'Devil on Trial' Shock Reveal—Can Sleeping Pills Really Mimic Possession?

In Netflix's The Devil on Trial, released Tuesday, viewers were introduced to the story of David Glatzel. In 1980, at the age of 11, Glatzel was allegedly possessed by a demon, which was exorcised with the help of famed paranormal investigators Ed and Lorraine Warren.

Although Glatzel's story has been adapted several times for the screen, including the 2021 movie The Conjuring 3': The Devil Made Me Do It, the documentary is the first to speak to all three of the Glatzel brothers—David, Alan and Carl—and get their side of the story.

Even now, David Glatzel is convinced that he was possessed by a demon as a child. However, his older brother, Carl, has never believed it.

In The Devil on Trial, the now 57-year-old reveals that while cleaning out his mother, Judy Glatzel's belongings after her death, he found evidence that she had been drugging her family with the sleeping aid Sominex.

Carl believes that his mother used the drug to control her three sons and their father, sneaking the drug into their food. He also believes that the side effects of Sominex are the real cause of his brother's supposed possession, citing "mood swings, weight gain and hallucinations" as side effects of the drug.

"At the end of the day, if everybody's tired and exhausted, guess what? Everybody's gonna rest and sit down. There's no problems," Carl said.

But can Sominex really mimic demonic possession? Newsweek asked an expert.

'Hallucinations Have Been Reported'

The active ingredient in Sominex is diphenhydramine hydrochloride, a sedating antihistamine that can help people to fall asleep. It is used to treat short-term sleep issues, such as insomnia, along with relieving allergy symptoms.

Dr. Rami N. Khayat, the medical director of UCI Health Sleep Medicine Services and a specialist in pulmonology and sleep medicine, says that diphenhydramine hydrochloride can cause hallucinations, although the dose has to be very high.

"Toxicity can occur when a dose that is more than 10 times the dose in over-the-counter pills is used," Khayat told Newsweek. "In these cases, cardiac arrhythmia, delirium and hallucinations have been reported."

Sominex and other medications containing diphenhydramine hydrochloride are only meant for short-term use. If taken regularly, users can build up a tolerance to the drug, making it less effective. Short-term side effects include dry mouth, confusion, memory issues, balance problems, blurred vision and urinary retention.

"There are no studies evaluating the safety of long-term use of these sleep aids and the potential for serious side effects from long-term use cannot be ruled out," said Khayat.

"Additionally, individuals with co-existing problems such as eye disorders, prostate disorders and heart conditions may be more prone to the side effects of these antihistamines with long-term use."

'Her Bowl Was Always Separate From Ours'

In The Devil on Trial, Carl said that he and his wife were sorting through his parents' belongings after his mother's death in 2011 when he made the shocking discovery.

"My mother wrote down everything. She had OCD," he says in the documentary. "It'd be on a piece of paper, a calendar, whatever, she'd write notes down. On this one note, it said, 'Well, the family had their medicine tonight, and everything was good.'"

They looked into the medicine in more detail and said they discovered that his mother was putting Sominex into their meals.

"She's been giving it to the whole family for quite a long time," Carl said. "I remember my mother serving us dinner. Her bowl was always separate from ours."

'She Didn't Go to Church Until All This Stuff With David'

His father, Carl Glatzel Sr., also never believed that his son was possessed, although staunch Catholic Judy Glatzel appeared convinced, eventually contacting the Warrens about her child's odd behavior.

In The Devil on Trial, Carl accused his mother and the Warrens of putting the possession idea into his brother's head through the power of suggestion. Instead, Carl believes that his brother was suffering from a mental health issue.

"My mother had her agenda," he said. "In front of people, she'd try to portray herself as a holy roller, but that was not even close to reality. She didn't go to church until all this stuff with David."

He recounts, at the age of 15, watching Ed and Lorraine Warren sitting at the kitchen table and telling his younger brother and mom how a possessed person would act.

"They were like saying, 'Well, he can start cursing at you, spitting at you,'" Carl recalls. "He'll grunt and growl like a savage."

"And my concern was, why talk about the subject when we're sitting right there? They wanted to make sure, you know, we heard it, and we did. Like you're leading him on what to do," he said.

When Judy attempted to restrain or calm down a "possessed" David, he allegedly would not relent. However, when his father tried, he'd obey immediately.

"You hear slap, 'get over there and sit down,'" Carl said. "And sure enough, the devil sat down and was very quiet."