Cognitive and functional outcomes at age 21 after prenatal cocaine/polydrug exposure and foster/adoptive care

Abstract

Objective: Prenatal cocaine exposure (PCE) has been linked to specific cognitive deficits and behavioral outcomes through early adolescence but there is little information on adult outcomes nor on the relationship of environmental interventions, such as foster/adoptive care, to outcomes.

Methods: At 21 years, data were available on 325 young adults, [163 PCE and 162 non-exposed (NCE)], primarily African-American, with low SES, who were followed from birth in a prospective longitudinal cohort study. Participants were administered the Wechsler Abbreviated Scale of Intelligence (WASI-II) and surveyed regarding high school completion, problematic substance use, and incarceration/probation history. In the PCE group, 32 remained in non-kinship foster/adoptive care (PCE/FA) from early in life (< 4 years) to 17 years. Group differences were examined through t-tests, MANOVA/ MANCOVA with post-hoc analyses, comparing outcomes and environmental correlates of young adults with PCE vs. NCE, as well as outcomes of PCE young adults in non-kinship foster/adoptive care (PCE/ FA) vs. PCE in birth/kinship care and NCE young adults.

Results: At 21 years, young adults with PCE had lower mean Full Scale (83.7 ± 10.4 vs. 87.3 ± 12.5, p < .01) and Perceptual Reasoning IQs (87.3 ± 11.5 vs. 91.4 ± 13.9, (p < .02), lower high school completion rates (75% vs. 86%, p < .02), and were marginally more likely to have been on probation than NCE young adults, but did not differ in Verbal IQ, self-report of problematic substance use or incarceration. Young adults with PCE in F/A had similar lower IQ scores but had better verbal skills and high school graduation rates that did not differ from NCE young adults (80.6 vs 86.2%, p > .05). They had higher drug exposure at birth and more experiences of maltreatment (p's < 0.05) but their home environment quality was better and lead levels lower (p's < 0.05) than those of young adults with PCE in birth/kinship care.

Conclusions: Young adults with PCE had lower Perceptual Reasoning and Full-Scale IQ scores, independent of caregiving placement, compared to non-exposed young adults. Young adults with PCE placed in non-kinship foster/adoptive care had lower lead levels, more stimulating home environments, better vocabulary skills and were more likely to graduate from high school than those in birth/kinship care,but were not different in their self-report of problematic substance use, or experiences of incarceration or probation. Our data suggest that some cognitive deficits observed in young adults with PCE may be biologically based, but that some functional outcomes can be modified through environmental interventions. Our data also reflect the complexity of disentangling the effects of teratologic exposures on long term outcomes across a variety of domains and the need for studies of children in the foster care system.

Keywords: Cocaine; Foster care; High school graduation; IQ; Incarceration; Perceptual reasoning; Prenatal substance exposure; Substance use; Young adult.