What is wrong with him?

What illness or drug could cause these symptoms:
extreme weight loss
loss of appetite
mood swings
increased acne (where there was none before
self-injury (hitting yourself HARD)
lying
hallucinations

Thank you!!!

Sounds like Meth, and it can make you age 20 years in just a couple of months. Either get him treatment or run for your life. They say that it's almost impossible to get past this, it's all a down hill spiral. I would move across town, or across States to get away from that stuff. It's a very dangerous game that he's playing, one with no escape!!!

Meth

Crack, cocaine, weed, lsd (acid) any drug can cause those symptoms

My guess, is he is suffering depression probably by a chemical imbalance. Have him see a good specialist in this field. I had too. I have recovered.
My God bless you both.

Steroids.... especially if he is an athlete.

All of these symptoms defiantly point to meth please get him help before its too late!
good luck

This absolutely fits the profile for meth abuse.

This could have any number of causes including illicit drug use (methamphetamines, anabolic steroids, etc) or some form of mental illness causing decreased hygiene.

This person sounds as though they are not only a danger to themselves but could well be a danger to others. I suggest that you seek immediate medical evaluation and be prepared to do whatever is necessary to ensure their safety and your own.