No one really knows why postnatal depression affects some the way it does. Environment may contribute, there may be some interplay between hormones and environment, some have hinted at a genetic component, pointing to some increased probability if other members of the family have suffered from it, but the evidence is speculative and anecdotal. Other factors, such as transgenerational cycles of trauma, seem key to me. The experience of depression as a newborn will be carried through into adulthood and these feelings, if left unchecked will be re-enacted (in some way) with their own children as well as in their lives and relationships more generally. A seemingly normal and excited mother to be, could be taken by surprise with how she feels after having her baby. If, as a baby, she felt overwhelmed, anxious, sad and unloveable, these deeply repressed feelings can be triggered by such a profound experience particularly as she may not have had a good enough experience from which to learn and understand from and the old feelings of helplessness can re-emerge.
Developmental psychologists suggest that babies are profoundly sensitive to their mother’s facial expressions. Furthermore, the mother then mirrors the baby, she externalizes to the infant his sense of self, his identity. On one level, I suppose it is quite simple, a baby needs to have enough experience of being loved to enable him to trust the external world and to grow internally.
A depressed mother is typically less responsive to her infant’s emotional demands. She does not mirror her baby in the right sorts of ways and this can lead to a depressive child. The effects of postnatal depression then, even after it has passed, may be far reaching indeed. Motherhood, for some, stirs up these repressed feelings, initiating a process in which depression is passed onto the next generation in some infernal loop.
I have discussed a critical experiment before which reveals just how important the mothers subtle way of relating (i.e. her facial expressions) is to the baby. In the ‘still face situation’ the mother, after interacting normally with the baby, suddenly adopts a mask like still face (this particular mother only does this once and only for two minutes). Time and time again, the experiment reveals the baby attempting to move mother out of this posture (by smiling, pointing, screaming, crying) but when unsuccessful is dramatically distressed and ultimately becomes emotionally detached. The mother and baby dyad is all about timing, tracking and matching of vocal expressions, facial expressions and gaze. You can imagine what happens to the baby when a mother is too depressed to be in the baby’s world and completely attuned to it. The baby becomes deeply traumatized and terrified and shuts down emotionally – mirroring mum but also as an act of self-protection which unfortunately will have grave and serious repercussions later in life.