When you're living your normal life with confidence and passion and enthusiasm, Depression seems like a distant memory. A silly phase that's long gone. It seems like you've been cured, and so you're more willing to tell the world about it. Conversely, when you're facing the reality of Depression, it is a deep, hidden secret. This is why it's a problem.
Only a few weeks ago, I was living in my special, self-assured little world. I was social, talkative, optimistic, and feeling ready to take on the world! Sadly, the past few days have been much more Hellish inside my brain. I've reverted back to anxiety, seclusion, self-destruction, and obsession. As usual, rather than reaching out to others and requesting their help, I've become a hermit. I only go outside when I absolutely must, I only talk to people when I must, and my sense of self-worth and love is completely depleted.
Some people ask what happened, what "triggered" this, what can I do, they do, we all do? By nature, people are kind (despite what my intensely misanthropic Depressed brain says) and they want to be there for those facing this illness. However, the brain chemicals have no ears. They don't care who listens or hugs or "is there for me". Even if I meditate or chant or spin 3 times while lighting sage on fire, these things won't help. Maybe some people, though. Spin away, if it helps.
So, what can you do, as someone who is watching someone you love suffer? You have to do all you can do- you have to be aware and be patient. These are the two MOST important things you can do. Pushing someone to get out of their slump or making them feel bad about it is of no help to anyone, it may even be dangerous. A little nudge to go out or look at beautiful and happy things, and showing that you're there for them and love them unconditionally, this is all helpful. However, be aware that in the end, only the brain gets to choose.The brain gets to control the mood and thoughts of this individual. It really is like a demon taking over or being put in a hypnotic state. The person you once knew is under a spell of darkness. Until they are released, everyone is at risk. At this time, nothing is about you. What they do and say is probably not personal, their choices and feelings are not your fault, and if you can't "fix" someone, it is because they could not be fixed or did not wish to be. Depression is about the individual, it is so enveloping that anyone outside the individual is hardly present at all.
That is why awareness is extremely important in these cases. There are many types of Depressed people. Everyone expresses it differently and to different degrees. There are those who need to be addressed; who will do everything in the world to be heard and seen and loved. Then there are those who suffer quietly. Both types need help, but doing this boldly isn't always a good idea. Much like helping a stray dog who is nervous around humans, you can't just jump at them and scoop them away. Sometimes you have to ease them out with treats and kiss sounds. Other times, you have to accept that they'll never trust your hands. In this case, you just have to be on the lookout for changes in behaviour. The way they speak or interact with you, or if they interact with you at all! If suddenly this person seems to be in dangerous or harmful situations more often. If they keep "accidentally" getting hurt, or being put in risky situations, or spending more time with risky people, places, and things. If hobbies go ignored, responsibilities and usual habits go untouched. All these changes have the potential to be red flags. If the worst thing you can do is inquire or try to make this person's life a little easier and their worst response is frustration with you, I say it's worth it. If the person seeks seclusion, don't force them out, but do check in on them. If only a text or email or a random care package or letter in the mail.... Until you try, you don't know what will reassure this person or pull the demon out from them.
In this stage, the demon is more like a coma. The Depressed individual seems gone, but they can hear you and feel your presence. With enough persistence and care, it just might work. This may contradict what I said above, about the futility of your attempts to change a person. However, there is a difference. When you're showing you care, this is not an effort to help or save them, it is not insistent and rushed. This kind of expression is gentle and without a motive. You'll likely have a goal or intent, but when offering your hand, this should be empty of any purpose but to express a feeling of love without any strings or expectations attached.
All people experience Depression in different ways, some more obviously than others. But there are signs that a closer look can determine. If you want to make a difference and be the one who "caught them", it is possible. If you suspect someone is facing Depression to an extent that they need help, find a local resource, either a crisis hotline or online chat, or even a website with more information. If not for them, do it for your own understanding of the problem and 'what to do if'. Get informed, that's the best thing you can do before anything else. Knowledge is what will help you get through this difficult time.
Good luck and be well.