Have you ever had to fight the urge to trip a stranger for no reason? How about to scream in a quiet lecture? Or even to jump in front of an oncoming train?
While scary to dwell on, such thoughts are actually quite common. Research shows that up to 90 percent of people without a diagnosed mental illness experience what psychologists have labeled "intrusive thoughts."
Colloquially, the phenomenon is known as the Imp of the Perverse, a name derived from a short Edgar Allan Poe story of the same title published in 1845. The story follows a narrator who describes his irresistible urge to confess that he has murdered someone, though he is at no risk of being discovered. Poe likened these perverse thoughts to "a shadow [that] seems to flit across the brain."
The evolutionary purpose for such thoughts is unknown, but one theory by Paul Salkovskis, a psychology professor at the University of Bath, suggests intrusive thoughts are part of the brain's way of problem solving. By generating unfiltered thoughts, our subconscious ensures that we consider a wide range of solutions for potential problems in the future.
Not all intrusions are negative, but some people seem to be more susceptible to unpleasant ones, according to Shiu Wong, a research fellow at Concordia University who studies behavior and anxiety disorders. The thoughts themselves are fairly harmless, he says, but how we respond to them can be a problem. When intrusive thoughts become too frequent or compel us to action, it can be a sign of anxiety disorders such as obsessive-compulsive disorder, in which people try to control intrusions with ritualistic behaviors. Even in the non-clinical population, research shows, trying to suppress a thought only makes it more likely to occur.
So what should you do the next time the imp in your mind causes intrusive thoughts? Wong advises that we try to take comfort in the fact that everyone experiences them: "Normalizing the experience helps manage distress."