Thombs and colleagues have shown that screening consecutive attendees in primary care settings in high income countries for depression is not worthwhile. However, it is dangerous to generalize from high income countries such as the USA to the rest of the world. The positive predictive value of any screening test for depression is affected by the prevalence of the disorder in the population being considered. Populations with an increased prevalence of depression, such as those with chronic physical disorders, or with a history of depression or other mental health problems may benefit from screening, even in high income countries. Populations in low and middle income countries (LMIC) may also benefit from screening if they are experiencing severe social adversity, including poverty. Two examples are given, in which screening with a brief screening questionnaire was followed by collaborative stepped care, to the considerable benefit of the patients in LMIC. Please see related article: http://www.biomedcentral.com/1741-7015/12/13.