Post Natal Depression: Part II
How do mothers affect the development of emotional regulation in infants? Murray showed a film of a study with mothers and 14-month infants in which the mother is first asked not to interact with the child when the researcher puts a toy frustratingly out of reach. The child naturally becomes distressed and remains so. When the mother is allowed to support her child, she responds quickly with an empathic facial expression. Then she says, “Oooh, how do you feel? Perhaps we can do something!” while giving a hopeful and suggestive facial expression. The mother begins to occupy the child by playing a little game with her fingers so that it distracts the child from her frustration at not being able to get the toy. It is clear how this kind of interaction repeated over and over can support the child’s growing tolerance for frustrating experiences.
In another wonderful film, a (non-depressed) mother is giving a bath to a 15-month girl. The mother is washing her face, and the child is tolerating this relatively well, but when she tries to brush her teeth, the child objects forcefully. This child turns out to have a firey temperament with a low threshold for frustration, and the mother must take account of the temperamental characteristics of her baby. The mother pauses a bit. She has a little toy that squirts water and uses it to squirt water on the toy the baby is playing with, making a connection with her. The baby responds happily, and then the mother builds on this connection and focuses on what the baby is doing. Mother pretends to brush her own teeth. The baby smiles and lets the mother brush her teeth, then takes the tooth brush and tries to do it herself. Of course, depressed mothers have little tolerance for this step-by-step reciprocal play at bath time. They are more likely to either forcefully take the toothbrush and get the job done over the objections of the baby, or withdraw.
What are the mechanisms by which the early mother-child relationship affects the development of depression in the child? First there is emotional contagion (Field, 1984, 1988). There are also effects on the HPA axis (Murray et al, 2010 a). Finally, there is the link between insecure attachment and low resilience (Sroufe et al, 2005). One of my favorite studies, given my interest in vocal tones and non-symbolic communication, is one in which mothers were coded according to their speech tones (Murray, 2010). Falling intonation, non-rhythmicity, and monotony were significantly more prominent in PND mothers. In the non-depressed mothers, there was a rhythmic quality, with variability in pitch. What is the human equivalent of Michael Meaney’s “low licking mothers” whose babies had elevated cortisol levels? It is the low engagement of depressed human mothers. Halligan et al,, in 2004 and 2007) found that the 13-yo children of depressed mothers had elevated morning cortisol levels, which was predictive of depressed state. In one film of a 7-year old child of a PND mother playing a game with a peer, the child was initially triumphant when she was winning, but when she lost the advantage, she also lost her composure. Even when you control for marital conflict, maternal depression at the beginning of the infant’s life proves to be a predictor of depression at 16 years (Murray et al, 2011).
In conclusion, PND is associated with a range of disturbances in the mother-infant relationship. Babies’ outcome is affected in diverse domains- cognition, behavior, and affect, to name several important ones. Each outcome might have a specific developmental trajectory, such that for example, a depressed child may have no cognitive impairment. One of the most important take away points from this presentation is that obstetricians and pediatricians must get better and better at identifying and treating mothers with PND. Another point, though with less immediate importance, is for mental health clinicians learn to elicit the history of a PND in their evaluations of children with psychiatric problems. Finally, it is crucial to remember that nothing is written in stone. These problematic patterns may be interrupted at any point in the process – whether by the early intervention I have just been advocating, psychotherapy in the older child or adolescent, or by positive life events – a new supportive partner for the mother, the healing of an important relationship from the past, a better work situation, a new group of supportive friends for the child, the discovery of a talent in the child that brings positive self esteem to the whole family – that change the family trajectory in a better direction. Pointing out risk factors is never helpful without an equal emphasis on the resiliency factors that create a natural correction on a family life turning off course.
Murray L, Marwick H, & Arteche A, (2010). Sadness in mothers’ ‘baby-talk’ predicts affective disorder in adolescent offspring, Infant Behavior and Development, 33:361-364.
Murray L, Halligan S, Goodyer I, & Herbert J, (2010 a). Disturbances in early parenting of depressed mothers and cortisol secretion in offspring: A preliminary study, J Affective Disorders, 122:218-223.
Murray L, Arteche A, Fearon P, Halligan S, Goodyer, I, & Cooper P (2011). Maternal postnatal depression and the development of depression in offspring up to 16 years of age, J Amer Acad Child Adol Psychiat, 50(3):460-470.
Photo – Joshua Sparrow, M.D., Nov. 2012