(FORTUNE Magazine) – Is somebody in your office unusually apathetic lately, or irritable, or anxious, or all three? Chances are he's suffering from clinical depression, which is on the rise and hits about one in five Americans. It's an expensive problem. Researchers at MIT and Paul Greenberg at Analysis Group Economics in Cambridge, Mass., put the cost at $44 billion a year, with $24 billion of that in absenteeism and lost productivity. That's why about 70 big companies have signed up for the nonprofit National Depression Screening Project in Wellesley, Mass. Troubled employees can call this phone service and talk with counselors who can steer them to professional help. Says Harvard Medical School psychiatrist Douglas Jacobs, the program's founder: "If you can intervene in a case of depression early, before it becomes really debilitating, then treatment is both cheaper and more effective."