It has been claimed that left-wingers or liberals (US sense) tend to more often suffer from mental illness than right-wingers or conservatives. This potential link was investigated using the General Social Survey cumulative cross-sectional dataset (1972-2018). A search of the available variables resulted in 5 items measuring one’s own mental illness (e.g., ”Do you have any emotional or mental disability?”). All of these items were weakly associated with left-wing political ideology as measured by self-report, with especially high rates seen for the “extremely liberal” group. These results mostly held up in regressions that adjusted for age, sex, and race. For the variable with the most data (n = 11,338), the difference in the mental illness measure between “extremely liberal” and “extremely conservative” was 0.39 d. Temporal analysis showed that the relationship between mental illness, happiness, and political ideology has existed in the GSS data since the 1970s and still existed in the 2010s. Within-study meta-analysis of all the results found that extreme liberals had a 150% increased rate of mental illness compared to moderates. The finding of increased mental illness among left-wingers is congruent with numerous findings based on related constructs, such as positive relationships between conservatism, religiousness and health in general.
Put another way, a consistently higher number of people who self-identify as liberal or left wing also self-report having suffered mental illness.
One is tempted to generalize from this finding — to say, for example, that all liberals are crazy. But that, of course, would be illogical. The correct logical interpretation is much more modest: Liberal identification is predictive of mental illness. But even that — if true — isn’t very helpful since no individual is obligated to fulfill any given general prediction. One can be liberal and sane.
More significant is the causative possibility that left-wing ideologies tend to attract and aggregate a greater number of nuts than moderate or conservative ideologies do. That (again) wouldn’t mean that being a liberal makes you a nut case, but it would mean that being a liberal puts you in social/political alignment with more nuts than would otherwise be the case. Potential consequences (evolutionary, historical and personal) abound.