The General Psychopathology Factor from Early to Middle Childhood: Longitudinal Genetic and Risk Analyses

Abstract

Background: Accumulating research suggests the structure of psychopathology is best represented by continuous higher-order dimensions, including a general dimension, p-factor, and more specific dimensions, such as externalizing and internalizing factors. Here, we aimed to 1) replicate the p-factor in early childhood; 2) externally validate the dimensions with measures relating to mental health; 3) examine stability and change of the genetic and environmental influences on the dimensions of psychopathology from early- to mid-childhood; and 4) test the links between the factors and pregnancy, obstetric, and neonatal measures. Methods: The Longitudinal Israeli Study of Twins from age 3 to 9 was used for the analyses. Data was available for 2770 children at age 3, 1908 at age 5, 1020 at age 6.5, and 973 at age 8-9. Mothers reported on developmental problems, pregnancy, obstetric, and neonatal conditions, and filled in questionnaires on each twin's externalizing and internalizing symptoms. Possible correlates of psychopathology, as reported by the twins or assessed in the lab, were also included. Results: A bi-factor model that included the p-factor and specific/residualized externalizing and internalizing factors fit the data best at each wave. Longitudinal twin analyses indicated that shared environmental influences do not contribute to psychopathology and that the p-factor is highly heritable (64-73%) with a substantial proportion of the genetic influences already present at age 3. When the p-factor is accounted for, the internalizing factor was also highly heritable, while the externalizing factor was mostly explained by non-shared environmental influences. Higher p-factor scores were associated with more developmental problems and lower self-esteem. Pregnancy, obstetric, and neonatal measures were not strongly associated with psychopathology. Conclusion: Our study suggests that a general psychopathology factor is discernible in early childhood and highly heritable, with genetic factors contributing to continuity and change during childhood.

Research Review: A guide to computing and implementing polygenic scores in developmental research

“…Twin and family studies have highlighted how a single genetic dimension partly underlies diverse disorders (Lichtenstein et al, 2009;Pettersson, Anckars äter, Gillberg, & Lichtenstein, 2013;Pettersson, Larsson, & Lichtenstein, 2016). Similar investigations across childhood have pointed to substantial genetic contributions to the general psychopathology factor (P), as well as substantial genetic stability of P across time (Allegrini et al, 2020;Avinun, Knafo-Noam, & Israel, 2021). Such investigations rely on modelling common and specific psychopathology dimensions with hierarchical models, such as second-order and bifactor models (Figure 2G-H).…”

A Developmentally Informed Systematic Review and Meta-Analysis of the Strength of General Psychopathology in Childhood and Adolescence

“…The higher-order factor that accounts for the strong covariation of specific psychopathologies (e.g., externalizing psychopathology, internalizing psychopathology) is referred to as general psychopathology or p factor when including a thought disorder dimension (e.g., obsessions and compulsions, and mania; Caspi et al, 2014). Some have suggested that including a general psychopathology or p factor is necessary to fully conceptualize the structure of psychopathology (Avinun et al, 2021;Lahey et al, 2012). A general psychopathology model suggests that a single factor influences all symptoms across a range of known categorical and dimensional diagnoses, while specific psychopathology accounts for what is unique to a given set of symptoms above and beyond the general factor (Caspi et al, 2014;Lahey et al, 2012).…”

A Developmentally Informed Systematic Review and Meta-Analysis of the Strength of General Psychopathology in Childhood and Adolescence

“…The higher-order factor that accounts for the strong covariation of specific psychopathologies (e.g., internalizing, externalizing, and thought-disorder psychopathology) is referred to as general psychopathology or p factor (Caspi et al, 2014). Some have suggested that including a general psychopathology or p factor is necessary to fully conceptualize the structure of psychopathology (Avinun et al, 2021;Lahey et al, 2012). A general psychopathology model posits that a single factor influences all symptoms across a range of known categorical and dimensional diagnoses, while specific psychopathology accounts for what is unique to a given set of symptoms above and beyond the general factor (Caspi et al, 2014;Lahey et al, 2012).…”