From BBC on-line:
When Mr Lubitz finished training in 2009, he was diagnosed with a serious depressive episode and went on to receive treatment for a year and a half, the German news site Bild reports.
Internal documents quoted by Bild and German broadcaster ARD say a note on Mr Lubitz's aviation authority file recommended regular psychological assessment.
I would just add that Germany has rather strict privacy laws and release of this information is ilegal