This chapter addresses the idea that schizophrenia is a 'disconnection syndrome' from a theoretical and computational perspective. The distinction between anatomical and functional connectivity is reviewed and used as a framework to introduce empirical and computational evidence that schizophrenia involves, at some level, a disintegration of neuronal interactions. The chapter concludes with an example of computational neuroscience that relates observations on the dimensional complexity of neuronal dynamics in schizophrenia to the disconnection hypothesis.