I took myself to a mental hospital, Las Encinas Hospital, in Pasadena, CA some years back when I was going to end it (but my cats saved my life). I was there for 3.5 weeks. If you DO mention you want to end your life, (or hurt others), they will put you on a 50/50 (72-hour hold) in a "white room" which is a horrible place where you don't want to be - everything is taken from you, even your shoe strings.
When you go into a Mental Hospital, into the general part of the hospital you'll probably have a roommate (of the same gender) and they'll ruffle through all your bags looking for drugs, phones, etc. (so if you want your cell phone and charger, be sure to stuff them in two pairs of sox and don't leave them out and leave the phone on no-ring, and re-charge at night.
They usually will assign you a new Psychiatrist and a new Psychologist or Therapist there at the Hospital. The food was great where I was (one of those that the famous people go to and 100 year old arboretum), but I hated the groups and some of the workers sucked, one nurse I became friends with told me things she shouldn't have about how things work, a well known drummer I made friends with (I played pro percussion) would just leave the facility in his pajamas (he was there for the drug program, in a different area, but we all ate in the same place (really great food!), but he walked to Target in his P.J.'s and called his wife from the Candy section (her name is Candi) and came back telling us about it - others would leave to get beer, etc.; one guy had a limousine pick him up to go see his famous dad's concert - it was a real "harsh" ha-ha-ha place. Dr. Drew's office was there, I met him only to ask where a certain Therapist's office was my first time seeing her and he was pretty darne'd rude!
Anyways, The hospital I went to was ONLY fun at mealtime and in between the groups. They even had washers and driers so we could wash our clothes. Anyways, it was a very "special" hospital, but it's also where I got misdiagnosed by the bad Psychologist and very bad things happened.
I also tried to stop my friend from getting ECT and actually opened the door to that room as they were turning her table upside-down to get ready to do it, and I said "NO MARY, DON'T DO IT, STOP! TELL THEM TO STOP!!" and they yelled at me "YOU CAN'T BE IN HERE!!" and slammed the door in my face. When she came out, she didn't remember me for a few days. Same with another friend I made there - she had no idea who I was. ECT - Don't DO IT!! PLEASE!! Don't EVER let them talk you into it!
Anyways, I just wanted to give you some insight as to what being in the hospital is like. If you really DO feel suicidal then DO let them know, but if you're not, be sure NOT to let them know so you don't have to suffer in that horrible small building with the most highly drugged people and eating cold food and doing absolutely nothing all day.
Most of all ~ Be Well <3