An unusual study of people with brain damage, caused in most cases by a stroke, suggests the compulsion to light up might be driven by the same little-studied brain region, the insula, that helps us make sense of hunger pangs, nervous twitches and all sorts of visceral body signals.

Researchers said the findings identify an important new target for research into the biological underpinning of addiction. It might even be possible to tamp down cravings, or at least monitor them more precisely, with therapies that target the insula, such as biofeedback training.