Stress timing, trauma exposure, and family resilience differentially affect internalizing and externalizing symptoms at 3, 5, and 7 years of age.

Mental health disorders are associated with decreased quality of life, economic productivity loss, and increased mortality. The association between stressful experiences and psychopathology is well documented. However, studies are needed to understand the impact of timing of stressful events, types of traumatic experiences, and of family resilience on internalizing and externalizing symptoms in early childhood. The present study used a longitudinal design towards this end. Parents (N = 456) completed study measures at infancy, 2 years, 3 years, 5 years, and 7 years. At 3 years, greater stressful events during the prenatal period, 1-2 years, and 2-3 years (B = 0.833-0.369, p = 0.028-0.046) predicted internalizing symptoms for female participants only. For externalizing symptoms at 3 years, every time point assessed was significantly associated with more symptoms across both sexes (B = 1.071-0.414, p < 0.001). At 5 years, both internalizing and externalizing symptoms were associated with a greater number of stressful events at every time point and across sexes (B = 1.372-0.465, p < 0.001-0.002). There was evidence for timing effects, including cumulative effects, sensitive periods, and recency effects. Exposure to interpersonal trauma associated with greater internalizing symptoms (B = 2.120, p = 0.002), whereas both interpersonal (B = 1.879, p = 0.005) and non-interpersonal (B = 1.223, p = 0.032) traumatic experiences were associated with greater externalizing symptoms. Aspects of family resilience including higher levels of family commitment, ability to face challenges, and sense of control reduced risk for internalizing symptoms (B = -0.496, p = 0.004) while only greater sense of control (B = -0.838, p = 0.040) reduced risk for externalizing symptoms at age 7 years, including in the context of trauma.