How to keep the brain healthy

Disorders of the brain are a growing worry. Twelve mental-health conditions affect about 970m people around the world according to the Global Burden of Disease Project: more than one in ten of the population. Patchy data mean that this figure could well be an underestimate. On top of that, neurological problems, such as stroke, dementia, migraine, Parkinson’s, epilepsy and brain injury are collectively the leading global source of disability. Ageing populations with unhealthy ways of life are likely to make this problem much worse everywhere.