Don't worry, be happy: If you're a Republican, those words should be easy to follow.
A roundup of Gallup health polls over the past four years finds that Republicans are far more likely than Democrats to report having excellent mental health.
The survey found that 58 percent of Republicans polled reported having excellent mental health. Only 38 percent of Democrats and 43 percent of Independents reported the same.
The study concluded it was unclear why there was such a strong correlation, but the relationship between party affiliation and mental health was virtually constant even within categories of income, age, gender and other factors.
"The reason the relationship exists between being a Republican and more positive mental health is unknown, and one cannot say whether something about being a Republican causes a person to be more mentally healthy or whether something about being mentally healthy causes a person to choose to become a Republican," the study said.
The study speculated that the fact that Republicans have on average higher incomes than members of others parties could play a factor. But in the study, even Republicans making less than $50,000 a year reported having excellent health far more than Democrats earning the same.
The study was based on interviews with 4,014 American adults who were at least 18 years old, conducted from November 2004 through 2007. The margin of error was 2 percent.