Relatively little research, however, has looked at whether these issues persist into adulthood.
The authors of the new study looked at 71 young adults who had been born extremely underweight, as well as 83 young adults who had been normal weight at birth.
Specifically, the researchers assessed four components of personality: temperament (shyness and sociability, neuroticism and extraversion), motivation (behavioral inhibition and behavioral activation), cognitive and affective (self-esteem, loneliness) and socialization.
The adults who had been extremely underweight at birth reported being shyer, having more behavioral inhibition, lower sociability, higher risk-aversion and a greater tendency to follow social convention. The results were the same for both men and women.
There were also differences within the extremely-low-birth-weight group, with lower birth weight linked to more shyness, behavioral inhibition and loneliness, among other traits.
But the study authors did provide one note of caution: The adults who had been born extremely underweight in this group also had similar relationships with peers, partners and family as the normal-birth-weight group.
The March of Dimes has more on low birth weight.
SOURCES: Louis A. Schmidt, Ph.D., professor of psychology, neuroscience and behavior, McMaster University, Hamilton, Ontario, Canada; Jane Ripperger-Suhler, M.D., assistant professor, psychiatry and behavioral science, Texas A&M Health Science Center College of Medicine, and psychiatrist, Scott & White Mental Health Center, Temple, Texas; July 2008, Pediatrics
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