Defense: Teen whose texts urged boyfriend's suicide was 'involuntarily intoxicated'

— -- Michelle Carter, the 20-year-old Massachusetts woman charged with involuntary manslaughter for allegedly urging her then-boyfriend to commit suicide in 2014, became "involuntarily intoxicated" from prescription drugs, a psychiatrist for the defense testified Monday.

Conrad Roy was 18 when he died in July 2014 of carbon monoxide poisoning after locking himself in his truck. The prosecution claims Carter, then 17, was reckless and caused Roy’s death by telling him to get back in the vehicle, even though he told her that he didn't want to die. But Carter maintains her innocence.

In court Monday, Dr. Peter Breggin, a psychiatrist and expert witness for the defense described Carter as being "psychotic, delusional, and out of touch" after learning that Carter spoke to Roy's parents following the incident and didn't mention anything about his death.

Breggin testified in Bristol County Juvenile Court that this behavior was because Carter became involuntarily intoxicated, and that in her mind, encouraging Roy's suicide was being "helpful."

According to Breggin, Carter was on Celexa, an antidepressant prescription drug that the Associated Press reports can target the brain's frontal lobe, which controls decision-making and empathy.

Prosecutor Maryclare Flynn said in opening statements that Carter "used Conrad as a pawn in a sick game of life and death for attention." The testimony of several of Carter's classmates last week supported the prosecution's argument that Carter didn't have many friends, and pushed Roy to suicide to get more attention from the friends she was pursuing.

According to a testimony from last week, on July 12, 2014, the day of Roy's suicide, Carter texted a classmate, "He just called me and there was a loud noise like a motor ... I heard moaning ... I stayed on the phone for like 20 minutes and that’s all I heard. ... I think he just killed himself."

Testimony regarding text messages from Carter’s cell phone was also heard in court. On July 14, according to testimony, Carter texted a classmate, "I do blame myself, it's my fault. I was talking to him while he killed himself."

On July 21, the teen texted a classmate that Roy's mother told her that detectives were going through Roy's belongings. "They have to go through his phone and see if anyone encouraged him to do it," Carter texted. "I’m done. His family will hate me and I could go to jail."

In September 2014, Carter texted a classmate, "I could’ve stopped him." She texted that she and Roy were on the phone the day of his suicide in July when Roy "got out of the car ... he was scared."

Carter wrote that she "told him to get back in."

The defense argued that Carter had tried before to talk Roy out of harming himself, and the defense pointed to a conversation where Roy told Carter he regretted dragging her into his plans to kill himself.

"It is not a homicide," lawyers for Carter said. "The evidence of the texting is overwhelming that Conrad Roy was on this path to take his own life for years."

The defense added, "Even if somebody supports another individual in a suicide, it doesn’t create a homicide."

Carter waived her jury trial, leaving her fate in the hands of the judge. Carter is charged as a youthful offender, which means that even though she was a minor at the time of the alleged crime, she is charged as an adult. If convicted, she could face 20 years in prison.