The role of infant sleep in intergenerational transmission of trauma

Abstract

Introduction: Children of parents who experienced trauma often present emotional and behavioral problems, a phenomenon named inter-generational transmission of trauma (IGTT). Combined with antenatal factors, parenting and the home environment contribute to the development and maintenance of sleep problems in children. In turn, infant sleep difficulty predicts behavioral and emotional problems later in life. The aim of this study was to investigate whether infant sleep problems predict early behavioral problems indicative of IGTT.

Methods: 184 first-time mothers (ages 18-47) participated. N=83 had a history of childhood abuse and posttraumatic stress disorder (PTSD+); 38 women reported childhood abuse but did not meet diagnostic criteria for PTSD (PTSD-); and the control group (N=63) had neither a history of abuse nor psychopathology (CON). Depression, anxiety, and sleep difficulty were assessed in the mothers at 4 months postpartum. Infant sleep was assessed using the Child Behavior Sleep Questionnaire (CSHQ). Outcome measures included the Parent Bonding Questionnaire (PBQ) at 4 months and the Child Behavior Check List (CBCL) at 18 months.

Results: Infants of PTSD+ mothers scored higher on the CSHQ and had more separation anxiety around bedtime than PTSD- and CON, and the severity of their symptoms was correlated with the degree of sleep disturbance. Maternal postpartum depression symptoms mediated impaired mother-infant bonding, while infant sleep disturbance contributed independently to impaired bonding. Mother-infant bonding at 4 months predicted more behavioral problems at 18 months.

Conclusions: Infant sleep difficulties and maternal mood play independent roles in infant-mother bonding disturbance, which in turn predicts behavioral problems at 18 months.

Keywords: Child abuse; PTSD; depression; development.

Figure 1

Estimated marginal means derived from multivariate ANOVA comparing male and female infants from the PTSD+, PTSD−, and CON. (A-D) Bed Time, Wakeup Time, Number of Nightly Awakening (#Wake), Wake After Sleep Onset (WASO). There were no main effects or interactions.

Figure 2

Estimated marginal means derived from multivariate ANOVA comparing male and female infants from the PTSD+, PTSD−, and CON on the total score of the CSHQ, and the two derived factors. (A) Sum CSHQ: PTSD+ scored higher than CON, independent of gender. (B) Sleep Anxiety: There was a main effect of cohort, due to higher score in PTSD+ females compared with CON. (C) Sleep Resist: There were no mains effects of cohort or gender. ‘♦’ denotes main effect of cohort.

Figure 3

Schematic of the model of the role of WASO and mothers symptoms in the development IGTT. Depression symptoms mediated the relationship between PTSD diagnosis and PBQ. WASO was correlated with mothers' mood and anxiety symptoms. WASO contributed independently (i.e., did not interact or mediate) to the variance in PBQ. PBQ, predicted degree of externalizing behaviors at 18 months. Thicker arrows denote a larger correlation or β coefficients. Numbers are βs derived from regression analyses.

Figure 4

Scatter plot of the correlation between PBQ at 4 mo (abscissa) and externalizing behaviors at 18 mo (ordinate), separated by gender. Gray circles for girls (R = 0.562, P = 0.001), white triangles for boys (R² = 0.268, P = 0.082).