Health & Medicine

Alzheimer's disease is the most common type of dementia, an umbrella term that refers to a collection of symptoms, including memory loss, cognitive impairment, behavior changes, and more. Broadly caused by the death of brain cells, the disease generally (but not always) emerges in older age, strikes women more often (two-thirds of cases), and currently has no cure.

Fruit flies genetically engineered to be awake for as long as they live tend to live half as long as their well-rested brethren. Analysis shows these modified flies suffer from a buildup of DNA-destroying reactive oxygen species in their guts. When enabled to sleep or provided with antioxidants that neutralize the electron-thieving molecules, the sleepless flies live as long as their counterparts, suggesting sleep loss accumulates in the gut.

Many antidepressants approach the mental health condition from the chemical imbalance theory, which proposes that symptoms are caused by an insufficient amount of monoamines or neurotransmitters. Correcting this "imbalance" meant increasing the availability of those monoamines, typically serotonin, which influences mood and sleep. This led to the development of selective serotonin reuptake inhibitors or SSRIs. This five-minute video explains how the science of antidepressants still isn't fully understood.

An Australian woman was given a brain implant in a clinical trial to help people with epilepsy. After years of struggling with life-disrupting seizures, she felt like "I could do anything"—at least until her implant was removed against her will two years later when the company that made it folded. Ethicists question whether this removal violates "neuro rights," a subset of human rights focused on the mind.

Americans live shorter lives than peers in similar nations, and the difference in life expectancy may come down to stress. This interactive illustrates how stress affects illness, disability, and overall health. Stress is a measurable physiological reaction the body activates in response to external threats. This triggering of the sympathetic nervous system, colloquially known as the flight-or-fight response, leads to increased blood pressure and cortisol levels, heightened heart rate, and the like.

Humans didn’t need modern technology to figure out that kids tend to look like their parents. But what did humans believe about genetics before we knew about DNA or cells in general? Explore this interactive timeline to see how philosophers and scientists throughout the ages tried to explain how traits are passed from generation to generation.