In both animal studies and human studies, sustained attention has been identified as a critical ability potentially impacted by prenatal methamphetamine (MA) exposure. Sustained attention is commonly referred to as the "ability to remain alert and focused over time" (Jacobson & Jacobson, p.282, 2002). In fact, sustained attention and inhibition of impulse are central in theory to effective learning and later functioning in the world (NICHID, 2003). In the developing animal brain, research suggests that the brainstem and striatum are specifically targeted by prenatal MA exposure. These areas in the adult human brain are rich in dopaminergic and serotonergic projection involved in later sustained attention. Various post-natal environmental factors have been associated with deficits in the development of sustained attention as well. Specifically, parental depression, changes in caregiver and neighborhood violence have been associated with deficits in the development of sustained attention. With preliminary evidence suggesting a relationship between prenatal drug exposure, environmental factors, and sustained attention, exploring the interplay of prenatal drug exposure, environmental factors, and sustained attention is warranted.
The sample was comprised of 48 MA exposed and 51 control 2-year-olds matched on birth weight, race, and insurance. Prenatal exposure to MA was determined by maternal report and/or positive meconium screening. Child participants were administered a mastery motivation task coded for sustained attention. Caretakers were administered the Substance Use Inventory (SUI) and Lifestyle Interview (LI) at the child's birth, the SUI and LI again during the 1 year assessment, and the Beck Depression Inventory, Conflict Tactics Scale, SUI, and LI during the 2 year assessment. MA exposed toddlers were hypothesized to display impairments in sustained attention. Additionally, postnatal environment factors and poly-substance exposure were predicted to influence sustained attention. MA was predicted to exert unique effects (controlling for other risk factors), which was analyzed in a hierarchical regression equation. Additionally, postnatal environment factors and poly-substance exposure were predicted to influence sustained attention. MA was predicted to exert unique effects (controlling for other risk factors), which was analyzed in a hierarchical regression equation. MA did not statistically significantly predict unique variance in sustained attention. A full regression model including all risk factors was hypothesized to be the best predictor of sustained attention, yet the full model did predict a statistically significant amount of variance in the sustained attention. There were no interaction effects between MA and other risk factors on the outcome variables. However, mother's of MA exposed children self reported more tobacco, marijuana, and alcohol than did mother's of control children. Additionally, MA exposed children had more environmental risk factors associated with atypical attentional development than control children.