Trajectories of internalizing symptoms in early childhood: Associations with maternal internalizing symptoms and child physiology.

Research has shown that children's internalizing symptom development during early childhood are shaped by biopsychosocial processes including physiology and parental symptoms. However, associations between maternal internalizing symptoms, child physiology and trajectories of child internalizing symptoms are not well understood. We used growth curve models to examine how maternal internalizing symptoms, child physiology and the interaction between maternal internalizing symptoms and child physiology may be associated with trajectories of internalizing symptoms during early childhood. Mothers reported their children's internalizing symptoms when children were 3, 4, 5 and 6 years of age, and mothers self-reported their own internalizing symptoms when children were 3. Respiratory Sinus Arrhythmia (RSA) was collected when children were 3.5-years-old. Results showed that there is a non-linear, quadratic trajectory across all participants from age 3 to 6. Maternal internalizing symptoms were not associated with children's internalizing symptoms at age 6, but were associated with both linear and quadratic change. Lower resting RSA was associated with greater increases in children's internalizing symptoms over time. Interactions between maternal internalizing symptoms and RSA were not associated with children's internalizing symptom development. The findings demonstrate that maternal internalizing symptoms and child physiology are independently associated with internalizing symptom development during early childhood.