TMZ has learned that Paris Hilton suffers from extreme Attention Deficit Disorder (ADD) and claustrophobia, and these conditions may have triggered the Sheriff's decision to spring her from Lynwood Jail last week.

We're told Hilton is taking Adderall for her ADD. Although our sources were not specific, we're told Hilton was not receiving all of her medications at Lynwood. As a result, Hilton was having severe panic attacks in jail. There were times she was so debilitated, she could not push the panic button in her cell.

As for how she's doing today, she's depressed but not really crying. She has a pencil and a pad of paper and she's spending her time writing down her thoughts. We're also told she's losing weight -- although she's no Nicole Richie.