Summary Depressionremits and recurs, but amongwhatproportion of the population? Retrospective surveys

Depression (ICD–10 F32, F33 or DSM equivalent) is a common disease. In 1990, in established market economies, depression was estimated to be second only to ischaemic heart disease as a cause of disease burden. It was the largest single cause of non-fatal burden (Murray & Lopez, 1996). It is a disease that often remits and recurs (Andrews, 2001), but does it remit and recur among a restricted number of people or will it, like influenza, affect most of us in the fullness of time? Two recent reviews, that conducted secondary analysis of data from established market economies, came to very different conclusions. Waraich et al (2004) estimated the lifetime risk of ever having a major depressive episode to be 6.7%, whereas Kruijshaar et al (2005) estimated the lifetime risk to be 40% in women and 30% in men. Can both be correct?