I think I have got postnatal depression. My daughter is five weeks old and exclusively breastfed. My GP will not prescribe any medication unless I give up breastfeeding.
Seven years ago I had postnatal depression and a different GP prescribed sertaline. I was breastfeeding at the time and there is no evidence that taking sertaline hurt my son in any way.
Infact I think he benefitted from having a healthier mummy. He is a bright and healthy seven year old.
I found sertaline extremely effective and I was off all medication after 18 months. I did try councelling, but I found it a waste of time. For bio chemical depression anti depressant are effective. I have no deep seated issues in my life, it is just that my hormones are playing hell.
I accept that taking anti depressants and breastfeeding is not ideal. However formula milk is not 100% safe either. It is also bad for a baby to have a mummy with untreated depression.