Have you checked in with your eldest child lately?

The results of a new study suggest that your firstborn is the most likely to struggle with anxiety and depression, and the difference can be seen by age 8.

The data is based on information given to pediatricians at well-checks, cross-referenced with the child’s birth order, and adds a new dimension to mental health screening.

Oldest Child Syndrome

Birth order has certain obvious (and perhaps less obvious) effects on how one experiences the world.

For instance, a second-born child typically has someone a little older to observe as they undergo various experiences and developmental changes. A toddler who hasn’t yet held his first crayon can witness that his parents get angry when his older sibling colors on the wall, and before he’s allowed to attempt stairs on his own, he may watch how his older sibling navigates them.

Older children experience going from being their parents’ sole possession to having to share. They are often called on to help care for their younger sibling, whether it’s retrieving a dropped pacifier or babysitting. When there’s a new baby, for many kids, it’s their first experience of having to wait to have their needs met because their parents are taking care of a need for another person.

“Oldest child syndrome” is not a medical diagnosis, but it’s a term that has become accepted for describing the additional pressures firstborn siblings say they feel.

This New Study Shows The Emotional Effects

It’s now recommended to screen children as young as 8 for signs of anxiety disorders and to start screening for depressive disorders by age 12. This has come about with increased awareness of the mental pressures on children and an understanding of how hard a mental health struggle can be at a young age.

The collected data of nearly 200k children was adjusted for a slate of known factors, including the mother’s mental health, insurance type, BMI, gender, race and ethnicity, and Social Vulnerability Index. Even considering these factors, it turns out that a firstborn child is 48% more likely to be diagnosed with anxiety than their younger siblings, according to EpicResearch.

Depression rates are higher for the firstborn, too — they’re 35% more likely to be diagnosed with depressive disorders than kids with any other birth order position.

Children Without Siblings Are Also Affected

Based on the results of this study, an only child is 42% more likely to be diagnosed with anxiety compared to a child with older siblings. They’re also 38% more likely to suffer depressive disorders than children with older siblings.

The difference between children and children with siblings has been studied much more than the effects of birth order, so the data showing them to have higher levels of depression and anxiety isn’t quite as surprising. For instance, a 2020 study, carried out in China and published in the National Library of Medicine, found that among college students, the difference was stark.

Among only children, 30.7% had depressive symptoms, compared to 12.9% of students with siblings. Similar correlations were found with anxiety — 33.4% of only children had symptoms, compared to 17.4% of students with siblings.

Prior Data Shows Differences Between Eldest & Younger Children

A 2017 study published by the National Bureau of Economic Research found some differences between children based on birth order that may be related to these same stress levels and mental health disorders.

Eldest children tend to have higher levels of educational attainment and score better on certain tests of what the study labeled “non-cognitive skills,” including taking responsibility and initiative. On the other hand, they are more likely to have high blood pressure and to be overweight or obese.

This study posited that some of the differences may be attributable to different interactions. The authors noted:

“For example, based on evolutionary psychology, Frank J. Sulloway suggests that firstborns have an advantage in following the status quo, while later-borns — by having incentives to engage in investments aimed at differentiating themselves — become more sociable and unconventional in order to attract parental resources.”

Observable Differences By Birth Order

Research aside, experts in child development and psychology have described differences they see in children that vary by birth order.

These experts told VeryWell that firstborn children often have traits of an ingrained sense of responsibility, a sense of duty to meet expectations, an ambitious nature, a competitive nature, and a tendency to seek out leadership roles. At age 4, they may have a measurable advantage in literacy skills, verbal development, and use of numbers.

The other side of this is that they may feel pressured to be perfect and meet exacting standards. This can also present in a display of authoritarianism over younger siblings.

What Should Parents Do?

Some of these differences are difficult, if not impossible, to neutralize.

You can’t change the fact that your toddler has to wait for a snack when you’re feeding the newborn or that he has to be quieter when the baby needs a nap. However, we can be mindful of this and aware of the potential effects so that we can emphasize to our older children that the baby’s nap is not their responsibility.

We can also keep checking in with our older children about their responsibility levels. We can assure them that, while being a positive role model is good, they are not responsible for their younger siblings’ choices, behavior, or needs.

We can keep pouring love on them and making sure they know they’re loved, not for being the oldest, fastest, smartest, or best, but just for being themselves.