Medical experts and analytics say that by year 2020 depression will be the second largest killer of humans after heart diseases in the world. It is a striking fact, isn’t it? However, people often underestimate the threat of depression, trying to explain it by stress, lifestyle pace or just low spirit. Happily, nowadays the public interest to the problem of depression grows, and people make use of the available information on depression to overcome this disorder. The quiz below is to help our readers evaluate their knowledge of basic facts on major depressive disorder as one of the most common types of depression.