Comment on New Study Casts Doubt on Diagnosis of Adult-Onset A.D.H.D.

The Environmental Protection Agency plans to adopt a new method for projecting the future health risks of air pollution that experts have said is not scientifically sound.

Worms are wriggling into Earth’s northernmost forests, creating major unknowns for climate-change models.

An Ebola outbreak in eastern Congo — the second-largest in history — is escalating in part because locals don’t trust health workers and government officials.

An Ebola outbreak in eastern Congo — the second-largest in history — is escalating in part because locals don’t trust health workers and government officials.

So-called ‘heartbeat’ legislation restricting abortion as early as six weeks into pregnancy has started a conversation about when most women actually learn that they’re pregnant.

The rise of the more potent fentanyl in its place has put a generation of older users, who had managed their addiction, at far greater risk of overdose.