The author is a nun (daughter of St Paul - which might explain the FSP credentials) and has written this book from her own experience battling depression. It is not meant to be a medical book, rather it is focused on creating a holistic approach to treatment (therapy, medications and above all, prayer).
By googling her name, I found several other of her books endorsed and published by several reputable Catholic sources. If the book has an imprimatur, it would be stamped inside the copyright page.
There is an article about the author and book here:
http://www.cst-phl.com/040408/leisure.html
Daughter of St. Paul Sister Kathryn J. Hermes was a young Sister of 21 when she experienced a devastating stroke, which caused severe memory loss and partial paralysis which were overcome only after a lengthy period of rehabilitation.
A more insidious effect which she did not confront for years was deep, chronic depression. In her book, “Surviving Depression: A Catholic Approach” (Pauline Books and Media, Boston 145 pp. $11.95), Sister Kathryn tells how she first tried to accept her stroke and its aftereffects as the will of God.
It took six years before she realized how angry she was — angry with God, angry with those around her, angry with the world.
“As the cycle of depressions came and went, with confusion and despair clouding my vision, I wrestled with God, trying to understand just one question, ‘Why me?’” she writes.
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Once severe depression is realized, Sister Kathryn stresses, the victim should seek appropriate attention, including prescribed medication and therapy.
But for the Christian, prayer should be part of the road to recovery. She does not claim medical or psychiatric expertise, but rather speaks from the viewpoint of a sufferer of depression for whom faith has played a large role in keeping it under control.