Interestingly, WNT-dependent signalling has been previously reported to be connected to levels of BDNF, which modulates mood and is directly linked to anxiety and depression through TrkB receptor signalling.49,70,71 Furthermore, pharmacological inhibition of FAAH activity has been reported to lead to an increase in BDNF levels in rats.46-48 Our gene expression analyses in patient-derived fibroblasts show a significant upregulation in BDNF expression, although whether this is replicated in other patient tissues remains to be tested. Here, FAAH is linked to depressive disorder.