Longitudinal evaluation of the Family Stress Model in families of children with intellectual disabilities

The Family Stress Model (FSM) is a developmental framework used to explain the relationship between family economic hardship and children’s developmental outcomes through parent factors. As a developmental theory, the FSM should be able to explain the impact of early adversity on developmental outcomes for all children, including children with intellectual disabilities. Primary caregivers ( n = 372, 88 % White British) of children with intellectual disabilities ( M age at Wave 1=7.31 years, SD =1.91) completed an online survey at three time points. The survey measured subjective and objective poverty, parental psychological distress, parenting behaviours, child-parent relationship quality, and the developmental outcomes of the child with intellectual disabilities. A series of preregistered structural equation models were used to examine whether the FSM was applicable to a sample of families with children with intellectual disabilities. The final model testing the FSM using dimensions of child-parent relationship quality and parenting behaviours whilst covarying parenting and relationship variables had satisfactory model fit ( χ 2 (25)= 69.839; p < .001; CFI= .949; TLI= .887; SMSR= .055; RMSEA= .069, AIC= 18444.623). Child-parent relationship quality had a stronger effect on children’s developmental outcomes compared to the primary caregiver’s parenting behaviours. The FSM can be successfully applied as a developmental framework to families of children with intellectual disabilities. Reducing family economic adversity and parental psychological distress through early interventions and supportive social policy could significantly improve child-parent relationship quality, thereby improving developmental outcomes over time for children with intellectual disabilities. Future research studies should aim to test whether other theoretical models hold up when applied to this population. • The Family Stress Model was tested in families of children with intellectual disability. • Findings support the model as an applicable developmental theory for this sample. • Economic adversity impacts outcomes through child-parent relationship quality. • Results highlight early intervention points to reduce effects of economic adversity.