- Borderline Personality Disorder (BPD): between 1.6% of US adult population (nimh.nih.gov/health/statistics/prevalence/borderline-personality-disorder.shtml) and 2.7% of US adult population (ncbi.nlm.nih.gov/pmc/articles/PMC3864176/)
- Antisocial Personality Disorder: 1% of US adult population (nimh.nih.gov/health/statistics/prevalence/antisocial-personality-disorder.shtml)
- Avoidant Personality Disorder: 5.2% of US adult population (nimh.nih.gov/health/statistics/prevalence/avoidant-personality-disorder.shtml)
- Any personality disorders: 9.1% of US adult population (nimh.nih.gov/health/statistics/prevalence/any-personality-disorder.shtml). See also Lenzenweger MF, Lane MC, Loranger AW, Kessler RC (2007): DSM-IV personality disorders in the National Comorbidity Survey Replication. Biological Psychiatry, 62(6), 553-564. (ncbi.nlm.nih.gov/pubmed/17217923).
Older research published by the same National Institute of Health (NIH) indicated higher prevalences. However, these numbers are now considered too high by experts, due to the way the information was collected and the way the interviews were conducted to check if the criteria of personality disorders were satisfied. These older numbers were as follows:
- BPD may afflict up to 5.9% of adults or approximately 14 million Americans (Grant BF, Chou SP, Goldstein RB, Huang B, et al. 2008 (ncbi.nlm.nih.gov/pubmed/18426259).
- Narcissistic Personality Disorder (NPD) afflicts up to 6.2% of adults (Stinson FS, Dawson DA, Goldstein RB, Chou SP, Huang B, et al. 2008 (ncbi.nlm.nih.gov/pubmed/18557663).
Some people fit both diagnoses. Studies found that between 16% and 39% of people with BPD also have NPD (bpd.about.com/od/relatedconditions/a/Narcissistic-Personality-Disorder.htm).
As mentioned above, NIH experts estimate that nearly 10 percent of the US adult population has BPD and/or NPD (approx. 23 million Americans). Statistics in other countries are likely to be similar. BPD & NPD represent a significant portion of mental health illnesses all around the world.