In a typical country, one in five people suffers from a mental illness, the great majority from depression or crippling anxiety. Mental illness accounts for half of all illness up to age 45 in rich countries, making it the most prevalent disease among working-age people; it also accounts for...

Do other peoples' incomes reduce the happiness which people in advanced countries experience from any given income? And does this help to explain why in the U.S., Germany and some other advanced countries, happiness has been constant for many decades? The answer to both questions is "Yes". We...