research suggest that Folate, vitamins B are associated with depression:

http://www.ncbi.nlm.nih.gov/pubmed/15671130

http://altmedicine.about.com/od/treatmentsfromatod/a/FolateB12.htm

However, i believe some of those people in sajha who are saying their lives are lifeless or useless now or they have suicidal feelings are responding out of frustration, not because they are going through chronic depression. all of them will recover soon and they will find themselves very happy over time i hope.