The Rugrats were really just a figment of Angelica's imagination. Chuckie died in 1986 along with his mother; that's why Chaz is a nervous wreck all the time. Tommy was born in 1988, but he was a stillborn. That's why Stu is constantly in the basement, making toys for the son who never had a chance to live. The DeVilles had an abortion in 1990. Angelica couldn't figure whether the child would've been a boy or a girl, thus creating the twins.
As for "All Grown Up", the teenage Angelica became addicted to various narcotics, which further aggravated her schizophrenia. This brought her back to her childhood and the creations she'd obsessed over. Because of the time that had passed between the present and the last time she interacted with her delusions, she made them older. Angelica was constantly taking hits of acid so that she would never have to live without them. To her, they were the only company in a judgemental world.
Angelica's mom actually died of a heroin overdose in 1982, just after Angelica was born. Drew, in his depression, married a gold-digging whore. He had lost his mind after the death of his wife and was in denial that she was ever a prostitute. Angelica idolized her because she fooled herself into thinking she was her real mom. But she always had a concept of her real mom, Cynthia. The barbie doll she was so attached to was fashioned in the woman's image, with an unwashed orange dress and jacked-up hair. Later in life, she followed in her mom's footsteps with drugs, dying of an overdose at age 13, when 'All Grown Up!' was "cancelled".
The only Rugrat not to be fictional was unborn Tommy's brother Dil. However, Angelica didn't know the difference between Dil and her creations, although Dil didn't follow her commands. After endless crying and a refusal to disappear like the others did when Angelica was angry with them, she hit him. Due to this, he sustained a brain hemorrhage, which resulted in a deformation. As he grew up, his damage only became more evident, and by the time he was 9 in "All Grown Up!", he lived as an outcast, ridiculed for his weirdness and retardation. The immense guilt over this is what led Angelica to her drug use and to un-create the Rugrats briefly, until her experience with hallucinogenics.
On a trip to Paris to find love, Chaz married a woman named Kira. He was actually going to marry a different woman named Coco, but she just wanted him for his money. Kira had a daughter named Kimi that was torn from her because she was a cocaine addict (Angelica imagined her from Kira's stories). Upon returning to America, Chaz and Kira got engaged, and she got her green card. It was actually a really happy and romantic story. Kira continually struggled with addiction, but was relatively happy with her life and Chaz.
Suzie was actually Angelica's only friend. She entertained the thought of Angelica's creations for the girl's sake. She later became a psychologist, and teamed up with Nickelodeon to make the Rugrats. When Angelica died of the overdose, Suzie helped arrange her funeral. Angelica spent the last days of her life in the back of the school cafeteria, imagining friends around her and playing with the lives of her creations.
Original author unknown
Originally uploaded on October 31st, 2011