While everyone experiences symptoms of depression from time to time,{{science-fact}} these symptoms are usually transient and often in response to outside stressors. Although depression is sometimes triggered by life events, sufferers also often describe feeling sad for no reason at all.{{science-fact}} | While everyone experiences symptoms of depression from time to time,{{science-fact}} these symptoms are usually transient and often in response to outside stressors. Although depression is sometimes triggered by life events, sufferers also often describe feeling sad for no reason at all.{{science-fact}} |