The psychiatrist for a 4-year-old Massachusetts girl whose mother is accused of giving her a fatal prescription drug overdose acknowledged in the woman's murder trial that she repeatedly increased the dosages.

Dr. Kayoko Kifuji said Monday she increased the drugs after Carolyn Riley reported her daughter was aggressive and had trouble sleeping. She testified at Riley's murder trial under a grant of immunity from prosecutors.

Carolyn Riley is accused of deliberately overmedicating her daughter Rebecca to keep her quiet. She claims she was following the doctor's instructions and that Rebecca died of pneumonia in 2006.

Kifuji had diagnosed Rebecca with attention deficit hyperactivity disorder and bipolar disorder before she was 3 years old. Kifuju has said she did nothing wrong in treating the child. Rebecca Riley's estate has sued Kifuji.