PITTSBURGH — An 18-year-old man who allegedly asked police after his arrest if he could be held responsible for doing something while on medication was ordered to stand trial on a charge of fatally stabbing his ex-girlfriend.

John Mullarkey Jr., of Monroeville, stabbed Demi Cuccia, 16, on Aug. 15 and then slashed his own throat, police said. His attorney said the teen was taking Accutane, an acne drug that the U.S. Food and Drug Administration has linked to episodes of suicide and depression.

Allegheny County Detective Mike Kuma testified Friday that he communicated with Mullarkey using a message board while Mullarkey was recovering from his neck wound. Kuma said Mullarkey asked him, without prompting, about a medicated person being held responsible for his actions.

After the hearing, defense attorney Robert Stewart said he's not sure if he will use his client's use of Accutane as a defense at trial because, at this point, he's not willing to concede that Mullarkey stabbed Cuccia.

"But he was taking Accutane and if you just look on the Internet at the drug Accutane it has a significant history of causing side effects, including suicidal ideations and aggressive behavior," Stewart said.