singaporean a * star scholarship recipient xiangyu ouyang , 26 , is accused of slipping paraformaldehyde to several fellow students .
ouyang has confessed to poisoning two classmates , as well as herself , in what she 's called a cry for help .
she is charged with four felony poisonings -- which could carry 2 to 8 years -- and was expected to use an insanity defense .
ouyang won the prestigious scholarship in 2013 for her outstanding performance as an undergrad at imperial college london .