Horrible people doing what they do best: being horrible to each other. A good performance by Kieran Culkin (yes, his little brother), whose younger self is played by him. Igby is named after "Digby", Culkin's teddy bear, whom he blamed for everything when he was a kid. He lied so much that his mum started calling him "Igby" so that he couldn't use that excuse any more.
The acting's good, I guess, because none of the characters are likeable. But there's no real attempt to explain why these people are so horrible, what drives them to pop so many pills, why they're so depressed, why Igby is so dysfunctional and drops out of so many eastern seaboard schools.
Nugget: Kieran saves the family name.