Post published on Bluesky on 14 Jul 2025 10:42

Abstract

Background There is a pressing need for research on neurodevelopmental conditions to focus on predictors of resilient or positive outcomes, rather than core symptoms and impairment. One promising avenue is to consider whether child–parent similarity contributes to a protective family environment. For instance, investigations of the similarity–fit hypothesis have shown that parent–child attention‐deficit/hyperactivity disorder (ADHD) trait similarity is associated with more favourable parent or child ratings of parenting and parent–child interaction. However, very little similarity–fit research has focused on autism, and none to date has investigated whether parent–child trait similarity is more broadly predictive of children's outcomes beyond parent–child interaction. We assessed whether parent–child autism and ADHD trait similarity predicted children's social functioning and psychological well‐being in early childhood in a family history cohort. Methods Our analytic sample comprised 222 children (45.5% female) and their parents from a longitudinal family history (autism and/or ADHD) cohort. A novel parent–child trait similarity measure was computed for autism and ADHD traits in each parent–child pair, and robust hierarchical regression was used to assess whether mother–child and father–child autism and ADHD similarity predicted children's social functioning and psychological well‐being at age 3 years, after accounting for the main effects of parent and child traits. Results Mother–child autism trait similarity positively predicted both social functioning and psychological well‐being in children, while mother–child ADHD trait similarity positively predicted children's social functioning (but not well‐being). Furthermore, father–child autism trait similarity positively predicted children's social functioning, though it fell just short of statistical significance in outlier‐robust regression. Conclusions Our findings suggest that parent–child neurodevelopmental trait similarity may act as a protective or promotive factor for children's early social functioning and psychological well‐being. Further work is warranted to determine whether there are similar effects in later childhood and to investigate the potential mechanisms underlying similarity–fit effects on children's outcomes.