Call me cynical, but any time a person near to power "commits suicide" or otherwise recuses themselves from the scene (present or historically), I generally take their volition in the matter with a very large grain of salt.
Vincent Brown The Reaper's Garden is a great guide to diasporic African folkways surrounding death in the early modern period. He argues that enslaved Africans mobilized their social practices surrounding death as a way of asserting a kind of underground political power in plantation societies. At any rate, you won't find many people studying the history of the Atlantic slave trade or colonial Africa who think that people were coping adequately with the situation. The debate is more about whether it was so shatteringly destructive that it led to a total "social death" or whether some elements of culture and personhood were able to survive. I am in the second camp. But like I said, people were deeply psychologically and often physically scarred in this period.
Just curious, earlier you stated that you spent "a lot of [your] mental life in the 17th century", where does that reach extend to? Is it just Portugal or is it specific to the Atlantic Slave Trade?
I work on early modern Britain, Portugal, and their colonies.