Spurious empirical support for the p-factor arises with the inclusion of undiagnosed cases

Background: The p-factor is thought to cause a positive manifold in psychopathology data, and many researchers presume that it is a substantive mechanism as opposed to a methodological artifact. Limited research suggests that including completely undiagnosed cases (i.e., cases without a single diagnosis) affects the dimensionality of psychological constructs, so we examined whether empirical support for the p-factor arises with their inclusion in structural models of psychopathology.Methods: We drew on data from three large, nationally representative samples of US community members, the: National Epidemiologic Study on Alcohol and Related Conditions Wave 1 (N=43,093), National Comorbidity Survey (N=5,877), and National Comorbidity Survey- Replication (N=5,692). We systematically culled undiagnosed cases from the data in increments of 10% and re-estimated structural models of psychopathology.Results: The correlation between latent externalizing and internalizing factors varied considerably as a function of the proportion of undiagnosed cases, with the correlation dropping to zero or even slightly negative when all undiagnosed cases were excluded. Also, as undiagnosed cases were removed, general factors of psychopathology explained less variance in psychopathology and weakened in terms of the extent to which it was well-represented by its indicators.Conclusions: Including undiagnosed cases in structural models of psychopathology induces a homogeneous, unidimensional structure. Ultimately, our findings raise questions about the nature of the p-factor, including whether it reflects a methodological artifact or arises due to the inclusion of cases with absence of diagnosed psychopathology.

Headaches and sleep problems in US adolescents: Findings from the National Comorbidity Survey – Adolescent Supplement (NCS-A)

Background There is limited research on the association of sleep problems with International Classification of Headache Disorders (ICHD-II)-defined headache subtypes in youth, particularly from community-based samples. This cross-sectional study examines the associations of sleep patterns, symptoms and disorders with specific headache subtypes among adolescents from the general population of the United States. Methods The sample includes 10,123 adolescents in the National Comorbidity Survey – Adolescent Supplement, a face-to-face survey of adolescents aged 13–18 years in the continental USA. Headache subtype diagnoses were based on modified ICHD-III criteria, and mood and anxiety disorders were based on Diagnostic and Statistical Manual of Mental Disorders criteria. The associations of self-reported sleep patterns and insomnia symptoms and headache status were estimated with multivariate regression models that adjust for demographic characteristics and comorbid anxiety and mood disorders. Results There was no significant difference in bedtime between youth with and without headache. However, adolescents with migraine headache reported significantly shorter sleep duration ( p = .022) and earlier wakeup time ( p = .002) than those without headache. Youth with any headache, particularly migraine, had significantly more sleep disturbances than those without headache. With respect to headache subtypes, youth with migraine with aura were more likely to report difficulty maintaining sleep, early morning awakening, daytime fatigue, and persistent insomnia symptoms than those with migraine without aura. However, these associations were largely accounted for by comorbid anxiety and mood disorders. There was a monotonic increase in the number of insomnia symptoms with increasingly restrictive definitions of migraine. Conclusion Pervasive sleep disturbances in adolescents with headache have important implications for the evaluation, treatment and etiology of pediatric headache.

Abortion Prevalence by Age at First Coitus, Race, Ethnicity, Age, and Education: Evidence from the National Comorbidity Survey Replication

Our specific aim was to report prevalence of abortion by first age of sexual intercourse, by race and ethnic groups, and educational attainment.