A website called Big League Politics reports findings from a Pew survey that are not terribly surprising.
Survey data from a March Pew poll indicates that white liberals disproportionately suffer from mental illness. Nearly half of self-identifying white liberals between the ages of 18 and 29 reported telling a doctor or a healthcare provider that they have a mental health condition. Only 20.9% of white conservatives in the same category reported as such.
The finding was not true for non-white respondents. There was little variation among political categories in self-report of mental issues for non-whites. Do you suppose non-whites are unlikely to get treated for mental issues, or less likely to raise such issues with a medical person? I'd guess the latter.