Republicans are significantly more likely than Democrats or independents to rate their mental health as excellent, according to data from the last four November Gallup Health and Healthcare polls. Fifty-eight percent of Republicans report having excellent mental health, compared to 43% of independents and 38% of Democrats. This relationship between party identification and reports of excellent mental health persists even within categories of income, age, gender, church attendance, and education.
One could be quick to assume that these differences are based on the underlying demographic and socioeconomic patterns related to party identification in America today...
But an analysis of the relationship between party identification and self-reported excellent mental health within various categories of age, gender, church attendance, income, education, and other variables shows that the basic pattern persists regardless of these characteristics. In other words, party identification appears to have an independent effect on mental health even when each of these is controlled for.
...income, education, gender, church attendance, and being a Republican are significantly related to self-reported mental health -- each such relationship occurring even when the impact of the other variables is taken into account.
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 (or whether some third variable is responsible for causing both to be parallel).
...the key finding of the analyses presented here is that being a Republican appears to have an independent relationship on positive mental health above and beyond what can be explained by these types of demographic and lifestyle variables.
for graphs and more details.