In short: Not only are Boomers more likely than their predecessors to be unhappy, suffer from more days of poor mental health, experience more mental distress, and be depressed, but they are also likely to die of causes related to mental health, including suicide and drug overdoses. Something about being born between 1946 and 1964 was not good for mental health, and being born between 1955 and 1964 was especially bad.
