Why is it so hard to talk about depression/mental health with some of my African friends?

The word depression or mental health is very cautiously mentioned in conversations with many Africans. Many Africans believe that it is not an 'African illness'. Just the mere mention of the 'D' word, brings shocked looks and telling off from 'concerened individuals'. I am talking about this because it is a concern voiced by many Africans I have met. A friend was sharing with me how she is suffering from post natal depression and how she found it difficult speaking to family and friends about her depression. Each time she mentions it to anyone she knows, they tell her off. They tell her she is not suffering from depression, she should reject depression and learn to speak positively. I volunteer in a charity organisation where we deal with people who are in despair or distressed. It is very difficult opening up to anyone about depression but it sure helps.

One thing I observed is that it is so hard trying to open up to friends and relatives. Another friend mentioned that once one mentions how down one feels, they get a telling off and asked to count their blessings. They get the whole lecture of not being grateful, how others are worse off etc. Surely, there should be an awareness that depression is a mental illness and not something one wishes on ones self? I believe that many Africans should be open minded that Africans also suffer from depression and find ways to highlight this issue and provide help.