Association of Serum Interleukin 6 and C-Reactive Protein in Childhood With Depression and Psychosis in Young Adult Life

Abstract

Depression is a leading cause of disability worldwide.¹ It affects approximately 16% of Americans during their lifetime, with approximately 25% of these cases beginning before age 20 years.^2,3 Psychotic disorders (including schizophrenia) are some of the most enduring neuropsychiatric illnesses, with a lifetime risk of 1% to 2% in the United States.⁴ Globally, schizophrenia is an important cause of disability among young people and is associated with premature death, largely from heart disease.^5,6 Longitudinal studies^7-11 have linked higher levels of circulating inflammatory markers such as interleukin 6 (IL-6) and C-reactive protein (CRP), with subsequent risk of type 2 diabetes mellitus and heart disease. These chronic physical conditions often occur concomitantly with depression and psychotic disorders^12,13 and may share pathophysiologic mechanisms.