Diabetes and Central Nervous System breakthrough

A recent study shows that Diabetes seems to be linked to the nervous system. This is indeed a surprise. However, the most surprising fact is that it was not discovered earlier as it is known that mental illness is linked to diabetes. More specifically, according to several studies dating back fifty years ago we could see the following :

... based on a retrospective review of medical data for 569 randomly selected patients with the two disorders admitted to a state psychiatric hospital between 1940 and 1950—before antipsychotic medications were available-found that metabolic disturbances were significantly greater in those patients than among the general population...