Autism & Developmental

Family history of psychiatric conditions and development of siblings of children with autism.

Bellia et al. (2024) · Autism research : official journal of the International Society for Autism Research 2024
★ The Verdict

Family history of mental illness predicts slower social, thinking, and daily-living growth in baby siblings of autistic children.

✓ Read this if BCBAs who screen or provide early intervention to infant or toddler siblings of autistic children.
✗ Skip if Practitioners who only serve adults or children with no family autism history.

01Research in Context

01

What this study did

Bellia et al. (2024) asked whether family mental-health history shapes how baby siblings of autistic children grow. They tracked social, thinking, and daily-living skills in these infants. Parents filled out forms about any family history of schizophrenia, depression, anxiety, bipolar disorder, or intellectual disability.

02

What they found

Babies with a family history of those conditions scored lower on social, thinking, and daily-living tests. The more psychiatric diagnoses in the family tree, the flatter the child’s growth curve. A positive history predicted worse outcomes even when the baby did not later receive an autism diagnosis.

03

How this fits with other research

Toth et al. (2007) first showed that toddler siblings of autistic children already talk, play, and adapt less well than typical peers. Giselle’s team now adds a clear reason: inherited psychiatric risk may drive much of that lag.

Lovell et al. (2016) and Koukouriki et al. (2021) found that school-age siblings feel more depressed when parents also report anxiety or low support. Giselle shifts the lens earlier, showing that family history starts shaping development in infancy, not just mood in childhood.

Maddox et al. (2015) and Wan et al. (2012) watched high-risk babies at 6–11 months and saw lower social spark during play. Giselle links that early social dip to family psychiatric load, giving a possible ‘why’ behind the quiet interactions.

04

Why it matters

When you assess an infant sibling, add a quick family psychiatric screen. Ask about schizophrenia, depression, anxiety, bipolar, and ID in parents, grandparents, and aunts/uncles. If any are present, plan tighter developmental check-ups and start early play, language, or parent-coaching services sooner. You can’t change genes, but you can change timing and intensity of support.

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Add one page to your intake packet that asks about family history of schizophrenia, depression, anxiety, bipolar disorder, and ID, then flag positive cases for monthly developmental monitoring.

02At a glance

Intervention
not applicable
Design
other
Sample size
229
Population
autism spectrum disorder
Finding
negative

03Original abstract

Younger siblings (SIBS) of children with autism exhibit a wide range of clinical and subclinical symptoms including social, cognitive, language, and adaptive functioning delays. Identifying factors linked with this phenotypic heterogeneity is essential for improving understanding of the underlying biology of the heterogenous outcomes and for early identification of the most vulnerable SIBS. Prevalence of neurodevelopmental (NDD) and neuropsychiatric disorders (NPD) is significantly elevated in families of children with autism. It remains unknown, however, if the family history associates with the developmental outcomes among the SIBS. We quantified history of the NDDs and NPDs commonly reported in families of children with autism using a parent interview and assessed autism symptoms, verbal, nonverbal, and adaptive skills in a sample of 229 SIBS. Multiple regression analyses were used to examine links between family history and phenotypic outcomes, whereas controlling for birth year, age, sex, demographics, and parental education. Results suggest that family history of schizophrenia, depression, anxiety, bipolar disorder, and intellectual disability associate robustly with dimensional measures of social affect, verbal and nonverbal IQ, and adaptive functioning in the SIBS. Considering family history of these disorders may improve efforts to predict long-term outcomes in younger siblings of children with autism and inform about familial factors contributing to high phenotypic heterogenetity in this cohort.

Autism research : official journal of the International Society for Autism Research, 2024 · doi:10.3389/fpsyg.2012.00111