The number of people living on their own has doubled, over the last three decades, to one in three in the UK and US. New research published in BioMed Central\'s open access journal BMC Public Health shows that the risk of depression, measured by people taking antidepressants, is almost 80% higher for those living alone compared to people living in any kind of social or family group. For women a third of this risk was attributable to sociodemographic factors, such as lack of education and low income. For men the biggest contributing factors included poor job climate, lack of support at the work place or in their private lives, and heavy drinking. It is known that living alone can increase the risk of mental health problems for the elderly, and for single parents, but little is known about the effects of isolation on working-age people. Researchers in Finland followed 3500 working-aged men and women for seven years and compared their living arrangements with psychosocial, sociodemographic, and health risk factors, including smoking, heavy drinking and low physical activity, to antidepressant use. Information on antidepressant medication was taken from the National Prescription Register. Dr Laura Pulkki-Råback, who conducted the research at the Finnish Institute of Occupational Health, explained, \"Our study shows that people living alone have an increased risk of developing depression. Overall there was no difference in the increased risk of depression by living alone for either men or women. Poor housing conditions (especially for women) and a lack of social support (particularly for men) were the main contributory factors to this increased risk.\" She continued, \"This kind of study usually underestimates risk because the people who are at the most risk tend to be the people who are least likely to complete the follow up. We also were not able to judge how common untreated depression was.\" While this study clearly identifies some of the factors which increase the risk of depression for people who live alone, over half the increase in risk is still unexplained. The researchers suggest that this may be due to feelings of alienation from society, lack of trust, or difficulties arising from critical life events. All these factors need to be addressed in order to begin understanding and reducing the incidence of depression amongst working age people.