To pick up Udayana's point, as already covered, the numbers are for prescriptions per 1000 people. It tells you nothing about the actual rate. One health authority, or medical practice, may prescribe all medications separately I.e. if there are three different medicines, they would issue 3 prescription, whereas a different authority may just issue 1 prescription for all 3 medicines.
Also one authority may issue prescriptions that are enough for three months treatment, whereas may only issue enough for 1 months treatment.
Nothing in the figures gives you any information on the rate of prevalence of schizophrenia in people in England. Nor are they any real use in telling you clearly if the rate of schizophrenia are higher or lower in the different areas.