Efforts to get murder charges against a teenager accused of choking his mother to death reduced Tuesday were denied, even after testimony that he blacked out during the incident.

Patrick Gibson’s lawyer, Leanne Chancey, wanted charges reduced to involuntary manslaughter but was ultimately denied, Channel 2 Action News reported.

“I don’t believe that there’s any evidence that he intended to kill his mother,” Chancey argued in court.

While the 15-year-old admitted to choking Faith Haynes to death, the Gwinnett County Medical Examiner’s Office ruled her death undetermined, citing no visible marks or bruises, Channel 2 reported. The medical examiner is waiting on blood and drug tests to return.

According to police, Haynes and Gibson, who is mentally ill, got into an argument at the Oakwood Vista Apartments near Norcross about him taking his medication.

The effort from his defense to get the charges reduced.

“He tried to walk outside to discard the medication. At that point, Faith grabbed him by the shirt and he turned around and blacked out and woke up to her not having a pulse,” Gwinnett County Detective Larry Williams said in court.

At the time of the incident, Gibson had just returned home after being under the care of the Division of Family and Children Services, Channel 2 reported.

Gibson’s family told the news station he has Asperger Syndrome. Chancey believes Gibson’s mental disorder led to the incident.

Gibson is charged as an adult in the Jan. 31 incident. He remains in the Rockdale Regional Youth Detention Center. Gibson also faces an aggravated assault charge.