I put my mother in a pysch. hospital and now i cant find her. Any advice?

How long since you had any contact?

Try the Court in the County the facility was in. Ask if there were any filings for State guardianship for Mom.

I am guessing you didn't live near her? You didn't talk to her daily? I would think the move took a few days to empty the place. I agree, call your State Ombudsman.

I echo Glad's query.   If you were listed as kin on the intake forms, you should have been notified.   If you weren't, there may not even be any record of your being related.

Call the state mental health office. They should know where the records for a closed facility are kept.

Did the court appoint a Guardian? Or are you her Guardian?
The State Ombudsman should look into this.
Who is rep payee for her Social Security? They should be able to tell you where the check is going.
And out of curiosity did you ask the police to search for her, technically she is a "missing person" they might be able to do a search much faster than you can.
You also mention she was in Assisted Living, do they have any knowledge of where she is, she must have had belongings that would have been sent to her with any permanent move.
And curious why she has not contacted you....

Contact the state's ombudsman's office.

Why weren't you notified of a move? That is very strange. Contact the Department of Human Services for assistance.