First, I think that before you can help anyone depressed they have to come to you for help. Then I think that depressed thinking often arises due to disharmony

First, I think that before you can help anyone depressed they have to come to you for help. Then I think that depressed thinking often arises due to disharmony within the body, so that although the symptoms of depression are often found in someone's thinking, no cure can be found for depression in addressing the issues that seem to be at stake. Depression is not usually caused by any historical experiences no matter how terrible and is not caused by a "bad attitude". Because depression has so many potential somatic causes, there can be no generally effective treatment for depression. Certain drugs are touted as achieving good results, using certain measures, but nobody takes those drugs and is thereby healed. I believe that the best (or only!) things I can do for depressed friends are 1) to explain to them that depression is not their fault and 2) to support them by letting them be a part of my life.