Postnatal depression (PND) is the most common psychological disorder to affect women in the postpartum period, with an estimated prevalence of 13% in high-income countries (Gavin et al. 2005; O’Hara and Swain 1996). In low and middle income countries, the available evidence suggests that rates of PND may be substantially higher, with prevalence estimates ranging from 15 to 57% (Wachs et al. 2009). In terms of clinical presentation, depression occurring in the postnatal period appears to be indistinguishable from depression occurring at other times (Cooper et al., 2007), with persistent low mood and/or a profound loss of interest and enjoyment being defining characteristics. Other symptoms are mood-related disturbances in sleep, altered appetite, concentration impairment, retardation, agitation, feelings of guilt and hopelessness, and suicidal thoughts or impulses. The duration of episodes varies, but the majority of postpartum depressive episodes resolve spontaneously within 6 months to a year (Cooper and Murray 1995; Cox et al. 1993). Although PND may not be unique in terms of the symptom profile, the fact that this disorder occurs in the postpartum period is a particular concern. Specifically, PND affects the mother–infant dyad at a time when the infant is particularly reliant on his or her caregiver to meet their physical, social, and cognitive needs. The postpartum period is also a time when the family unit as a whole is likely to experience additional stress, and is therefore particularly vulnerable. Given these considerations, and the relatively high prevalence of PND, the potential for adverse impact is significant. One area of research focus, reviewed here, has examined the possibility the disturbances in the mother–child relationship occurring in the context of maternal PND result in fundamental alterations in key psychobiological systems in the infant, with persistent consequences. Notably, as PND typically resolves within the first year postpartum, and therefore is particularly relevant to early development, observations deriving from the study of PND in this area offer potentially broad insights into the relevance of early environmental factors to child neurobiological functioning. Given that depressive disorder is characterized by profound impairments in mood, energy levels, motivation, and feelings of self-worth, and has established detrimental effects on interpersonal functioning, it is perhaps unsurprising that mothers with PND have been found to show disturbances in the quality of care that they provide for their infant (for a review, see Murray et al. 2010a).
An exploratory study of the ways in which mothers keep their infants occupied
