Endocannabinoid Control of Microglia Activation as a New Therapeutic Target in the Treatment of Schizophrenia

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. In this project, we propose to study endocannabinoid control of microglia activation as a new therapeutic target in the treatment of schizophrenia. Using a placebo-controlled, randomised, double-blind design, we will investigate this in a group of 36 recent-onset schizophrenia patients after four weeks of daily CBD treatment, in addition to their regular antipsychotic medication. First, we will examine if CBD treatment attenuates microglia activation and levels of peripheral inflammatory markers. In vivo microglia activation is assessed before and after treatment using 1H-MRS, with the level of myo-inositol being regarded as a marker of glia function. Second, we will determine if reduced microglia activation and levels of inflammatory markers relate to improvement of symptomatology and cognitive function. Third, we will assess how microglia activation and levels of inflammatory markers before treatment predict the clinical response to CBD.