Many of us have felt sad or alone at some point. When sadness becomes too much to handle, or hangs on for a long time, it may be a sign of depression.

Depression is a medical condition that can affect our ability to work, study, interact with people or enjoy our lives. It can be caused by imbalances in brain chemistry. But it can also be triggered by things that happen to us or around us like stress, traumatic events, relationship problems or break-ups, physical illness, or lack of sleep.

Not everyone experiences depression in the same way. Depressed people may appear withdrawn and apathetic, or they may be aggressive and self-destructive. Some people may be depressed about a specific problem, while others feel deeply unhappy without knowing why. Sometimes, a depressed person may even appear “fine” to their friends and family. The common thread is an overwhelming, persistent feeling of loneliness and hopelessness.

Depression often first appears during the teenage and college years, so it’s really important to look out for the warning signs during those years. And if you’re worried that you or a friend might be struggling with depression, reach out and get help. Depression is treatable and there are ways to feel better.

Here are some symptoms of depression:

  • Persistently sad, anxious, irritable or empty mood
  • Loss of interest in previously enjoyable activities
  • Withdrawal from friends and family
  • Trouble sleeping or sleeping too much
  • Fatigue and decreased energy
  • Significant change in appetite and/or weight
  • Overreaction to criticisms
  • Feeling unable to meet expectations
  • Difficulty concentrating, remembering details, and making decisions
  • Feelings of worthlessness, hopelessness or guilt
  • Persistent physical symptoms such as headaches, digestive problems or chronic pain that do not respond to routine treatment
  • Substance abuse problems
  • Thoughts of suicide or suicide attempts