Going with what is known so far....
My personal opinion is that he is on the autism spectrum - more like the Asperger's form than regular autism even though that dx has been removed from DSM-V. That is the foundation of his problems. Layered on top of that are a depressive disorder with psychotic features. In addition, he is very intelligent, which can cause additional problems.
Assuming that I basically have that right, his decision to commit a mass murder, although a highly statistically unlikely thing for someone to do, does not entirely surprise me, for these reasons:
- people on the autism spectrum often have problems with depression, anxiety, ADHD, etc. It is nothing out of the ordinary for someone on the spectrum to also have these problems. So he is not unusual in that regard - to be on the spectrum and then to also have a mood disorder
- as people on the spectrum grow in age, they slowly become more aware of how different they are from others. It is very normal that JH, as he got into his late teens/early 20's, would begin to feel increasingly socially isolated as his peers' social skills and developmental levels exceeded his. This social isolation and inability to make and keep friendships and romantic relationships would cause him to feel frustrated and helpless.
- an additional difficulty for JH is that he is very intelligent; this reduces the number of people who he will feel he can truly relate to/connect with on an intellectual level. Even if he had none of the other problems, this issue alone could cause him some difficulties
- neuroscience was a major part of his life - not only as an intellectual interest (something that would be very important for an intelligent person on the autism spectrum), but also as an area where he could succeed (unlike the social side of his life); I think that his burgeoning awareness that he was not succeeding in graduate school the way his peers were was a major contributing factor to his depression
- I believe he had a loss of a relationship with a girl prior to the shooting; this would be another major trigger for feelings of isolation, rejection, failure, and perhaps rage as a result of those painful feelings
- as depression develops and deepens, the hopelessness, feelings of being disconnected from others, obsessive thoughts about being rejected/hurt, anger, and wanting relief from these thoughts and feelings increase.
- males are more likely to externalize their anger, so projecting his hate out onto others, and obsessing about violence, rather than committing suicide doesn't surprise me
As I learn more about JH, I see many parallels to Elliott Rodgers. ER was more fixated on not having relationships than JH appears to be, but in terms of being on the spectrum and having severe depression, and then choosing mass murder to cope with those feelings, they are very similar.
I also see some parallels to Seung-Hui Cho (Virginia Tech mass murderer).
Again just my preliminary humble opinion
