Project Summary/Abstract Growing up in a lower-income family robustly predicts worse mental health in adolescence and early adulthood. How does economic inequality “get under the skin” of the developing child and via what mechanisms does it increase risk for mental illness? Moreover, could supplements to family income at critical developmental periods help to prevent later youth mental illness? To address these questions, we leverage an innovative existing double blind randomized controlled trial of 3-years of substantial ($1,000/month vs. $50/month) income supplements to parents. By experimentally studying the impacts of these income supplements on families and subsequent youth development, we can examine causal pathways from family income to mental illness via family stress and neuroimmune mechanisms in ways never done before. Moreover, by measuring the longer-term impact of 3 years of income supplements to parents on their child’s neuroimmune signaling and risk for mental illness, we can examine the policy implications for child development of unconditional cash transfers to parents and identify how and for whom these supplements help. We will test these basic and translational questions in a sample of 1,200 youth with lower-income parents randomly assigned to receive either a substantial monthly income supplement ($1,000/month, intervention group) or a minimal monthly supplement ($50/month, control group) for 3 years, starting when youth were between age 5 – 14 years old. We will follow up with youth and their parent 1 – 2 and 3 – 4 years after the intervention (youth will be age 10 – 18 at first follow-up) and examine whether income supplements predict better youth mental health during adolescence, as well as whether factors like child age, gender, and neighborhood quality modulate intervention effects. Additionally, we explore family stress mechanisms through which the intervention may impact child mental health. Finally, we will measure peripheral inflammation (inflammatory biomarkers and classical monocytes) and use MRI to assess threat, reward, and regulatory neural activity and connectivity among 500 of these youth. Our central hypothesis is that income supplements will decrease family and youth stress and improve parenting, which will improve neuroimmune signaling and decrease psychopathology. Moreover, these effects will remain years after termination of the transfers and be strongest among families who received the intervention earlier in the child’s life. This research will provide timely, public health knowledge that will help policy makers understand the longer-term brain, immune, and mental health impacts of cash transfers to parents, while also advancing the science of the sociocontextual and neuroimmune pathways through which poverty and structural inequality impact risk for psychopathology.

Project Narrative The proposed study will elucidate the family, immune, and brain pathways through which variation in family income impacts risk for mental illness in youth and adolescents. By using an existing randomized controlled trial of 3-years of substantial ($1,000/month vs. $50/month) income supplements to families, the study will be able to experimentally assess whether these pathways have a causal influence on developmental outcomes and evaluate the longer-term outcomes of the intervention, which will have important scientific, treatment, and policy implications by testing the neuroimmune and behavioral outcomes of unconditional cash transfer to parents.