In New Zealand, Methadone Maintenance Therapy is recommended for pregnant women with an opioid dependency. However adverse outcomes for infants born to these women have been consistently observed, with suggestion that with age, these children may be at an increased risk of adverse outcomes, including cognitive impairment, emotional and behavioural difficulties, and poorer educational outcomes. Despite these concerns, the longer-term impact of prenatal opioid and methadone exposure on older children and adolescents remains under studied.

To address this gap, the current study aimed to characterise the extent of caregiver-reported externalising behaviour problems in children and adolescents exposed prenatally to opioids at ages 9 and 16-18 years, compared to a non-opioid exposed control group. Additionally, the study aimed to describe the neuropsychological functioning, including measures of inhibitory control, reward sensitivity and risk-taking propensity in the same cohort, and to examine the associations these outcomes had with externalising behaviour problems at age 18.

Drawing on data from a subsample of a prospective longitudinal study, the study included data at two time points; 9 and 16-18 years (18years). The sample at 9 years included 85 children in the opioid-exposed group (OE) and 99 children in the non-opioid control group (NE). The sample at 18 years included 31 adolescents in the OE group and 45 adolescents in the NE group. Externalising behaviour problems were assessed at ages 9- and 18-years using caregiver reports from the Behaviour Assessment Schedule for Children (BASC). Laboratory-based tasks were utilized to assess inhibitory control (The Stop Signal Task), reward sensitivity (Delay Discounting Task), and risk-taking propensity (Balloon Analogue Risk Task) at age 18 years.

Results showed that at both ages 9 and 18 years, children/adolescents in the OE group exhibited significantly higher levels of conduct problems (p <.001), attention problems (p <.001), hyperactivity problems (p <.001) and overall externalising problems (p <.001) compared to children/adolescents in the NE group. The age of onset and persistence of such problems was particularly concerning, with approximately one third of adolescents in the OE group from the 18-year sample exhibiting onset of externalising problems at age 9 that persisted into adolescence (p <.01). Additionally, at age 18, adolescents in the OE group exhibited diminished inhibitory control on the Stop Signal Task (p=.05), and a heightened sensitivity to rewards in the Delay Discounting Task (p=.04) compared to the NE group. However risk-taking propensity did not significantly differ between the groups on the BART. Finally, externalising behaviour problems were significantly associated with poorer inhibitory control and heightened reward sensitivity at age 18 in the OE group.

These findings indicate that children and adolescents born to mothers with an opioid dependency during pregnancy may be at an increased risk of developing externalising behaviour problems, including, conduct, hyperactivity, and attention problems during middle childhood and adolescence. They may also experience deficits in cognitive processes such as inhibitory control and reward sensitivity that may pose additional risk of later impulsive and risk-taking behaviour, drug use, driving accidents, mental health challenges, and academic and occupational difficulties. These findings raise concerns about the behavioural development of this population of high-risk adolescents. Without targeted prevention, intervention and adequate support for these adolescents and families, these challenges may persist and lead to serious negative outcomes.