FRIDAY, Aug. 6, 2004 (HealthDayNews) -- Personality disorders are much more common in the United States than researchers had thought, affecting nearly one in seven adult Americans, a new survey finds.
Researchers say that 31 million people, or 15 percent of the adult population, suffer from at least one type of personality disorder.
Roughly half of these people had obsessive-compulsive personality disorder, and a sizable minority were paranoid and harbored an unusual distrust of others, according to the review.
"This is the first national survey ever conducted on the prevalence of seven of the 10 personality disorders," said Bridget Grant, lead author of the study, which appears in the July issue of the Journal of Clinical Psychiatry.
Researchers used definitions of these disorders from the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, which helps physicians diagnose mental health conditions.
"We interviewed face-to-face over 43,000 adult Americans that was a representative sample of the U.S.," said Grant, who is chief of the Laboratory of Epidemiology and Biometry at the National Institute on Alcohol Abuse and Alcoholism.
Grant's team asked a series of questions, and then analyzed the answers to see whether the information pointed to a personality.
"We were surprised by the 15 percent figure," Grant said. "That translates to 30.8 million Americans who have at least one of the seven personality disorders [they asked about in the survey]. I was thinking it was maybe more like 9 or 10 percent."
Most common was obsessive-compulsive personality disorder, suffered by 16.4 million (nearly 8 percent) of adults. "The person is totally preoccupied with rules, schedules, the need to have perfectionism," Grant explained. "Miserly spending habits are tied in with the obsessive-compulsive personality. They have a compulsion to hang onto money."
More than 9 million, or 4.4 percent, had a paranoid personality disorder. The person with this problem generally demonstrates patterns of distrust and is suspicious of others, she said.
Nearly 8 million (3.6 percent) had antisocial personality disorder. These people "constantly break the law, hurt other people," Grant said. They demonstrate antisocial behavior, such as hurting animals, before the age of 15.
And 6.5 million (3.1 percent) had schizoid personality disorder, in which he or she detaches from social relationships and has a very restricted range of emotional expression.
Nearly 5 million (2.4 percent) had avoidant personality disorder. "This person is very socially inhibited," Grant said. "They feel inadequate as people and get sensitive to comments."
About 4 million (1.8 percent) had histrionic personality disorder, marked by excessive expression of emotions and the seeking of excessive attention. Another 1 million (0.5 percent) had dependent personality disorder, marked by clingy behavior and the need to be taken care of excessively.
Because some people have more than one personality disorder, the numbers total more than the 30 million, the number affected by at least one such disorder.
"The survey was very well done," said another expert, Dr. William Narrow, associate director of the Division of Research for the American Psychiatric Association. "It has a very large sample size, and the methods and techniques that were used to gather the data, I think, were all very rigorous and well done."
"This is the first major survey that has attempted to take the diagnostic criteria we have for personality disorder, turn these criteria into questions and take them into the community and ask them of people in the household."
In a second paper, published in the August issue of the Archives of General Psychiatry, Grant reports that alcohol and drug abuse are likely to occur along with the personality disorders, a fact that Narrow said has long been observed by clinicians.
The value of the study for consumers, Grant said, is to inspire people to talk to their doctors if they think they might suffer from one of the personality disorders, as treatment is effective.
Learn about various mental health problems at the National Institute of Mental Health.