40% of Europeans Are Mentally Ill Depression, dementia, alcoholism, and strokes lead the way By Mark Russell, Newser Staff Posted Sep 5, 2011 6:03 AM CDT 64 comments Comments A new study of 30 European countries has found nearly 40% of people there suffer from some sort of mental or neurological illness. (Shutterstock) (Newser) – Nearly 165 million Europeans—about 38%—suffer from depression, anxiety, insomnia, dementia, or other mental and neurological illnesses, according to a new study. And with less than a third of those getting the treatment they need, Reuters reports that these illnesses are costing Europe hundreds of billions of euros each year. "Mental disorders have become Europe's largest health challenge of the 21st century," said one author of the three-year, 30-country study. The study, which examined 100 mental illnesses and disorders, found the four most serious problems are depression, dementias, alcohol dependence, and stroke. "If you can get in early you may be able to change the trajectory of the illness so that it isn't inevitable that people go into disability," said a doctor not involved in the study. "If we really want not to be left with this huge reservoir of mental and brain illness for the next few centuries, then we ought to be investing more now."