Relapse (verb, noun, “REE-laps”)
This is a word that doctors and scientists use to describe an illness that gets worse after a time when the patient seemed to be getting better. For example, a bacterial infection may respond to an antibiotic prescribed to treat it. But a patient may not finish all their antibiotics. Or the bacteria may change, developing resistance to the drug. Then, the bacteria may come roaring back, making the patient sick again.
People can also relapse after cancer treatment. A tumor may respond to a drug and get smaller. But over time, the cancer cells might adapt to resist the drugs that once would have killed it. The cancer then can again start to grow. Mental illnesses can also relapse. Someone’s depression, drug abuse, anxiety or eating disorder might respond to treatment at first. But a new life stress might make the patient relapse.
In a sentence
People with eating disorders may recover and relapse many times, which makes the illnesses hard to treat.