Science

https://www.psychologytoday.com/us/blog/5-types-of-people-who-can-ruin-your-life/201805/are-narcissists-and-sociopaths-increasing

Personality disorders are a significant, but barely recognized, public health problem in the United States and around the world. Two personality disorders, in particular, cause a great deal of disruption in the workplace, conflict in marital relationships, and are prevalent in criminal populations. And they appear to be increasing.

In 1994, the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders was published (the DSM-IV). It stated that estimates of the prevalence of Narcissistic Personality Disorder (NPD) were “less than 1% in the general population.”1 Regarding sociopaths (the DSM uses the equivalent term Antisocial Personality Disorder or ASPD), it said that overall prevalence “in community samples is about 3% in males and 1% in females.”2

Between 2001 and 2005, the National Institutes of Health (NIH) funded the largest study ever done regarding the prevalence of personality disorders in the United States. Structured interviews were done with approximately 35,000 people who were randomly selected to be representative of the U.S. adult population in a variety of ways including age, income, gender and region. This study found that 6.2% of the general population would meet the criteria for NPD3 and 3.7% would meet the criteria for ASPD (5.5% male and 1.9% female).4

This could be seen as a huge jump for NPD and a significant increase for ASPD in about a decade. Or, this could be explained by the fact that the 1994 estimates were based on small studies with varying methodology, compared to the sheer size and standardization of the NIH study.

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