(HealthDay News) -- About 15 of every 100 adults suffer from depression, according to AARP.

Depression is more than just a case of the blues. AARP offers this list of common warning signs:

  • Difficulty concentrating, problems with memory, and difficulty making decisions.
  • Becoming irritable, angry, worried, agitated, anxious, pessimistic, or indifferent.
  • Over an extended period, being sad or unexplained bouts of crying.
  • Changes in sleep habits, as well as appetite.
  • Loss of interest in activities you once enjoyed.
  • Feelings of hopelessness.
  • Unexplained aches and pains.