Doctors in West Virginia write an average of 17.7 prescriptions for every resident of the state, far above the national per-capita rate of 11.5, Forbes reported Aug. 18.

Healthcare information firm Verispan said in a new report that Southern states tended to have the highest rate of prescription-drug use -- doctors in Alabama, South Carolina, Tennessee, Arkansas, Louisiana, Kentucky and Missouri all wrote prescriptions at a higher-than-average rate.

Experts said that the explanation lies in the fact that these states have higher rates of heart disease, obesity, and diabetes -- "chronic diseases that are largely preventable and are linked to lifestyle and physical activity," according to Jane Barlow of pharmacy-benefits management firm Medco Health Solutions.

West Virginia, for example, exceeds the national average for smoking, heart-disease deaths, diabetes, obesity, and mental-health problems (antidepressants were the third most prescribed drugs in the state, the report said).