Signs

For anyone who is deeply concerned with someone who is depressed, you should know that there's no small feat for someone who's struggling with D. So, when your friend, family or loved one still tries VERY hard to do any of these things no matter how difficult it is for them - acknowledge it, affirm it, and make him/her feel good for doing it.

Those who are struggling with D will most likely experience one or two of the many possible symptoms:

• Difficulty in sleeping
• Difficulty in waking up
• Losing the energy to do small things - eating, standing up, bathing, changing clothes, doing proper hygiene
• Losing focus - studying or working
• Not wanting to go to school or work
• Avoiding people
• Avoiding crowds
• Smoking when he/she is not really a smoker
• And many more - check this website 
• http://www.webmd.com/depression/guide/detecting-depression

Those above are based only on my experience so please do more research if you are serious about helping your loved one cope with depression.