One source told TMZ.com her management team haven't been able to get in touch with the former child star in a month and attempts to get help her before she went under the radar had all failed.
Amanda has had a turbulent few months, including recently having her car impounded and her driving licence suspended while she faces charges of DUI (driving under the influence) and multiple accusations of hit and run.
The 26-year-old star denies she is responsible, saying she never drinks and drives, as well as claiming she is quitting acting, which could explain why she hasn't talked to her managers.
She said: "I am doing amazing. I am retired as an actor. I am moving to New York to launch my career. I am going to do a fashion line. I am not talking about being arrested for DUI because I don't drink, and I don't drink and drive. It is all false."
Despite her assertions, Amanda was again involved in two bizarre incidents earlier this week, locking herself in a store changing room for nearly two hours and refusing to come out and stripping off during a gym class.
An onlooker in the class said: "Amanda stopped to take her T-shirt off, revealing only a tiny, black, strapless push-up bra - not a sports bra.
"She then picked up her Louis Vuitton handbag and pulled out her makeup kit and started reapplying her lipstick and eyeliner while looking at herself in the large mirror in front of her."