Meng Hu

There is a vast amount of research on the relationships between psychological variation and political opinion. One finding that has received attention in recent years is the relationship between mental health and left-wing opinions. A number of studies have found that positive aspects of mental health (e.g., life satisfaction) and negative (e.g., depression, anxiety) relate to left-wing ideology, such that left-wing ideology relates to worse mental health and lower positivity. We sought to test to which extent these relationships hold across a wide variety of measures of mental health and political ideology. We studied a sample of fairly representative American adults on Prolific (n = 978) who filled out 76 mental health-related questions, and 41 political ideology related questions. Overall, we found that every aspect of mental health correlated negatively with overall leftism (r’s 18 diagnoses = -0.20, last 2 weeks symptoms = -0.14, MMPI-subset = -0.17, life satisfaction = -0.15, all p’s < .001). Regression models showed that diagnoses were the primary predictor of leftism, as the other measures of psychopathology did not predict leftism once diagnoses were included in the same model. Controlling for age, sex, and race reduced the strength of association by about 25%. Alternatively, one might consider that leftism causes psychopathology. Controlling for self-reported measures and demographics, the diagnosis score predicted leftism (beta = 0.10, p < .001). Measurement invariance testing found only very small amounts of bias and in different directions across items. Thus, the relationship cannot be explained as resulting from biased measurement. Finally, we replicated associations between unnatural hair color, number of piercings, and tattoos, leftism, and mental health diagnoses (r’s about 0.20).