There are various factors that are known to affect the likelihood of childhood mental health conditions. These factors include premature birth, sex, BMI, maternal history of mental health disorders, and trauma.1,2 However, there is little research on the effect of birth order on the likelihood of childhood anxiety and depression. Understanding this could aid in identifying additional risk factors for mental health disorders.
We studied 182,477 children born between 2009 and 2016 who had a well-child visit during their eighth year of life, as this is when the U.S. Preventive Services Task Force suggests beginning anxiety screening.3 We adjusted for patient age, sex, race, ethnicity, history of other mental health disorders, mother’s history of anxiety or depression, insurance coverage type, premature birth, Social Vulnerability Index quintile, Rural Urban Commuting Area classification, and BMI.
Children born first who have siblings had a 48% greater likelihood of being diagnosed with anxiety by their eight-year well-child visit compared to children who were born second or later, as seen in Figure 1. Similarly, only children had a 42% greater likelihood of anxiety than children born second or later.
The likelihood of depression is higher for both firstborn children with siblings and only children, as seen in Figure 2. Firstborn children were 35% more likely to be diagnosed with depression compared to those who were born second or later, while only children were 38% more likely.
Original Publication Date: October 15, 2024
Last Updated: October 22, 2024
