\" \" A 2018 study found that Washington, D.C. takes the cake as the most psychopath-dense section of the United States. HowStuffWorksAny self-respecting single has joked about the scores of psychopaths populating the dating scene. According to a new study titled \"Psychopathy by U.S. State,\" (just some light lunchtime reading), Washington, D.C. takes the cake for the most psychopath-dense section of the nation. AdvertisementNow that you've got those Beltway jokes out of your system, it's worth knowing that Connecticut, California and New Jersey aren't too far behind D.C. when it comes to psychopathy. Now That's Interesting Experts believe psychopaths make up about 1 percent of the general population and up to 25 percent of the prison population.