Children, adolescents, and young adults living with life-threatening serious pediatric illness (SPI) face considerable physical and emotional tolls via their disease conditions, treatment demands, and sequelae. To guide clinical interventions and future research for young people with SPI, Barker and colleagues1 conducted a meta-analysis to estimate the prevalence of anxiety and depression in children and young people with a variety of SPI, including cancer, cystic fibrosis, HIV, thalassemia, neurological conditions, and chronic kidney disease. The authors1 found that the prevalence of anxiety and depression is higher among youth with SPI compared with the general youth population. Specifically, the pooled prevalence was 19.1% (range, 3.6%-58.3%) for anxiety and 14.3% (range, 0.0%-50.0%) for depression, which are higher than rates cited from the general population of young people in the United States (anxiety prevalence, 3%; depression prevalence, 2.1%) and United Kingdom (anxiety prevalence, 7.2%; depression prevalence, 8.1%). Of note, none of the studies included in the review reported incidence, thus limiting understanding of the timing of onset of anxiety and depression relative to the timing of diagnosis of the SPI.