Nearly 40 million U.S. adults decided not to fill a prescription medication from a doctor in 2008 because of the cost, according to a new study by Manhattan Research, a pharmaceutical and healthcare market research firm. The study found that women and patients with neurological and mental health conditions were the most likely to give up their medication due to cost. Adult ADHD, chronic pain, and depression were among the 10 condition groups most affected by drug costs. 

Studies show that doctors are often unaware of drug costs and don't ask patients whether cost is an issue. If you're struggling to keep your drug costs under control, raise your concerns with your doctor. Ask whether a less expensive generic drug would do just as well.

Lowering costs by splitting pills or getting them by mail order might also be an option. And many brand-name drugs are available free of cost to low-income people without insurance. Your doctor or the office staff can help you find out whether you are eligible for a drug-assistance program.

For more on lowering prescription drug costs, read our recent advice on shopping around and discount programs. And see our free Best Buy Drugs reports on conditions such as heart disease, diabetes, and chronic pain, and our Money Saving Guides on prescription drugs assistance programs, splitting your pills, and more.