Here is a story I wrote about Rex abusing/using drugs. I kinda wrote it from my own experiences and hardships (I do not use drugs, but have friends and know people that do) so here ya go:

WARNING! There is use of drugs, alcohol and strong language. Do not read if you are young or oppose to these subjects.

If you are still here:

"Inner Demons"

Six took Rex to holidays and explained what happened. "Everything will be ok. His injuries are minor." Holiday told six. Six gave one last look at Rex and left so Holiday could do whatever she does best.
'There was more to this' Six thought. The way Rex froze, he had seen that somewhere before. Six figured he would ask more once Rex was up.

Rex finally woke up, even though he didn't really want to.

"Glad you're feeling better." Holiday announced when she noticed Rex was awake.

"I guess." Rex swung his legs off the table.

"What happened?" Holiday asked.

"What? The EVO?" Rex tried to play it off. "I lost."

"Come on Rex, you never admit losing." Holiday sat up on a table across from Rex.

"I...I just. It was the same EVO from the other day." His stomachs twisted in knots. He felt sick.

"Rex," Rex looked up "there are always going to be things we can't control. Bad things happen, it's a fact of life. But you can't let them control you. I know you're strong, you've gone through so much already, you can't just quit. What about Noah? Me? Six, Bobo? How do you think we feel?" The phone rang and Holiday went to answer. Rex stood up, but stayed for a little bit, thinking about what Holiday said before he left.
Six had waited out in the hall for Rex and when he walked out he asked

"Are you feeling better?" Six didn't want to push.

"yeah, I guess so." Rex didn't stop, forcing Six to catch up.

"so do you think you can train more tomorrow?"

"Sure." Rex wasn't really listening.

"Ok then..." Six waited for a reply but was left empty handed. Teenagers were harder to figure out than security pass codes.
When Rex was finally alone in his room he went to his single dresser and opened it. Inside he pulled out a bunched up napkin. He sat it on his floor and sat on his bed. He thought about its contents for a while before putting it back in its rightful place in his dresser.
For the next few weeks everything seemed fine. Rex was back to his self, mostly. Noah still had to beg for Rex to go out but once he was, they had fun. One night the nightmares relapsed and everything fell apart. Rex woke and sat up, hitting his head on the bunk above his.

"Shit." He spat through gritted teeth. The dreams still playing in his mind he shut his eyes tight, trying to make them go away.

"You're a freak!" They shouted "you don't even know who you are!"

"But..." Rex tried to cut in.

"Why don't you go get drunk again? I'm sure Holiday would love it! The way you hurt her, causing problems!"

"But I..." This time Rex stopped himself. He took the napkin out and opened it. Inside contained quite a collection of pain killers, anti-depressants, cough pills and more. Rex took a handful and sat the rest down. He swallowed and soon the voices subsided. The hurting and pain stayed, almost magnified. Rex laid back down, but really just leaned against the edge of his bed from the floor. He closed his eyes, but opened them when his stomach twisted and he felt like vomiting. The room twisted and he knocked most everything off his shelf as he stood. He made his way out to the hallway, slowly heading to the bathroom. Rex fell a few times and resorted to crawling. He never made it and ended up puking a few feet from his room. The white walls blurred together into a 2D world.
Holiday made her way to her office the next morning to find a pale Rex with bloodshot eyes laying in the hall. He had little spasms and small machines tried to grow from him as his nanites hopelessly fought the effects of whatever he had done. Holiday gasped and dropped her papers. She was at Rex's side instantly.

"Rex?" There was no answer. His eyes were open but he was unresponsive. Holiday checked his pulse and watched as he breathed. The rise and fall of his chest was slow and almost nonexistent. She called for help and got Rex to the lab, hooking him up to a heart monitor and various IVs. It took about 24 hours for Rex to open his eyes. Holiday was called to a meeting with White, there was no hiding this from the rest of the building.

"He's doing fine now, he woke up a little bit ago." Holiday explained to an outraged White Knight.

"We can't have some pill pushing teen working for Providence! Either you find a way to control him, or I will!" With that the screen flashed back to black and Holiday still standing there.