We applied different diagnostic rules for diagnosing personality disorders to the NESARC epidemiological study of over 40,000 individuals. Specifically, unlike previous NESARC publications, we required that each personality disorder criterion be associated with significant distress or impairment in order to be counted toward a personality disorder (PD) diagnosis. Results demonstrated significant reductions in prevalence rates for PDs (9.1% versus 21.5% using original NESARC algorithms), and these revised prevalence rates were much more consistent with recent epidemiological studies in the U.S. and Great Britain. We also found gender differences in the prevalence rate for most PDs. Comorbidity analyses revealed strong associations between PDs and alcohol dependence, drug dependence, and tobacco dependence. PD diagnoses were also associated with scores on dysfunction and impairment, perceived stress and less social support, lifetime history of suicide attempts, interpersonal difficulties, and problems with legal authorities.