The autism spectrum goes from neurotypical to nerdy to Asperger’s to autistic disorder. Some psychologists say that schizophrenia has a similar spectrum from neurotypical to gregarious to schizotypical to schizophrenia. These spectra fit together to form a full spectrum.
There’s a popular theory in philosophy of mind that autism is caused by a deficiency in the “theory of mind module”: the part of your brain that allows you to figure out what other people are thinking and see things from their point of view. It’s suggested that schizophrenia could be an overactive theory of mind: hallucinations are leaks from simulation of other minds, paranoid delusions arise from assuming that other people are thinking about you, etc.
It strikes me as rather stereotypical, but autism has also been framed as an overly “masculine” brain: a focus on things and logical thinking over people and play. Schizophrenia could be correspondingly “feminine”: high empathy and poor logic skills.
There’s some correlation between autism and high physical growth, and between schizophrenia and low physical growth (all covered in this paper so thorough, it must have been written by an autistic). So guess what the proposed cause of this spectrum of disorders is? Genome imprinting: your mom’s genes are trying to make you schizophrenic and your dad’s genes are trying to make you autistic; if they’re balanced, you end up neurotypical.