing less than 5.5 lbs (almost 3% of the total sample) had a 50% increased risk of psychological distress in later life." The risk was not associated with premature babies (those born before 38 weeks) - just below-weight babies born at full term.

In the study from the University of Bristol, Dr. Nicola Wiles and others examined data on 5572 participants in a 1950s study that included information on neonatal birthweight. They analyzed the data for possible connection between birth weight and later mental health problems in adult life.

Previous studies that have looked retrospectively at correlations between birth weight and adult mental health have been confounded by childhood factors such as IQ. It has been difficult in such studies to determine whether birth weight had a direct effect on adult mental health, or whether it simply marked children with problematic childhood factors that then caused them to have mental health problems as adults (thus making birthweight an indirect rather than a direct factor).

Authors of this study took into account these childhood factors. They found that an IQ of less than 100 at age seven was indeed associated with "greater psychological distress" in adulthood. But the independent association between low birth weight at full term and adult mental health problems was not weakened, even after correcting for child IQ and behavioral factors.

This study lends support to the theory that schizophrenia and other serious brain disorders are neurodevelopmental, meaning that some biological factors are in place or take place before or at birth. Throughout life, these predisposition factors may be exacerbated or not depending on the environment one is exposed to. Low birth-weight at term is a marker that fetal growth (including brain development) has been somehow slowed. More research is needed to determine how exactly this might happen, and whether some of the genes that have been linked to schizophrenia and bipolar disorder may somehow contribute to such growth retardation.

Prospective mothers can help lower their child's risk of having serious mental health problems by getting early and regular pre-natal care, taking pre-natal vitamins, and taking steps to avoid birth complications. If a baby is born with a low birth weight, this does NOT mean that the child is condemned to mental health problems - but it does mean that the parents might want to take extra care ensuring that the child grows up with an enriched social and nutritional environment, and that he/she is protected as much as possible from other risk factors (see http://www.schizophrenia.com/hypo.html) for mental illnesses.

Source: Low Birth Weight Linked to Psychological Distress in Adulthood. Science Daily (http://www.sciencedaily.com), July 2 2005.

View the study abstract free at: http://bjp.rcpsych.org/cgi/content/abstract/187/1/21


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