The well-being of young adults in this country is much worse than it was 20 years ago, according to a new study published in the journal JAMA Psychiatry. Harvard researchers collected data from the U.S. Census, as well as online and telephone surveys, to determine various domains of well-being for adults of all ages, including happiness, health, and financial stability. Young adults between the ages of 18 and 25 had the worst well-being scores of any group. They also reported the lowest levels of physical health and the worst social connectedness of any age group.