Schizophrenia is a chronic and severe mental disorder with an urgent need for new and more effective treatments. A promising novel pharmacological target in this respect is the endocannabinoid system. In particular the cannabinoid compound cannabidiol (CBD) displays a highly favourable profile for development as a new antipsychotic agent. Increasing evidence indicates a significant role for neuroinflammation in the pathophysiology of schizophrenia, especially for activation of resident macrophages of the brain: microglia. Interestingly, converging preclinical evidence suggests that microglia activation is under control of the endocannabinoid system. However, how manipulation of the endocannabinoid system affects microglia activation in humans has not been established, but it is presumably related to clinical improvement of schizophrenia patients.