What actually determines whether a person has a true disorder or mental illness versus just going through a hard time. Should a time factor be taken into consideration, or is severity (such as suicidal tendencies) what should be considered? I know that CDC says that the prevalence of people experiencing depression in a two week period was 5.4%. This leads me to believe that the two-week time period may be used in classifying depression. (Be sure to cite your sources.)