Overdiagnosis happens when people get a diagnosis they don’t need. It can happen when people without symptoms are diagnosed and then treated for a disease that won’t actually cause them any symptoms, and it can happen for people whose symptoms or life experiences are given a diagnostic label which brings them more harm than good.

Although hard to believe, there’s growing scientific evidence suggesting many people are overdiagnosed across a lot of different conditions, including asthma, breast cancer and high blood pressure.

One common way overdiagnosis can happen is when healthy people who attend screening programs or receive tests during check-ups are diagnosed and subsequently treated for the early form of a disease which would never in fact have harmed them. With breast cancer screening for example, a systematic review of studies published in the British Medical Journal suggests that up to one in three of the cancers detected via screening may be overdiagnosed. There are similar concerns with overdiagnosis of prostate, thyroid and kidney cancers.

Another way in which overdiagnosis can happen is when the definitions of diseases are broadened so much that people with very mild problems, or people at very low risk of future illness, are classified as being sick, given a label, and then offered treatments which may do more harm than good. For example there are suggestions some children are being overdiagnosed with Attention Deficit Hyperactivity Disorder, with similar concerns being expressed in the medical literature about potential overdiagnosis of chronic kidney disease, osteoporosis and bipolar disorder.

To read more about the problem, go to our Readings page.