I want to die.
This single, four-word thought was at the core of Twilight's existence. Every day, it would pop up in her head, at least once, usually more. She rarely had the energy to go outside for fresh air, so she was often shut in her library, windows closed, curtains drawn. No one really bothered visiting. Aside from Rainbow Dash crashing into the library, she didn't see her friends often. At first, she wanted to see them. She knew that talking with her friends would be incredibly beneficial to her slowly degrading mental health. But as time passed, she stopped caring. One month, two, no huge events demanded her presence with the Elements, and other social events hadn't come up to drag her out of her library and make her talk to ponies. Four months, still nothing. Once the library had been sufficiently cleaned, she "allowed" Spike to go hang out with Rarity, which kept him out of the library, and less likely to notice Twilight's worsening mental stability.
Twilight didn't cry when the depression threatened to drown her, nor when her anxiety threatened to crush her. She couldn't cry at all. She didn't feel sad when her depression came in like the tide. She felt nothing. She was just there. For a while, she was afraid of the numbness. She would try anything she could to feel something. She tried reading books to escape to somewhere else, hoping that she could feel something there. But that only lasted for so long. She tried overeating to feel shame and not eating to feel fear. But those tactics didn't work, and soon enough, she just stopped feeling hungry. Sometimes for days on end. Occasionally, her stomach would hurt enough to make her eat an apple, or some other insignificant piece of food, praying that she would just die of exhaustion.
Twilight paced around the library, not entirely conscious of what time it was or where she was, or if she was even awake at all. She was bored out of her mind, and nothing could satisfy her. She tried sketching something, but couldn't even get the first stroke straight. Her magic had grown unstable, and sometimes it would cut out entirely. Just last week, she dropped a cup of freshly brewed coffee on herself because of this. Now, with her magic barely able to be practical to use, she had gotten used to doing things manually, and quickly found out just how physically uncoordinated she was.
A knock pierced the silence, drawing a small measure of attention from the unicorn. She kept pacing, hoping that whoever was at the door would just go away and leave her to waste away as she'd been doing.
Another knock. This time a little stronger, a little more desperate. "Twilight, I know for a fact you're home," a familiar, crackly voice followed. "You haven't come out in three weeks. Open up!"
Twilight felt her heart pounding. She couldn't open the door. She couldn't let her friends see her like this. She couldn't let them find any hints that she had that four-word thought. She couldn't let them see that.
"Twilight, I may not be as strong as Applejack, but I can still kick your door down. Please just open up," Rainbow called.
Twilight swallowed the lump in her throat and called back, "I'm fine, just go away!"
A brief pause. "Even I can tell that's a lie."
Twilight cursed under her breath. "Please just go away, Rainbow."
"Not until you let me in."
"Rainbow, please just go away..."
"No, Twilight. This is not up for negotiation. You're going to let me in, and then we're going to talk, and only then will I leave you alone. Now for the love of Luna let me in already," the pegasus outside said. "We're really worried about you, Twi."
Against everything her anxiety was telling her, Twilight opened the door. Rainbow jumped a bit at the sight of Twilight. The unicorn's mane was frazzled and unkempt, matted and knotted to the point that Rarity would have outright puked at the sight of it. The rest of her fur wasn't much better, only spared the knotting due to how much shorter it was than the hair in her mane and tail. "Sweet Celestia you look like hell," Rainbow murmured on her way in.
"Thanks," Twilight hissed in response. Once she noticed Rainbow's saddlebags, she asked, "What's with the luggage?"
"Spike and Fluttershy are worried you haven't been eating. Spike noticed that the food's been ending up in the trash instead of in a stomach, and he asked Fluttershy what to do about it," Rainbow replied as she reached into her saddlebags and pulled out a pair of sandwiches. "So she made some sandwiches and told me to come make sure you eat."
"I'm not—"
"I don't give a shit. You're going to eat this sandwich," the pegasus asserted.
Twilight fell silent, trying to think of some way to get out of her current situation. Rainbow pulled out a pair of paper plates along with the sandwiches, and passing Twilight her sandwich. For a while, she just stared at it, praying that she wouldn't have to eat it, that she wouldn't have to put the effort into living that eating required of her.
I can't do this.
Another four-word thought, simple, but just as insidious as the previous: the sound of hope dying, of confidence fading out of existence, leaving Twilight void of light, warmth, and resistance. She lowered her head, listening to her stomach growl and feeling even more disgusted at herself for it. Her body was starving, begging her to feed it, but her mind refused to believe it. She didn't need food for what she planned to do. She needed to avoid food like the plague; cast it out of her home and forsake all temptations for it.
"I'm not leaving until I see you eat," Rainbow said.
"Why are you doing this?" Twilight murmured quietly.
"Because I care—"
"Why are you forcing me to suffer?" Twilight growled, a little louder.
"Twilight, stop."
"I just want to be left alone—"
"Twilight, please..."
"—so I can just stop existing—"
"I'M DOING THIS BECAUSE I'M SCARED!" Rainbow screamed. Tears began to roll down her cheeks, and she finally broke down into a sobbing mess.
Twilight stared at the pegasus. As she collapsed into a crying heap, Twilight began to feel something in her heart, strengthening with each shallow beat. Pain, the very thing Twilight had spent weeks trying to starve away, came forth again. Sadness wiped her eyes, and freed the tears that should have come out long ago. Fear finally sounded the alarms, alerting her to the gravity of the situation that she was fully responsible for.
Twilight picked herself up and moved closer to her friend, sitting back down next to her.
"Why are you doing this?" Rainbow asked softly between sobs.
Twilight looked away, whispering just barely audibly, "I want to die..."
Rainbow looked over to Twilight with puffy, teary eyes. But there was something else there; something more. Twilight couldn't quite recognize it, but she could sense it. Wordlessly, Rainbow lifted her wing and draped it over Twilight, allowing her to feel warmth again. Twilight finally broke down and cried, her prismatic pegasus friend remaining silent, knowing that more words would only cause more pain than was necessary.
"I am not okay," Twilight sobbed out.
"I know... Just let it all out..."
"I'm sorry..."
"I'm here for you."