Depressed 20 year old

My son was a fun,out going boy when he  was in high school.  He was an athlete involved in many sports.  Upon entering his freshman year in college he took a turn for the worst.  I knew that he periodically smoked pot but it was never a constant problem.  He was able  to carry out his responsibilites.  Please don't think I consider underage drinking or any kind of marijuana use ok, believe me I  have talked  to all my children about the dangers of drugs/alcohol at an early age. When he came home for Christmas break 2 years ago he got into a fight at a party and broke a kids jaw in 2 places.  This is still not settle but it looks like he will get probation. My problem is he sleeps all day and is up all night.  He sleeps 16 hours a day.  He won't work.  He got an underage possesion of alcohol charge in which he had to attend 90 hours of community service in which he did 16 hours.  He received a letter from the courts stating that he hasn't completed his 90 hours in a timely manner so he has to go to court on Dec 21st.  I have told him for the past month that he has to attend his community service which is literally 1 block away from the house.  He has to work at the cities public works department.  He just sleeps, and sleeps and wouldn't get up.  He finally went this morning because the letter stated that a number of things could happend if he didn't complete the 76 hours by his court date of Dec 21st an one of them was incarceration.  
My question is:  Is my son clinically depressed or does he have a defiant disorder.  He has no goals, plans or motivation to do anything.  He doesn't talk to me and when he does, he's verbally abusive, tells me I'm constantly on his back.  
  He has no problem visiting his friends who go to ivy league school, and state colleges in the area.  I would think that he would be embarrassed to hang out with his childhood friends when they are all functioning and working to succeed.  
  Please tell me what my next step should be.  This has been 2 years of this.  I consider daily of throwing him out.  He expects jobs, to come to him, and won't go back to school.

Please advise

Cindy

[Venora Moonwind]

Unfprunatly this is something he needs to do to get help for himself. although If it were me I waould lay down the law ,either he gets help or he needs to move and I would no longer support.It is sad  but I had to do this with my oldest daughter so she moved out and about 6 months of being on her own she finnally got help.He may be depresse or he may be more heavy into the drugs than you know. either way he has to choose help. you can tell him what he needs to do but it will be ultimatly up to him to choose. you and your son are in my prayers.let me know how things progress.
Love Venora