One of the reasons why it is so difficult to cure depression is that it is not quite clear what causes it. However, a few causes that quite often lead to depression have been singled out by doctors and researchers.
The first cause to mention is sexual, physical or emotional abuse. It is quite clear why it has such a huge impact on a person as it is a horrible and even traumatic experience. Some people become depressed after the death of a loved one as it seems impossible to deal with all grief. Another cause is genetics. A family history of depression increases the risk of suffering from it which is the reason why it is so important to be aware of that.
A lot of personal issues might lead to depression. A person who has anxiety issues might suffer depression as well. Apart from that, a lot of people with substance abuse problems tend to have clinical depression. Yet, what is important here is to be able to seek and provide help when either you or one of your loved ones experience depression.