An insomnia therapy that scientists just reported could double the effectiveness of depression treatment is not widely available nor particularly well understood by psychiatrists or the public. The American Board of Sleep Medicine has certified just 400 practitioners in the United States to administer it, and they are sparse, even in big cities.That may change soon, however. Four rigorous studies of the treatment are nearing completion and due to be reported in coming months. In the past year, the American Psychological Association recognized sleep psychology as a specialty, and the Department of Veterans Affairs began a program to train about 600 sleep specialists. So-called insomnia disorder is defined as at least three months of poor sleep that causes problems at work, at home or in relationships.