Friendships play an important role in shaping children’s developmental outcomes. For instance, research has shown that children who have friends and those have no friend differ in various aspects, such as peer group status and academic performance. Chen, along with collaborators, conducted a one-year longitudinal study using an action-partner interdependence model (APIM) to explore the role of friendship in the development of academic achievement and depression for same-domain as well as cross-domain effects, i.e., the associations between academic performance and depression in one member of a friendship dyad and later the academic performance and level of depression of the partner member.

Academic achievement and depression are considered as two domains, thus, an association between antecedent academic results and later academic achievement indicates same-domain effect, while cross-domain refers to an association between academic achievement and depression. The effect within the same individual from Time 1 (T1) to Time 2 (T2) is described as actor effect, and the effect between dyads (two children) is partner effect.

The sample used was 1122 grade 4 and grade 5 students (494 boys) with 561 same sex dyads identified as stable friendships from 61 classes in 5 public elementary schools in Southeast China based on children’s best friends nomination in a two-wave data collection. Students’ academic achievement was an index formed by mean exam scores of Chinese, mathematics, and English adjusted with teacher-rated scores of learning problem. Students’ depression was assessed using the self-reported Childhood Depression Inventory. After controlling for gender, grade, and interdependence between friend dyad members (i.e., all possible same-domain and cross-domain effects of both actor and partners are included in the same analysis model), the results were as follows:

• A cross-domain actor negative effect of depression on academic performance was found (β =-0.10), i.e., the higher T1 depression the lower T2 academic achievement within same child. However, the reverse effect was not found.
• A same-domain partner positive effect was found for academic performance (β = +0.14) but not for depression (β =-0.01).
• A cross-domain partner negative effect was found for T1 academic performance on T2 depression (β =-0.10). In other words, students with an academically better friend had a low level of depression a year later. But a partner effect of T1 depression on T2 academic performance was not found.

The findings suggested that children who had academically competent friends were likely to benefit from the relationship during the development stage for strengthening their academic performance and for reducing their feelings of depression.

Source: Chen, X., Zhou, J., Liu, J., Li, D., & Liu, S. (2022). Academic performance and depression in Chinese children: Same-domain and cross-domain effects in friendships. Child Development, 00, 1–15. https://doi.org/10.1111/cdev.13864