I read this some years ago and it seemed then that, at least subjectively, it was more believable as a presentation of a "high-functioning autistic"/"ASpie"'s experience than several other novels I'd read with protagonists who were identified on the spectrum (which, despite the variety of experience on the spectrum, still never gave me the impressions that their authors got anything-about-"it"); reading it again in the last week confirmed me in this. 
 Lou's opening interchange with his assigned psychologist wsa a good example of this.