LPAR1 and major depressive disorder: Recently, our group was the first to identify a possible relationship between the LPA1 receptor [one of the six characterised G protein-coupled receptors (LPA1-6) through which lysophosphatidic acid (LPA) acts as an intracellular signalling molecule] and a mixed anxiety-depression phenotype, disclosing a possible neurobiological basis of this subtype of depression.