Well, I thought I would do a little research.
There's is no classification in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5)—the standard for mental health diagnosis. However, research in political psychology and sociology has indicated a statistical correlation between political ideology and self-reported mental health outcomes, often noting that liberals report higher levels of anxiety and depression.
Columbia researchers look at the politics of despair.
magazine.columbia.edu
So research would suggest that if you want a happy life, stop being a Liberal.