Infant Temperament and High-Risk Environment Relate to Behavior Problems and Language in Toddlers

Objective: This study examined the role that easy infant temperament and cumulative environmental risk play in predicting cognitive, language, and behavioral outcomes in 3-year-old children at high social risk. Methods: Subjects were 412 mother-infant dyads, recruited at birth, participating in a longitudinal study examining the effects of prenatal methamphetamine on child development. This analysis includes a subsample (n = 290) of the study with a completed 3-year visit. Temperament was assessed by the Infant Behavior Questionnaire at 12 months. Factor analysis from well-validated measures generated easy and difficult temperament profiles and a profile for high-risk environment. Caretaker receptive vocabulary served as a proxy for intelligence quotient. Outcomes at 3 years included motor and mental development, behavior problems, and language. Linear regression and hierarchical linear modeling examined the effects of temperament, high-risk environment, and caregiver receptive language on outcomes adjusting for maternal drug use and demographic and socioeconomic covariates. Results: Internalizing and externalizing behaviors were lower in children with easy temperament and higher with increased environmental risk. Easy temperament attenuated behavioral problems only in the setting of lower environmental risk. Caregiver receptive language was associated with lower internalizing scores. High-risk environment and temperament factors were not related to cognitive or motor outcomes. Prenatal methamphetamine exposure was not associated with 3-year-old outcomes, nor did it alter the protective effects of an easier temperament on child behavior. Conclusions: Children growing up in adverse social environments had increased behavioral problems and compromised language development. Conversely, an easy temperament acts as a protective factor for social-emotional development and could be related to resilience.