I have had a little experience of people ill with depression. Rather like cancer there are many different types and different severities. Some depressions grow slowly, others are quick, sudden and aggressive. Some sufferers are able to maintain a level of rational thought, others are not and behave totally out of character from their 'well' selves. Some will recover fully and go on to live useful and purposeful lives, some depression sufferers may not.
For those on here who are so quick to judge the co-pilot who may have been too sick to realise the enormity of his actions I would say you are lucky not to have someone you love and care about suffering from crippling depression.
I am saddened by the horrific loss of life and the dreadful damage to so many families who have lost their beloved relatives and friends.
However I will reserve my opinion about the co-pilot being too ill to be considered 'evil', until there is more information (facts, not homespun theories!). It does seem beyond doubt his actions were directly responsible for this tragedy.