Merikangas was born Kathleen Ries to F. William and Dorothy Campbell Ries.[2] Merikangas earned her bachelor's degree summa cum laude in experimental psychology and music from University of Notre Dame in 1973.[3][4] She received her master's degree from University of Pittsburgh School of Medicine, which was sponsored by National Institute on Alcohol Abuse and Alcoholism. During this time, she did her clinical training and internship at the Western Psychiatric Institute and Clinic at the University of Pittsburgh School of Medicine. She earned her Ph.D. in chronic disease epidemiology from University of Pittsburgh School of Public Health in 1981, focusing on conducting clinical research on the affective disorders.[3] With the help of Career Development Award from National Institute of Mental Health, Merikangas did her postdoctoral work in population genetics and genetic epidemiology at Yale University School of Medicine.