This story isn't exactly mine to tell. It's someone else's. All I can tell you about is my experience.
Their are many different types of mental disorders: Schizophrenia, Dissociative Identity Disorder, anxiety, and most commonly, depression, to name a few.
Depression (major depressive disorder or clinical depression) is a mood disorder. It causes severe symptoms that affect how you feel, think, and handle daily activities. It's extremely common and affects about 14.8 million American adults in a given year. There are treatments for depression and most of them include therapy and/or medicine. There is help out there for those who suffer from this disorder.
My experience with depression is slightly different. I have never suffered or have been diagnosed with depression. However, I have experienced it.
I'd like to start off by saying that depression comes from no fault of your own. You can't help it and it puts you in such a funk that you can't even comprehend what it feels like to not be depressed. Loving someone who feels this way is extremely hard for you and for them. Most of the time you constantly want to be around them and help them. You want to do everything you can do to make them happy. You want them to know that they're loved and worth it. You try to drill into their minds that they are important. Unfortunately, depression creates a whole new person; it changes their mindset. Loving someone with a disorder like this slowly sucks the life out of you as well. It doesn't happen intentionally, but when you love someone so much, their happiness becomes your happiness. And when they aren't happy, neither are you. You see them sitting at their desk staring out the window and you just know that the depression has taken over their thoughts. You see them laying on the bed and staring up at the ceiling and you wonder: are they contemplating suicide? You look at them and smile, but the smile that you get back is nothing like the smile you received three months ago. They cry to you, ask what's wrong with them, and ask when they'll finally be happy. All you can manage is a sob back and saying "it'll be okay."
Sometimes the depressed individual can't even fathom that they deserve to be helped, and sometimes your willingness just causes them to be irritated. Your attempts almost feel smothering. Unfortunately, no one wins in this situation until they decide to commit to getting help.
Loving someone with a mental disorder is the hardest thing a person can do. It's emotionally draining and gut-wrenching. Nothing is worse than watching the person you love destroy themselves from the inside out. Sometimes the depression, or anxiety, or whatever they're dealing with gets so intense that they remove everyone from their life and you're just left wondering, "what did I do wrong?"
Nothing. You did nothing wrong.