National Institute of Mental Health - Mental Health Numbers prevalence prevalence NIMH Stats Page depression prevalent National Institute of Mental Health 13% of children prevalence National Institute of Mental Health (NIMH) National Institute of Mental Health (NIMH) weighted mena prevelance National Institute of Mental Health - Prevalence 40 million prevalence 13% of children depression depression National Institute of Mental Health depression 20% (1 in 5) Americans have a mental illness National Institute of Mental Health four percent depression National Institute of Mental Health depression National Institute of Mental Health prevalent National Institutes of Health,