Does the association with diabetes say more about schizophrenia and its treatment?--the GLUT hypothesis.

All effective anti psychotic drugs block glucose transporter proteins (GLUTs), peripherally and in the brain. These drugs are implicated in hyperglycaemia as demonstrated in mouse and human studies. Clozapine is the strongest blocker, with Haloperidol the weakest. The GLUT hypothesis suggests that schizophrenia is partly due to poor functioning of brain glucose transporters (GLUT 1 and 3). Neuronal glucose malnutrition could result in excessive neuronal pruning (so called Crow's Type 2 with a predominance of negative symptoms) or result in recurrent/ineffective pruning (Type 1 with positive symptoms). GLUT blockade by anti psychotic agents could assist Type 1 patients to complete the pruning process by deactivating already damaged neurones and circuits, but will make Type 2 patients more cognitively impaired. Future treatment options are discussed in line with the above formulation.