People involved in one-night stands often have different perceptions of how an evening's encounter went, but in a Florida case this week, differing accounts landed one man behind bars.
Yehisson Acevedo, 29, was ordered to remain at the Orange County Jail on charges of sexual battery and burglary, according to a report from the Orlando Sentinel. Acevedo was accused of raping a woman who was under the influence of zolpidem -- the generic form of Ambien, a powerful sleep aid -- and alcohol.
But Acevedo claimed that the woman, whose name has not been released to the public, was cogent and initiated contact with him at a 7-Eleven, inviting him back to her house for a drink. The woman said she did not remember the events of the previous night upon waking in the morning.
The case brings to light the dangerous side of sleep aids, which, when misused, can leave people vulnerable to the actions of others as well as to self-neglect.
"Whether or not this person is responsible for a crime depends on whether they are really in a state of understanding the consequences of their behavior or not," said Rosalind Cartwright, chairman of psychology at Rush University in Chicago and a longtime sleep disorder researcher. "And with Ambien and alcohol, no way."
The Orlando Police Department reported that the woman drank a bottle of wine, then took zolpidem just after midnight. She said she did not recall going to the store or anything else she did until she awoke naked in her bed in the morning.
Zolpidem, a prescription sleep aid, has strict label instructions mandated by the U.S. Food and Drug Administration to avoid alcohol use while taking the drug.
On its own, zolpidem can have side effects that include amnesia and sleep walking. Mixing the drug with other drugs or alcohol can exacerbate the side effects.
Even caffeine or a loud noise during sleep can have adverse effects for those taking sleep aids like Ambien, causing someone to rouse into a half-sleep, half-waking state.
But it may not be obvious when people are under the influence of sleep aids and other substances.
"If this was a [drug]-induced, sleep-walking event, they are partially asleep and partially awake, though they look as though they are perfectly functional," Cartwright said.
While spatial-visual perception is active in a sleep walker, the prefrontal cortex, the part of the brain responsible for complex thought, decision-making and facial recognition, remains "asleep."
Lacking these functions, people under the influence of sleep aids like Ambien may behave in unusual ways. They may become socially uninhibited and aggressive. They can walk, talk and drive in many cases. They are capable of being sexually stimulated. They could become violent and attack loved ones if they do not recognize them.
"Research shows that people can and do engage in behavior they don't want to [or wouldn't ordinarily do] and, possibly, can be taken advantage of," said Michael Mangan, a psychologist and faculty member at the University of New Hampshire, Durham.
Cartwright said much depends on how much zolpidem and alcohol was in the woman's system when she awoke to go to the convenience store. Typically, such episodes occur in the first three hours of sleeping after taking medicine. It will also be important to determine whether she had a history of sleep walking.
But Cartwright pointed out that, even if the woman awoke and acted in full consciousness, the combination of drugs and alcohol in her system could have precipitated the odd behavior and amnesia.
"And for that [scenario], we have absolutely no experimental evidence at this point," Cartwright said, referring to the lack of data on people with no background in sleep walking who might mix sleep aids and alcohol.
There are some signs that a person taking sleep aids is not completely lucid, including having a blank face and stare and being unable to answer questions well. But if their basic motor functions appear normal, it can be difficult to tell a person who is half-asleep from a person who is fully awake.