SHH and schizophrenia: As discussed previously, oligodendrocyte and white matter abnormalities have been widely reported in schizophrenia and affective disorders (Bernstein et al., 2014; Mahon et al., 2010; Takahashi et al., 2011; Tham et al., 2011), and the importance of Shh signalling in oligodendrocyte development is well documented.