Severe malnourishment and other forms of deprivation for sustained periods during a child's early years may have lasting consequences on his or her intellectual development in later childhood.
Children who experienced such deprivation for more than 6 months after birth had lower IQ scores at age 11 years, despite their having been removed from the deprived environment for seven years or longer.
The findings are based on assessments of 131 Romanian children who lived in extremely deprived conditions in state institutions until the fall of the Ceausescu regime during the late 1980's, after which they were adopted into families living in the United Kingdom and Canada.
These children, who were adopted before 6 months of age, between 6 and 24 months of age, or between 24 and 43 months, were compared with 50 children who were born in the UK and adopted there by 6 months of age.
Previously published studies on the Romanian children, who usually entered the institutions as young babies, showed that those adopted before 6 months old were cognitively similar to the UK children, while those adopted at later ages had lower IQ scores. Yet, most children adopted at later ages reportedly experienced intellectual "catch-up" by age 4 or 6.
The researchers found that children with the lowest IQ scores at age 6, those adopted at the oldest ages, exhibited even further "catch-up" between the ages of 6 and 11.
The children who have been affected the worse continue to make progress over time, catching up a little with those who had not been so badly affected. Still, they, as well as other children adopted at later ages, continued to exhibit significant intellectual impairment at 11 years old.

In other findings, differences in the children's mental abilities at 11 years old, or changes in their cognitive abilities between 6 and 11 years old, were not associated with differences in their respective adoptive families.