Does Taking Ambien Really Cause Memory Loss?

On tonight's episode of Big Little Lies, Celeste (played by Nicole Kidman) goes to court over her custody battle, and her memory is called into question. In past episodes, it was revealed that she has been taking Ambien to help her sleep, a habit that Mary Louise (Meryl Streep) doesn't approve of. After all, she told her mother-in-law that she drove her car off the road while in an Ambien daze.

When a lawyer asks Celeste if she recalls taking home men other than bartender Joe (Christopher Bakus), she says no, before flashing back to a forgotten sexual encounter in her bed. "Well once," she says. Then, the lawyer asks if her kids have seen men other than Joe around, suggesting that one of her twins had an interaction with someone. This is when Celeste admits that sometimes she takes Ambien, implying that it's possible she forgot. But it's not clear if that was just a hypothetical question, or something that actually happened (Mary Louise’s face suggests the latter). Celeste can't seem to remember, either.

The thing is, amnesia is a short-term side effect of taking Ambien, which is known by the generic name zolpidem. Like other benzodiazepines drugs, zolpidem stimulates and binds to GABA receptors, which send messages to the central nervous system, explains Tom Roth, Ph.D., director, Henry Ford Hospital Sleep Disorders and Research Center. When you take Ambien, the drug essentially slows activity in your brain to a point where you can fall asleep. Zolpidem decreases the amount of time it takes to fall asleep, increases sleep duration, and causes fewer awakenings throughout the night, explains Q. Afifa Shamim-Uzzaman, MD, MD, director of the Sleep Disorders Center at the Ann Arbor VA.

"The problem with the drug is it binds to other [brain] areas as well," ones that are are responsible for different functions besides sleep, Dr. Roth says. This can lead to specific sensations, such as amnesia and impaired coordination, he says. Other common side effects include a "drugged feeling," nausea, and headaches, according to MedlinePlus. Most of the time, that isn't a big deal, because in theory you'd be asleep after taking Ambien and not experience any other effects besides sleep. Ambien also has a high half-life, meaning it wears off relatively quickly, and you rarely experience a "hangover" effect. "Where you get into trouble is when you're not asleep," he says.

If someone takes zolpidem, but doesn't sleep a full eight hours, it can lead to "significant consequences," Dr. Shamim-Uzzaman says. "Sleep-driving" as well as sleep-walking, talking, and eating, while not fully awake have all been reported, she says. If someone has also been drinking alcohol or taking other central nervous system depressants, these effects tend to be more pronounced, she adds. And the crazy thing is, people won't remember doing it the morning after.

Now, some people take Ambien to purposefully stay awake and enjoy the out-of-body effects, although that isn't the way the drug is supposed to be used. Specifically, some say it lowers their inhibitions to have sex, and even makes them feel more aroused. However, given Ambien's effects on your memory, you could see why this off-label use could be problematic. "Zolpidem should only be taken under the close supervision of a physician and for short-term use," Dr. Shamim-Uzzaman says.

Without knowing exactly why, when, or to what extent BLL's Celeste has been taking Ambien, it's tough to extrapolate whether or not she really remembers having sex with these men or not. Based on the way the season has unfolded heretofore, it seems like Celeste's Ambien use and overall mental state might be an important plot point for the rest of the season.

It's also worth noting that Ambien isn't the only substance that we know causes these sort of symptoms. All sedatives, including alcohol, have the potential to cause amnesia, Dr. Roth says. But Ambien won't fundamentally change your personality or sense of self. "In other words, if you're a 'go to church every Sunday' kind of person, will this make you a killer?" he says. "No, not gonna happen. But, it is a great excuse." Or, in the case of the Monterey Five, a lie.