This thesis is submitted in partial fulfillment ofthe requirement ofthe degree for Doctor ofClinical Psychology at the University ofBirmingham. The thesis consists ofa literature review and empirical paper. The literature review focuses on evidence for a degree ofoverlap between autistic spectrum disorder and psychosis. Evidence suggests that ASD may be a risk factor for psychosis. There may also be a sub group ofindividuals presenting with psychosis who have ASD. It can be speculated that this sub group have an early onset ofschiZ