We had a friend in college who thought you had to answer those completely honestly (and suffered from depression and anxiety). My wife worked in the back office at the time and saw her application have big ol' red marks on it, saying she was not to be hired. So, yeah. Definitely lie your face off and say you're the HAPPIEST BEST-ADJUSTED YOU
The job market is not friendly to people with depression, anxiety, and chronic illness. Do what you need to do when faced with these bullshit questions about your emotional state.