Cross-Domain Symptom Development Typologies and Their Antecedents: Results From the UK Millennium Cohort Study

Typologies of symptom development have been used to identify individuals with different symptom development in the externalizing and internalizing domains of child psychopathology separately despite the domains' high comorbidity and shared common etiologic risk. This study identified typologies of development jointly across the 2 symptom domains in childhood and investigated their associated antecedents with a specific focus on the comparisons between overall severity of symptoms and symptom expression in one or the other domain.

Latent class analysis identified groups based on emotional and behavioral symptoms assessed at 3, 5, 7, and 11 years in the UK Millennium Cohort Study (N = 15,439). Different sociodemographic, family structure and environment, birth, infancy, and early childhood antecedents were examined.

Five groups were identified: 1. low symptoms (57%), 2. moderate behavioral (21%), 3. moderate emotional (12.5%), 4. high emotional and moderate behavioral (5.5%), and 5. high behavioral and moderate emotional (4%). Higher symptoms were predicted by larger numbers of antecedents and risk factors compared with the low symptom group and compared with moderate and high levels of symptoms in either domain (groups 5 versus 2 and 4 versus 3). Comparisons of groups with similar overall symptom levels but different dominant symptom domain (groups 2 versus 3 and 4 versus 5) indicated that apart from gender and ethnicity, there were few unique antecedents of whether children mainly internalize or externalize their symptoms.

It is possible and useful to define groupings or typologies jointly across externalizing and internalizing symptom development in childhood. Although numerous antecedents predict the experience of symptoms, there are few unique antecedents that differentiate individuals with similarly high levels of psychopathology expressed mainly as internalizing or externalizing symptoms. Identification of at-risk children and delivery of early intervention might benefit from a decreased focus on symptom domain with possible downstream effects through the life course for most common psychiatric disorders.