Differences in breast size have a significant impact on the mental health of adolescent girls, according to a recent study.

Researchers from Boston Children's Hospital found that asymmetrical breasts affect self-esteem, emotional well-being, and social functioning. They suggest that early intervention may have mental health benefits for young women with even relatively mild breast size differences.

"These findings suggest that patients suffering from breast asymmetry have poorer emotional well-being and lower self-esteem than their female peers," researcher Brian Labow said in a statement.

For the study, researchers evaluated psychosocial functioning and health-related quality of life in 59 adolescents and young women (12 to 21 years) with breast asymmetry. In all patients, the breasts differed by at least one bra cup size. Similar evaluations were performed in a group of girls without breast asymmetry, and in girls with macromastia (overlarge breasts).

About 40 percent of girls with breast asymmetry had tuberous breast deformity, a congenital condition in which the breasts don't develop normally.

Several aspects of mental health and well-being were lower for girls with breast asymmetry, compared to those with "normal" breasts. After adjustment for differences in body weight, breast asymmetry was associated with significantly lower scores for emotional well-being and self-esteem.

The differences were similar to those in girls with macromastia -- another common condition with a known mental health impact. Breast asymmetry was also associated with "borderline" issues in social functional and eating behaviors and attitudes.

Differences in breast size are common, especially in early adolescence. The breasts usually even out over time, but in some girls the difference persists after puberty. The new study is the first to focus on the mental health impact of breast asymmetry.

The psychosocial effects of breast asymmetry are similar to those in girls with overlarge breasts--as well as in boys with enlarged breasts and even women with differences in the breasts related to breast cancer surgery.

"The observed impaired psychological well-being of adolescents with breast asymmetry may indicate the need for early intervention to minimize negative outcomes," Labow said.

Researchers note that this doesn't necessarily mean surgery -- especially for younger girls, "consultation and support" may be appropriate. However, for girls who are finished growing and still have breast asymmetry, surgical correction may have important emotional benefits.

"Though substantial barriers to care exist, early evaluation and intervention for these patients may be beneficial, and should include weight control and mental health counseling," Dr. Labow and colleagues conclude.

The findings are detailed in the December issue of Plastic and Reconstructive Surgery.