Longitudinal Associations Between Maternal Withdrawal in Infancy and Adult Hippocampal Volume and Suicidal Behavior

• In Event: 2-025 - Attachment and Caregiving Dysregulation: Neural Correlates, Sequelae, and an Effective Intervention

Integrative Statement

Introduction: Adverse childhood experiences have been linked to altered hippocampal volume in clinical and community samples. However, the direction of effect varies depending on the age of the sample and the type of early life stress (Maheu et al., 2010; Mehta et al., 2009; Teicher & Samson, 2016; Tupler & De Bellis, 2006; Whittle et al., 2013). Research also suggests that hippocampal alterations are associated with the development of mental health problems, particularly suicidality. Epigenetic modifications were found in the hippocampus of suicide victims who experienced childhood abuse (McGowan et al., 2009). Research to date has not prospectively examined disruptions in maternal care in association with hippocampal development, but prior work found a link between early maternal withdrawal and suicidal behavior (Lyons-Ruth et al., 2013). In the context of a 30-year longitudinal study, we assessed disruptions in maternal communication in infancy in relation to both hippocampal volume and suicidality/self-injury in adulthood.

Hypotheses: 1) We hypothesized that disrupted maternal behavior in infancy would prospectively predict adult hippocampal volume. However, given the inconsistencies in the literature, the direction of predicted hippocampal volume was unclear. 2) We predicted that hippocampal volume would be associated with greater levels of suicidality/self-injury. 3) Finally, we assessed whether hippocampal volume mediated the relation between early disrupted maternal behavior and suicidality/self-injury in adulthood.

Methods: 18 individuals (44% male) were part of a larger cohort followed from infancy to adulthood. In infancy (18.58 ± 1.02 months), disrupted maternal communication was assessed using the Atypical Maternal Behavior Instrument for Assessment and Classification (AMBIANCE). Five classes of disrupted maternal communication were coded. In adulthood (29.33 ± 0.49 years), MRI procedures were conducted to assess total grey matter volume and gray matter volume in the hippocampus, caudate and thalamus. The Structured Clinical Interview for DSM-IV-R (SCID; First et al., 1997) for Axis II was used to assess the presence of recurrent suicidality/ self-injury.

Results: Correlation analyses were conducted in SPSS 24 and mediation analyses with bootstrapping were conducted in Mplus 8. As shown in Table 1, there were significant correlations between maternal withdrawal, left hippocampal volume, and suicidal/self-injurious behavior. Maternal withdrawal predicted left hippocampal volume (beta= .58, SE= .31, CI [.14, .94]), left hippocampal volume predicted suicidal behavior (beta= .36, SE= .15, CI [.12, .63]), withdrawal predicted suicidal behavior (beta= .71, SE= .16, CI [.36, .89]), and left hippocampal volume partially mediated the relation between withdrawal and suicidal behavior (beta= .21, SE= .19, CI [.06, .58]; Figure 1).

Conclusions: Results indicate that early maternal withdrawal predicts suicidal behavior through enlarged left hippocampal volume. We have suggested that early maternal withdrawal may elicit a pattern of ‘seek and squeak’ or enhanced attempts by the infant to seek proximity and contact with mother. This elicited behavioral adaptation may lead to an enlarged hippocampus rather than hippocampal reduction. The findings suggest that the first two years of life may be a sensitive period for hippocampal development, which may have long lasting implications for stress regulation and mental health.

 

Authors

• Jennifer Khoury, Harvard Medical School, Cambridge Hospital
  Presenting Author

• Martin Teicher, Harvard Medical School
  Non-Presenting Author

• Pia Pechtel, University of Exeter
  Non-Presenting Author

• Carl Anderson, Harvard Medical School
  Non-Presenting Author

• Karlen Lyons-Ruth, Cambridge Health Alliance and Harvard Medical School
  Non-Presenting Author