@FOUND SOUL,
I think you're on the right track with affluenza, Foundy, but Elliot went way beyond that.
He had a BMW, a more expensive car than many college men have, but he dreamed of winning the lottery and driving onto the campus in a Lamborghini, because that was more impressive. Nothing he did have was ever quite satisfying enough. He was always jealous of anyone who had more.
He never felt he had enough of
anything he desired, he was like a bottomless pit of envy--particularly when it came to great wealth and the lifestyle that can buy. And growing up in Hollywood, he was exposed to that kind of opulent lifestyle, and he could enjoy a taste of it, and a glimpse of it, and it very much shaped his values and his sense of entitlement.
He wanted his mother to marry a very wealthy man she had been dating, not for her happiness because she loved the man, but because of the lifestyle it would afford
him if she married that man
and his money--and he considered her selfish when she didn't do that. He wanted his mother to be a gold-digger--for his sake--and he was angry when she didn't accommodate him.
And having a hot beautiful blond girlfriend was viewed as a form of social wealth by him--a valuable trophy and a conquest to show off to establish his status with other men. In his mind beautiful hot blond women were like material possessions. And, he only wanted the top-of-the-line in terms of his possessions and surroundings. He really didn't see these hot beautiful blonds as
people--they were commodities to satisfy and gratify his needs and fantasies and establish his status in the world. Not much different than his several hundred dollar Armani sweaters.
He was constantly in a state of envy about one thing or another. That led to frustration, that to depression, and then that led to rage about the injustice done to him by such deprivation. There was a reality basis for his feeling that he didn't fit in socially, that he couldn't compete socially, and that he couldn't cope emotionally, and it really led to profound despair and hopelessness about his entire future. And his parents shared those concerns about his future and whether he would be able to function as an independent adult.
Someone else going through that sort of despair might just commit suicide. And, while he thought about that, he was ambivalent about it, he feared death, he really didn't want to die. So, he'd latch onto things--like the fantasy of winning the lottery and gaining instant great wealth--to keep a spark of hope going that his life would improve, that he'd get the things he wanted. When he became fixated with revenge fantasies, he could see his death in the context of a victory rather than a defeat. And, when he realized it might be possible to actualize his revenge fantasies, and he bought his first gun, that gave him a real sense of power, and brought about a shift in his thinking that was his final undoing. Being able to acquire a gun made a real emotional difference for him--it made his fantasies possible.
Reading the last portion of his manifesto was like watching him psychologically paint himself into a corner, a smaller and smaller corner, until he finally trapped himself into needing to carry out his Day of Retribution to prove to himself and the world he wasn't an unmanly coward--he eliminated all other options for himself until the only one left was to demonstrate the depth of his rage and despair--and power--by killing as many people as possible. And even he couldn't believe he had come to that level of actual ruthlessness, it was somewhat surreal, even to him. He had to kept re-hashing the injustices being done to him in his mind, and he had to keep dehumanizing his intended victims, in order to keep his rage-fueled motivation to actually kill going. The heady power of being able to kill became more appealing, and stronger, than any moral prohibitions about doing it. Suicide now wouldn't be a sign of his defeat as a man--it was simply the price he'd have to pay for his killing spree, because he didn't want to go to prison.
Can you imagine boiling down your final choices in life to, either I win the lottery, when it's over $100 million, or I'll be forced to commit mass murder and suicide--because there are no other options to make life tolerable?
He really was a spoiled brat. He couldn't deal with frustration. His killing spree was his final temper tantrum over not getting what he wanted.