I have been directed to this interesting site by Alison Blenkinsop, lactation consultant and midwife. http://homepage.ntlworld.com/blenky/alison5.html
Kathleen Kendall-Tackett is an American lactation consultant and researcher into postnatal depression. Her site is:-
There are some great links here to research articles linking postnatal depression and breastfeeding.
Also on her Postpartum Depression Home Page are two overview articles on postpartum depression. The first examines postpartum depression from a psychoneuroimmunology prospective.
* Kendall-Tackett, K. A. (2007). A new paradigm for depression in new mothers: The central role of inflammation and how breastfeeding and anti-inflammatory treatments protect maternal mental health. International Breastfeeding Journal, 2:6( http://www.internationalbreastfeedingjournal.com/content/2/1/6).
The second is a curriculum that provides an overview of depression, including assessment scales.
* New Hampshire Breastfeeding Task Force. A breastfeeding-friendly approach to depression in new mothers. 2009 Edition.