Prenatal exposure to drugs has been associated with changes in neurocognitive development, such as delays in language development and sensorimotor development. However, the effects of prenatal drug exposure (PDE) can also be modified by the postnatal environment. The present study explored associations between PDE and postnatal family functioning on adolescent brain development.

Parent-infant dyads were enrolled at delivery from an urban University Hospital. Eligibility included positive (cocaine/heroin) maternal/infant urine toxicology or maternal self-report of cocaine/heroin use during pregnancy. A Community Comparison (CC) sample, of the same age and key demographic, was enrolled at age 6 years. Caregiver changes were documented every six months throughout the first 7 years of the study.

Adolescents (N = 50) completed structural MRI scans. Volumetric segmentation of the hippocampus was performed using FreeSurfer v5.2. Hippocampal volume was adjusted for intracranial volume, age, and sex. At this time, caregivers and adolescents also reported on family functioning by completing the Self-Report Family Instrument. The subscales of interest were family cohesion and health competence.

Participants with PDE had more caregiver changes, reported less family cohesion, less health competence, and had larger hippocampal volumes compared to the CC group. Additionally, within the PDE group, caregiver changes were correlated with right hippocampal volume; however the bilateral hippocampal volumes of those with any history of caregiver changes vs none were not significantly different. Overall, findings demonstrate lasting impacts of PDE but suggest that postnatal caregiving environments may also contribute to neurodevelopment.