Occasional sadness or anxiety is NOT uncommon in children and adolescents. But certain symptoms like persistent sadness, hopelessness and significant behavior changes that impact the ability to function in school, family or social situations can signal depression in young people. An estimated 2% of young children, and 4% to 8% of adolescents suffer from depression, a mental illness that can cause numerous emotional and physical symptoms. Depression can have lasting consequences that result in setbacks to a child's emotional growth, social life and ability to succeed at school. Studies also show that young people who struggle with depression often experience significant disadvantages in adulthood, underscoring the importance of early diagnosis. Yet another - and extremely critical - reason to seek professional help for childhood or adolescent depression is the connection between depression and suicide, which is the third leading cause of death among young people in the 10-to 24-year-old age group. If depression symptoms persist at least two weeks, it's important to visit your family physician to rule out physical causes of the depression symptoms. If depression is suspected, your doctor may suggest a mental health professional for a comprehensive evaluation. To diagnose depression accurately in young people, clinicians rely on the same DSM-IV diagnostic criteria published by the American Psychiatric Association used for diagnosing adults. However, the criteria acknowledge that diagnoses may be more difficult in young people because symptoms vary according to age and development. Meeting the diagnostic criteria for depression involves the presence of at least five of the nine symptoms listed in the DSM-IV, that persist for at least two weeks. Symptoms include persistent sadness, loss of interest in activities that were once enjoyed, changes in appetite, sleeping or behavior, fatigue, difficulty concentrating and thoughts of suicide. Challenges in diagnosing depression in young people often include the inability of younger children to fully describe how they feel, as well as teens that may refuse to engage in conversation. To help ensure the most comprehensive understanding of the depression symptoms, the mental health evaluation typically involves interviews with the child and parents, and may include any useful information that other family members, friends, teachers or counselors can provide. Depression in children and adolescents is a serious mental illness that can be frightening for children as well as their parents. But it can be treated successfully. If you suspect your child may be depressed, it's important to consult a mental health professional as soon as possible.