Medication
I would like to know what medications the co-pilot was taking. For instance, was the co-pilot trying to quit smoking? One of the published side effects of the anti-smoking drug Chantix is "Suicidal thoughts or actions" (Also stated is their television advertisements). Some of the modern anti-depressants, such as Prozac can cause people to become both homicidal and suicidal. My main source is my father, a Pharmacist with over 60 years experience dispensing psychotropic drugs. Unfortunately in this case individual "Privacy" may trump public health. When a mass murder happens here in the USA, even when the killer is a known paranoid schizophrenic, what medications they were taking at the time of the mass murder, are never published, because of privacy (or drug company lobbyists), so whatever medications involved escape the further scrutiny they deserve.