Young adults who were born at a very low weight may have a higher-than-average rate of some psychological problems, a new study suggests.

Researchers found an increased risk of anxiety, depression and certain other psychological symptoms among a group of 20-year-olds who were born at extremely low weights.

Based on reports from study participants and their parents, low-birthweight females had more “internalizing” symptoms - anxiety, depression and a tendency to be withdrawn - than their peers who were born at a normal weight.

When it came to males, parents of the low-birthweight subjects reported more attention problems, as well as more so-called thought problems - schizophrenia-like symptoms such as hearing voices or having “strange ideas.” None of the young adults in the study had schizophrenia, however.

Moreover, none of the findings should cause parents of premature infants to worry that their children are destined to have psychological disorders, lead author Dr. Maureen Hack told Reuters Health.

For one thing, the majority of these low-birthweight adults were not suffering anxiety, depression or other such symptoms, noted Hack, who is with Case Western Reserve University in Cleveland.

Hack said that parents can take the findings, reported in the journal Pediatrics, as “anticipatory guidance.” That is, if their children appear particularly anxious or withdrawn at a young age, parents may want to consult their doctors.

Doing so, Hack said, may help head off problems in young adulthood.

The researchers followed 241 very-low-birthweight infants born between 1977 and 1979. On average, the children were born about 10 weeks early and weighed just over 2.5 pounds.

At age 20, they and their parents completed standard questionnaires meant to tap into young adults’ behaviors, thoughts and feelings, but not designed to diagnose psychological disorders. Their results were compared with those of 233 20-year-olds with normal birth weights.

Because it was not until recent decades that such tiny preemies were able to survive, Hack noted, little is known about how they fare as adults.

In a recent study of the same group, she and her colleagues found that 20-year-olds in the low-birthweight group continued to show some intellectual deficits that had been apparent in childhood - namely, lower scores on IQ and academic tests.

But they also showed less “risk-taking,” such as drinking or using drugs. Similarly, in the new study, females and males in the low birthweight group had lower rates of delinquency.

As for why tiny newborns may be more prone to psychological difficulties later in life, a number of factors are likely to play a role, according to Hack. It’s known that these children grow up differently from others in certain ways - showing more learning problems even when their intelligence is normal, for example.

In addition, Hack noted, parents’ behavior could factor in. Mothers of very small preemies tend to have more postnatal depression, she said, and parents who have faced the possibility of losing their newborn may be more anxious and overprotective of their children over the long term.

SOURCE: Pediatrics, October 2004.