Depression is not something that people usually diagnose for themselves. More often than not, an intervention is required. People need to step in, tell someone that they need help, move them along. However, this is not something that should be looked into on a whim. Depression should be an ongoing condition, not just a day or two of being sad. Look for the symptoms.

Are they sleeping a lot? Do they not enjoy activities that they used to like and do often? If they seem like they are just going through the motions, then it might be a problem. Look for changes to diet, habits or interests. If they used to go out a lot and suddenly stop, that might be a sign that depression is setting in.

The best way to deal with this is to sit your significant other down and talk with them. Tell them exactly what you think is wrong, and how you want them to get help. Do not try to present an ultimatum, but do make sure that you emphasize that you will be supportive. Have them take the Beck Depression Inventory and talk to a therapist, physician or someone else you both trust.

It is important to not be judgemental. People will only share their feelings with you if they feel they can trust you.

Part of developing feelings of trust is based on the belief that one will not be judged by the listener.

While there are many ways to see if someone is depressed, the simple act of talking is by far the best one.