Hi Philipp,
For immediate relief from depression check out this article:
Breaking the Spell of Depression
For long-term, non-medicated permanent relief from depression check out this whitepaper:
http://www.nickpagan.com/blog/wp-con...fectly-v10.pdf
What you'll find there is basically cognitive therapy taken a step further by understanding very thoroughly what causes severe negative emotions in the first place and how to eliminate them completely.
Let me know if you require further explanation on anything.
Take care,
Nick