from ap: If you think they're out to get you, you're not alone. Experts now say that paranoia may be a lot more common than previously thought. British psychologist Daniel Freeman, for example, said nearly one in four Londoners regularly have paranoid thoughts. A British survey of more than 8,500 adults found that 21 percent of people thought there had been times when others were acting against them. Another survey of about 1,000 adults in New York found that nearly 11 percent thought other people were following or spying on them. Experts warn that paranoia can be stressful, and result in more social isolation, hostility and possibly even crime. Still, some say a little paranoia could be helpful. A professor in Texas said it's a dangerous world, so it's good to be on guard.