By Richard Horgan Los Angeles (Knewz) — A number of Americans are clinically depressed and don’t even know it, according to a new study. According to a new report, the prevalence of depression symptoms in the U.S. population is 23 percent but increases to 40 percent when individuals with unrecognized symptoms are also included. That’s a staggering statistic. Happify Health identified the additional 17 percent via questionnaire. Even though these patients reported “no” symptoms of depression, their questionnaire scores showed they are, in fact, depressed. While additional health care costs for …