Being the psychologist that I am, I simply put two and two together.
1. His mother was unwed when she gave birth to him.
Ted Bundy's mother gave birth to him as an unwed mother. The father was unknown, and therefore Ted Bundy did not have a father figure for the first year or two of his life before his mother and he moved to his grandparents'.
2. Ted had an abusive grandfather.
When Ted and his mother moved in with her parents, the grandfather would beat the dog, swing cats around, and beat the wife and scream at everyone in the house. Ted was only a toddler.
3. Cousins teased Ted about being a "bastard".
Ted was teased by cousins and was called a bastard by them, as no one knew who the father was, not even the mom. This undoubtedly caused deep-seated anger.
4. He saw his birth certificate.
When Ted was a teenager he finally read his birth certificate and became upset when he read "unknown" under "father". He began to resent his mother, and ignore her, thinking of her as a slut.
5. His serious girlfriend in college broke his heart.
Ted dated a very attractive, popular, smart, and wealthy girl in college. He really, really loved her. Then, she broke up with him and he felt the effects of this for a long while after.
6. He might have had severe bipolar disorder.
Expert psychologists have stated that he may have had this due to the study of his outrageous behavior.
7. He possibly also had multiple personality disorder.
Expert psychologists say he probably had this, and family members described him, even in his early years of childhood, transforming from a happy boy to a sullen, almost evil-looking creature at times. Prison guards stated that he would oftentimes change his appearance, like cutting his hair and switching the part in his hair. He would look like a completely different person after doing appliance altercations such as these.
8. He most likely had antisocial Personality Disorder.
Expert psychologists have stated that he probably had this, as he displayed many qualities that people who are diagnosed with this have, such as narcissism, outward charm, and charisma, lack of guilt, lack of remorse or empathy, little true personality, and the inability to distinguish right from wrong.
9. His exposure to violence in the media, pornography, and true crime detective magazines.
This is the least likely explanation, but Ted himself blamed violence on the media, pornography, and true crime detectives magazines he read as an excuse for the fueling behind his numerous murders, assaults, kidnappings, and rapes.
Glad he's dead though, eh?
The judge who gave him his death sentence said, "The crimes you are accused of have been called extremely wicked, shockingly evil, cruel, and vile" and quoted one of the jury members who said, "Ted is asking us for mercy. He gave no mercy to those girls he abducted and killed. Why should we show him any mercy?"