For some people, a dramatic life event like a death in the family or divorce can set off symptoms that are immediate and drastic. For others, depression manifests in slow, subtle ways that are harder for friends to notice — and sometimes even harder to diagnose. Doctors have a set list of specific symptoms, and someone meets the clinical requirements of a major depressive episode if they experience five of those symptoms during a period of two weeks. As you read through these warning signs, if they sound familiar, or if you know someone who has shown signs of a depressed mood or loss of interest, the first move is to see a doctor or qualified therapist for an official diagnosis. Most importantly, if you're personally having thoughts about harming yourself or others, please seek immediate help from a friend, medical professional or the National Suicide Prevention Lifeline at 1-800-273-TALK (8255).