Anecdote showing how such questions can be highly misleading:

I know someone who has bipolar disorder. He said that online questionnaires or simple diagnostic statements like the one quoted above are often misinterpreted, that it's the severity that matters most, and many people are not able to judge that properly.

He explained that many people who answer a bipolar diagnostics question like, "Do you often feel happy and then sad a short time later?" might think to themselves, "Hmm, just yesterday I was fine and then I got kind of down..." and so would answer yes to the binary question. However, for someone with true bipolar, he gave the example that, "Last week I worked 20 hours every day and founded 2 nonprofit organizations. This week I haven't been outside at all and I tried to kill myself. Again."

This sort of analysis should be done by someone with experience; the gap between 'normal' and 'severe' may be hard to fathom.