Gagandeep Kaur, M.D.,  Kanwarjeet Singh Brar, M.D., Steven Lippmann, M.D.

Birth order is defined as the sequential order in which siblings are born (1). Discussion about this issue began in the 19^th century (2). Since birth order confers a strong impact on development, inquire about birth order when eliciting a history.

There are five variables that reflect difference in the personalities of first-born, later-born, and an only child. These “Big Five” are: agreeableness, conscientiousness, extraversion, neuroticism, and openness to new experiences (2,3). Birth order may be a risk factor for schizophrenia (4). First-born children are documented to suffer hyperactivity more often than subsequent siblings (5). Perhaps parents treat the first-born with more attention and have developed better developmental skills for their other children. Later-born siblings are more often dominated by older ones.

As the birth order rises with more children, the chances for access to higher education might diminish due to limited family resources. As the number of children increases, the intellectual level of later ones sometimes declines: first-borns mentor younger ones, sometimes have higher intellectual capacity, and have more educational opportunities (6). Alternatively, some parents become more financially secure over time and better able to support education for later-born children (7).

First born children evidence less depression and/or anxiety than other later born ones and/or an only child; improved self-esteem is also evident (8). Perhaps this is due to the type of attention provided by parents just learning to provide for their progeny; later on, they gain expertise at nurturing, despite having less available time, being divided between more children. Emotional adjustment amongst some first born is less good as compared to others.

Children born in the midst of a sibship are documented with higher rates of lung cancer (9). This could be because later birth order children might be more exposed to secondhand smoke, but subsequent progeny often begin smoking at younger ages.

Different temperaments and sibling rivalry also are important.  First-born children are often more similar to their parents, while later ones more frequently resist authority and thus experience more noxious influences (10).

Birth order is a complex issue and varies with family size, socioeconomic status, and parental factors. Knowing a patient’s birth order provides information about home environments and may help to gauge the time parents potentially spend with children. Knowing about birth order and the number of siblings in patient-families is important when performing psychiatric evaluations.

References

1. “birth order.” net. STANDS4 LLC, 2019. <https://www.definitions.net/definition/birth+order.  Last accessed: March 26, 2020
2. Sulloway FJ. Born to Rebel: Birth Order, Family Dynamics, and Creative Lives. Pantheon/Vintage, New York. 1996.
3. MacDonald AP. Birth order and personality. Journal of Consulting and Clinical Psychology. 1971; 36(2): 171-176.
4. Lilliston L. Birth order and schizophrenia.  A short report. Schizophrenia Bulletin. 1970; 1(3):40-42.
5. Eaton W, Chipperfield J, Singbeil Birth order and activity level in children. Developmental Psychology. 1989; 25(4):668-672.
6. Zajonc RB, Marcus GB. Birth order and intellectual development. Psychological Review. 1975; 82(1):74-88.
7. Ejrnaes M, Portner C. Birth order and the intrahousehold allocation of time and education. The Review of Economics and Statistics. 2004; 86(4):1008-1009.
8. Gates L, Lineberger MR, Crockett J, Hubbard J. Birth order and its relationship to depression, anxiety, and self-concept test scores in children. The Journal of Genetic Psychology. 1988; 149(11):29-34.
9. Barclay K, Kolk M. Birth order and mortality: A population-based cohort study. Demography. 2015; 52(2):613-639.
10. Khalek A, Lester D. Sibship size, birth order, and personality. Psychological Reports. 2005; 97(2):387-388.