Babies born prematurely have a significantly greater risk of developing severe mental disorders such as bipolar disorder, depression, and psychosis later in life, according to a study published in the Archives of General Psychiatry on 04 June 2012. The study was conducted by British and Swedish scientists using the medical records of more than 1.3 million Swedes aged 16 and older who were admitted to hospitals and treated for mental disorders.
According to the study, babies born at less than 32 weeks’ gestation are 7.4 times more likely to be hospitalized with bipolar disorder, 3 times more likely to suffer from severe depression, and 2.5 times more likely to be diagnosed with psychosis as adults. Researchers also found that babies born after 32 to 36 weeks gestation have an increased likelihood of being diagnosed with a psychiatric illness as adults, though to a lesser degree than those born before 32 weeks.
The researchers who conducted the study believe the increased risk may be due to subtle but important differences in brain development in babies born before a full gestation period. The average length of gestation is estimated at 280 days, or 40 weeks. Full term is considered to be 37 to 42 weeks of gestation.
The study was led by Chiara Nosarti from the Institute of Psychiatry at King’s College London. She said the research showed a strong link between premature birth and psychiatric disorders at a briefing, telling reporters, “Since we considered only the most severe cases that resulted in hospitalization, it may be that in real terms this link is even stronger.”
Nosarti went on to stress, however, that “The majority of individuals who are born prematurely have no psychiatric or cognitive problems and are absolutely healthy and well-functioning.” She and her colleagues at the Karolinska Institute analyzed data from the medical records of people born between the years 1973 and 1985, singling out those admitted to a hospital with their first episode of a psychiatric disorder by 2002.
Previous studies have shown links between premature birth and numerous health and developmental problems. This study was the first to examine the possible link between premature births and psychiatric disorders. A United Nations-backed report published in May 2012 reported 15 million premature births in 2010, with the number steadily increasing due to advances in medicine throughout the world.
According to the World Health Organization, depression affects 121 million people worldwide and is one of the leading causes of disability. In the United States, nearly than 20 million people aged 18 and older—9.5% of the adult population—suffers from a mood disorder in any given year. Approximately 6 million American adults, or 2.6% of the adult population, have bipolar disorder; and 2.6 million, or 1.1% of the adult population, have schizophrenia.
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