Neural dysfunction in postpartum depression: an fMRI pilot study

With approximately 4 million births each year in the United States, an estimated 760,000 women annually suffer from a clinically significant postpartum depressive illness. Yet even though the relationship between psychiatric disorders and the postpartum period has been documented since the time of Hippocrates, fewer than half of all these cases are recognized.

Because postpartum depression (PPD), the most common complication of childbearing, remains poorly characterized, and its etiology remains unclear, we attempted to address a critical gap in the mechanistic understanding of PPD by probing its systems-level neuropathophysiology, in the context of a specific neurobiological model of fronto-limbic-striatal function.

Using emotionally valenced word probes, with linguistic semantic specificity within an integrated functional magnetic resonance imaging (fMRI) protocol, we investigated emotional processing, behavioral regulation, and their interaction (functions of clinical relevance to PPD), in the context of fronto-limbic-striatal function.

We observed attenuated activity in posterior orbitofrontal cortex for negative versus neutral stimuli with greater PPD symptomatology, increased amygdala activity in response to negative words in those without PPD symptomotology, and attenuated striatum activation to positive word conditions with greater PPD symptomotology.

Identifying the functional neuroanatomical profile of brain systems involved in the regulation of emotion and behavior in the postpartum period will not only assist in determining whether the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition psychiatric diagnostic specifier of PPD has an associated, unique, functional neuroanatomical profile, but a neurobiological characterization in relation to asymptomatic (postpartum non-depressed) control subjects, will also increase our understanding of the affective disorder spectrum, shed additional light on the possible mechanism(s) responsible for PPD and provide a necessary foundation for the development of more targeted, biologically based diagnostic and therapeutic strategies for PPD.