People lie for many reasons. To spot a compulsive liar, look for changes in stories over time, a pattern of lying about both small and big things, defensiveness when caught and other manipulative traits that may indicate a person is inclined to avoid the truth.
Lying as a Way of Life
Those who lie compulsively often have histories that led them to it. In less stable homes where mistakes are met with violence or harsh criticism, children learn to lie as a way to protect themselves. In adulthood, these behaviors persist until the lying itself becomes a way of life even without the threat of punishment. Therefore, it is easy to spot a compulsive liar if you notice him lying about little things such as what he had for lunch, what time he got to work or who he saw that day. In many cases, these little slip-ups are easier to catch because they are less closely guarded than untruths about larger issues.
Compare the Big (and Little) Things
Compare the details of stories that they retell. In compulsive liars, it is not uncommon for details to change over time, including elements as important as people’s names or their actions in the story. It is also useful to speak to mutual friends and compare details of these stories. Many times, stories are told differently to different people.
When busted in a lie, compulsive liars are often excessively defensive or aggressive. While some agitation is expected in anyone caught not telling the whole truth, those less prone to lying tend to feel guilty, admit their errors more readily and even provide an explanation. For compulsive liars, the lies are woven so intricately with other lies that they often refuse to acknowledge the lie at all. To admit that they lied about one thing often causes a host of other lies to unravel.
Narcissists tend to exaggerate their achievements, which may lead to a pattern of lying behaviors. WebMD notes that compulsive lying and exploitation are also symptoms of antisocial personality disorder. Due to these similarities, you might be able to spot a compulsive liar through their other traits. Trouble sympathizing with others is a red flag, as is anger at being confronted, common both in narcissism and antisocial individuals. Those who seem self-involved and lack empathy may also be prone to untruths.