Grant: Operating Grant - Priority Announcement: Institute of Gender and Health

Postpartum depression can affect 15% of women. Postpartum depression is debilitating to both the mother and her children. The cause of postpartum depression is not known, but there are large fluctuations in hormones during pregnancy and postpartum. Hormones, in turn, appear to be involved in depression. One particular hormone cortisol (the stress hormone) is involved in depression and there are high sustained levels of cortisol during the latter half of pregnancy and into the postpartum. In this proposal, we will investigate the effects of a model of postpartum depression, one that we have developed that mimics the high levels of cortisol that are present both during pregnancy and the postpartum period. We will investigate how this model of PPD affects both behaviour and measures of cell growth in two brain regions known to be implicated in depression: the hippocampus and the prefrontal cortex. Depressed patients tend to have a smaller hippocampus and have decreased activity in the prefrontal cortex. Intriguingly, the hippocampus maintains the ability to produce new cells in adulthood, unlike many other brain regions. In the past, neurogenesis in the hippocampus has been linked to depression. We will investigate the effects of this model on depressive-like behaviours, reactivity to stress (which is altered in depressed patients) and the change in brain cell structure in both the mother and her adolescent and adult offspring. We will also examine the effects of pharmacological and physical antidepressants to reverse any adverse changes we see in the mother and her male and female offspring. It is vitally important to test the effects of this model and treatment in the offspring of 'depressed' mothers as maternal depression can severely impact the emotional, cognitive well-being of children. We hope that these studies will bring us closer to understanding the mechanisms and possible treatments for postpartum depression.