A psychiatric evidence seems to have decided that the criminals in the murder cases with cannibalism in Brazil were mentally normal.
Surgiu: "Canibais" de Garanhuns não têm distúrbios mentais (in Portuguese)
The criminals were arrested in the town of Garanhunsin in April 2012 for murdering multiple persons and eating their fresh. Over one year after the arrest, they are proven to be legally responsible.
BBC: Brazil murder suspects 'confess to cannibalism'
I dare not to give any comments about this case, since I can hardly understand the essence of a case based on public news. I do not know whether the result of the investigation is rational.
Actually, it is quite difficult to determine whether a behavior strongly bound to a certain culture is pathological or not. Cannibalism is never accepted at least in developed countries. However, it was common in some ancient cultures. Some cultural or religious ideologies are hard for us to be distinguished from delusion.
A Norway massacre case occurred in 2011 also brought about wide discussion. The conclusions of two different psychiatric examinations differed from each other. Finally the criminal was sentenced 21 years imprisonment as a sane defendant. I wonder how to interpret his warped thoughts.
Culture and Thoughts will alter through the time. It makes the issue more complicated. It is possible that a certain idea extremely usual at now would be deemed as insane in the future.