The "very defiant" 47-year-old reality TV star apparently struggled in her attempt to get sober, as she "tried to leave and ended up coming back" to the undisclosed treatment center during her stay, another source told Us late last month.
Richards was reportedly absent from last week's filming of The Real Housewives of Beverly Hills' second-season reunion special, which will air later this year, due to being in rehab.
Richards' alleged alcoholism publicly came to light on Bravo's January 2011 broadcast ofThe Real Housewives of Beverly Hills' first-season finale during an argument with Kyle Richards, her sister and fellow The Real Housewives star.
During the heated confrontation, Kyle claimed Richards was an alcoholic who had previously rejected her family's attempts to convince her to enter a rehab program.
Richards was reportedly deeply humiliated by her sister's disclosure but nonetheless returned for the second season of The Real Housewives of Beverly Hills, which premiered in September.