“For the babies who had very low vitamin D, their risk was about twice as high as those babies who had optimal vitamin D,” says McGrath.

“But the amazing thing was that the study that was based in Denmark, where low vitamin D is quite common, we found that if vitamin D is linked to schizophrenia our statistics suggest that it could explain about 40% of all schizophrenias.

“That’s a much bigger effect than we’re used to seeing in schizophrenia research.”