ERBB4 and autism spectrum disorder: Administration of haloperidol to rats led to specific reductions of PIK3CD brain expression; and furthermore, specific blocking of PIK3CD blocked amphetamine-induced hyperlocomotion (a rodent model of psychosis-like behavior, related to a hyperdopaminergic state) in mice.66PIK3CD has also been shown to be important for the biochemical function of the NRG1–ERBB4–PI3K signaling pathway, that is, involving two leading candidate genes for schizophrenia (NRG1 and ERBB4).66 Dysregulation of PI3K activity has been implicated in both autism spectrum disorders and schizophrenia.67, 68, 69