The herb St.John's wort is effective against depression because it is believed to increase serotonin.
One aspect of depression that is corrected in me, I suffer with depression, is turning off a negative decision making cycle. This cycle makes it difficult to make good decision about life. So, depression involves not only a depressed mood but also the ability to make appropriate decision.

The poor decision making ability leads to situations that are maladaptive and sometimes life threatening.
1.Difficulty discerning people who are destructive or recognizing the destructive element in ones own being.
2.Impulsive decisions that are fun in short run but later are revealed to be destructive.
3.Difficulty trusting so one choose people who are superficial but fun.
4.Timidity and withdrawal from social situations that require a give and take exchange. But justified by believing people are against one.
5.Perceiving challenging social situations as threatening.
6.Rejection of mental and physical health help.