Associations between infant and toddler regulatory problems, childhood co-developing internalising and externalising trajectories, and adolescent depression, psychotic and borderline personality disorder symptoms.

Background: Early regulatory problems (RPs) are associated with childhood internalising and externalising symptoms. Internalising and externalising symptoms, in turn, are associated with adolescent psychopathology (e.g. personality disorders, depression). We examined whether RPs are directly associated with adolescent psychopathology, or whether associations are indirect via childhood internalising and externalising symptoms.

Methods: We used data from the Avon Longitudinal Study of Parents and Children. Mothers reported on their child's RPs at 6, 15-18 and 24-30 months, and internalising and externalising symptoms at 4, 7, 8 and 9.5 years. Adolescent psychotic, depression and BPD symptoms were assessed at 11-12 years. Children were grouped by their patterns of co-developing internalising and externalising symptoms using parallel process latent class growth analysis (PP-LCGA). Path analysis was used to examine direct and indirect associations from RPs to the three adolescent outcomes.

Results: There were four groups of children with distinct patterns of co-developing internalising and externalising (INT/EXT) symptoms. Most children (53%) demonstrated low-moderate and stable levels of INT/EXT symptoms. A small proportion (7.7%) evidenced moderate and increasing INT and high stable EXT symptoms: this pattern was strongly predictive of adolescent psychopathology (e.g. depression at 11 years: unadjusted odds ratio = 5.62; 95% confidence intervals = 3.82, 8.27). The other two groups were differentially associated with adolescent outcomes (i.e. moderate-high increasing INT/moderate decreasing EXT predicted mother-reported depression at 12, while low stable INT/moderate-high stable EXT predicted child-reported depression at 11). In path analysis, RPs at each time-point were significantly indirectly associated with symptoms of BPD and child- and mother-reported depression symptoms via the most severe class of INT/EXT symptoms.

Conclusions: Consistent with a cascade model of development, RPs are predictive of higher levels of co-developing INT/EXT symptoms, which in turn increase risk of adolescent psychopathology. Clinicians should be aware of, and treat, early RPs to prevent chronic psychopathology.