GPR55 and schizophrenia: For example, dysregulation of glutamatergic signaling within the hippocampus is a well-established biomarker for schizophrenia-related psychosis.31,32 Thus, given that both CB1R and GPR55 transmission mechanisms within the vHipp appear capable of strongly modulating extrinsic dopaminergic activity states in the mesolimbic pathway, this suggests that localized cannabinoid abnormalities in the vHipp may cause dopaminergic and related affective and cognitive disturbances through either of these receptor substrates.