Mississippi teen Carly Gregg was severely depressed and possibly hearing voices when she allegedly gunned down her own mother, psychiatrists testified at her trial Thursday — but one argued she committed a “diabolical” act that keeps her from meeting the requirements of an insanity defense.

“I used the word diabolical. And I stand by that word,” psychiatrist Jason Pickett said of the 15-year-old, who was caught on camera texting her stepfather “When will you be home honey?” from her mother Ashley Smylie’s phone moments after allegedly shooting the 40-year-old in the face on March 19.

The text was an apparent trick to lure her stepfather home — when he returned a short time later, Gregg allegedly fired a pistol at him and grazed him in the shoulder.

“When she did that, to me, that was very specific and diabolical. And that to me is not consistent with a dissociative spell, it is not consistent with psychosis, that is not consistent with mania,” said Pickett, who interviewed Gregg for over four hours after her arrest, according to WAPT.

“In my opinion, Carly does not meet Mississippi’s standard for insanity at the time of the offense and she knew the nature and quality of her actions on that day.”

In Mississippi, defendants can be acquitted on the grounds of insanity if it’s demonstrated they were unable to understand the severity or impact of their actions, according to Justia Law — which is what Gregg’s defense is trying to establish.

Other psychiatrists at the trial painted a picture of a girl who was suffering severe mental illness in the lead-up to the alleged murder — including one who insisted Gregg was hearing voices.

“She said she had been hearing one voice, a male voice, since she was young — maybe around five or six years old,” said Dr. Amanda Gugliano, who also interviewed Gregg after her arrest.

“She said she heard the voice every day, but it was always in the background and she was able to tune it out,” Gugliano said, explaining the voice Gregg told her about was a snide critic who would make comments about people.

On Wednesday, Dr. Andrew Clark testified that the voices in Gregg’s head had been intensifying leading up to the shooting, and that she experienced a mental break that day and has no recollection of the incident.

But other medical professionals who worked with Gregg disputed the claim about the alleged voices.

Olivia Leber — a nurse who worked with Gregg in January before the killing — said she never complained about voices, delusions, or hallucinations while she was being diagnosed with major depressive disorder.

And Rebecca Kirk — a counselor who also met with Gregg in January after her parents said she was having severe intrusive thoughts — testified that the girl insisted she was not hearing voices.

Gregg and Kirk met nine different times and even had conversations about “Crime and Punishment,” the Russian novel about a man who murders a woman and then becomes plagued by anguish and guilt. But during none of those sessions did Gregg exhibit anything that might indicate she was about to commit murder, Kirk said.

Home surveillance footage from the family’s home in Brandon showed Smylie and her daughter coming home after apparently taking their dogs for a walk. Gregg was seen shuffling about the house, and eventually followed her mother out of the frame before three gunshots and screams rang out.

The teen then returned to the view of the camera with something behind her back, and appeared to be deliberately facing the camera. Within moments she picked up her mother’s phone and sent off a text message.

Clark suggested the news of her mother’s recent discovery of the teen’s marijuana habit, coupled with the emotional turmoil she was going through, might have sparked a psychotic episode.

“For Carly, in particular, she so cared about her mother’s approval, so for her, this was a crisis,” Clark said.

The teen faces charges of murder, attempted murder and tampering with evidence — along with 30 years to life in prison if convicted.