Patton Oswalt’s wife, Michelle McNamara, died abruptly in her sleep at the age of 46 about a year ago, and the comic has revealed the cause of her death.

The actor and comedian told the Associated Press on Friday, “We learned today that the combination of medicines in Michelle’s system, along with an illness we were unaware of, proved devastating.”

Oswalt explained that the pair, who married in 2005, had “no notion” she had a disease that caused her arteries to constrict.

According to Oswalt, the mother of one died in April of 2016 due to the impediments, as well as the fact that she was taking Adderall, Xanax, and the pain medication fentanyl.

According to Lieutenant David Smith of the Los Angeles County Coroner’s Office, who talked with the Associated Press, McNamara’s cause of death is still unknown.

In an October interview with The New York Times, Oswalt detailed his final evening with his wife. He believed that she may have overdosed on medication by accident.

McNamara, who was working on a book about a serial rapist and killer at the time, was working long days and nights and could not sleep due to her anxiety and nightmares that kept her awake at night.

Oswalt told her to spend the night in bed and “sleep till you wake up” because he was concerned about her health. McNamara took a few Xanax pills before going to bed on April 21 and did not wake up again.

Oswalt remembers getting up early the following day to assist in getting their seven-year-old daughter Alice ready for school, packing her backpack, and getting her out the door. He remembers buying an Americano coffee on the way home and then leaving it on McNamara’s bedside table at around 9:40 a.m.

He checked back on his wife after a few hours to see if she had risen. She stayed in bed and showed no indications of life. The responding paramedics at the scene confirmed her death. Oswalt stated that he believed the Xanax was to blame for the death, even though the coroner’s office had not yet determined a cause.

In December, the man, who had only one child at the time, penned an emotional piece for GQ magazine on his first year as a single father.

“This is the first time I’ve ever parented my child. I failed to return the school forms. I’ve neglected to stock the refrigerator with stuff she likes. Unfortunately, I don’t have any more socks for her. There are no more socks available for me to wear. It was painful, and it happened frequently, yet life carried on. The world continued to revolve. I apologized and quickly repaired the problem before continuing to fumble my way ahead, “Oswalt wrote.

“I’m going to keep going forward, looking stupid and awkward and unskilled at first, then ultimately getting it, until the next jolt comes, and the next level collapses out from under me until there are no more floors,” he said.