hlocklearpart2062109_00_X17WM230.jpgHeather Locklear, who was hospitalized with a "medical emergency," has been "having a hard time" with drugs and alcohol, according to ET.

A source tells ET that Locklear was "out of control" at the time her sister called 911 on Thursday.

The source adds, "Heather became a different person on drugs" and that she's been in and out of rehab over the years. Locklear has also reportedly had a tough time dealing with her split from Jack Wagner.

A hospital spokesperson spoke to KCAL-TV on behalf of Locklear telling the station they "wanted everybody to know that she's doing well, she's fine, she's not in any danger, she's healthy."

Locklear's rep has yet to issue a statement.