Updated

A Massachusetts woman charged with manslaughter after sending her boyfriend text messages encouraging him to take his own life has been dealt a setback.

An attorney for 20-year-old Michelle Carter asked a judge Thursday for funds to hire an expert to explain, at trial, the effects of an antidepressant.

Attorney Joseph Cataldo said both Carter and her boyfriend, 18-year-old Conrad Roy III, were taking Celexa. He said it has a warning that it may cause suicidal thoughts.

But the judge denied the request, saying Celexa's effect on Roy was "speculative." The judge approved funds, however, for the defense to hire an expert on adolescent behavior.

Roy was found dead of carbon monoxide poisoning in his pickup truck in Fairhaven. Carter was 17 at the time of Roy's July 2014 death.