On Monday, actress Roseanne Barr tweeted an incredibly racist joke about Valerie Jarrett, a former aide to President Barack Obama. After the barrage of criticism that followed, even after her half-hearted apology, Barr shifted the blame to the sleep aid drug Ambien, suggesting it had influenced her behavior. While Ambien does have a proven track record of messing with the brain, there’s not much evidence to back up Barr’s excuse.

In a now-deleted tweet, Barr wrote: “It was 2 in the morning and I was Ambien tweeting-it was memorial day too-i went 2 far & do not want it defended-it was egregious Indefensible. I made a mistake I wish I hadn’t but…don’t defend it please.”

Anyone who’s taken Ambien (zolpidem) knows it can mess with your behavior in some weird ways, and while there’s some speculation about its “truth serum”-like abilities, there’s no evidence that it can make someone say things they don’t already believe in. Zolpidem, a sedative-hypnotic drug, belongs to a class of sedatives called “Z-drugs” that act like benzodiazepines — Valium, Xanax, and so on — but are not actually benzodiazepines. That is to say, zolpidem works by slowing down brain activity to help induce or lengthen sleep in patients who suffer from insomnia. This slowed activity can result in accidents and other strange nighttime behaviors.

ambien
Ambien is normally used as a sleep aid.

Researchers have documented sleep walking, sleep eating, and even sleep driving in patients on zolpidem. They’ve also noted an increased risk of injuries, possibly from impaired motor skills as a result of the drug. And even though Barr is just one of a handful of public figures who have said weird shit under the influence of zolpidem, her comments were harmful enough to trigger a response from the pharmaceutical industry. Sanofi, the company that manufactures Ambien, tweeted on Wednesday morning about how the company’s drug has not been shown to produce racism.

It’s pretty clearly a public relations move and a light troll, but the point is clear: Even if zolpidem can cause nighttime accidents, any interpersonal drama induced by the drug is likely already lingering beneath the surface. Barr has clarified that she blames herself, not the drug, for her words.

In this case, the clear implication is that zolpidem didn’t cause Barr to tweet a racist joke but that it lowered her inhibitions enough to make her think it was a good idea to tweet a racist joke. In that sense, she’s experiencing something a lot of people have probably experienced after a night of drinking or taking drugs: the negative consequences of telling someone what you really think about them.

To be fair, the history of so-called “truth serums” is a lot less clear-cut than the movies would have you believe. Just because someone’s inhibitions are lowered doesn’t necessarily mean they’re telling you the truth. There’s a long and troubled history of law enforcement officials using truth serums to extract confessions even though people under the influence of such sedatives are highly suggestible and have often been found to just say what they think someone wants to hear.

There’s not enough formal research on zolpidem’s effects on people’s behavior to say for sure what its role is in suggestibility and truth-telling, but in a few recent instances it did seem to encourage public figures to get weird in public. In June 2017, for instance, SpaceX CEO and newly revealed enemy of journalism Elon Musk tweeted about his night.

Musk’s reaction to the drug was pretty vanilla by comparison. Perhaps more memorably, way back in 2003, then-Secretary of State Colin Powell gave a bizarre interview about Ambien in which he almost seemed to be under the drug’s influence in that very moment.

colin powell ambien
Colin Powell talks about Ambien while seemingly on Ambien.

In short, it’s not wrong to say that zolpidem can make people act weird and overshare. But does it make you say things you don’t mean? The evidence suggests not.


See also: Why You Can’t Read in Your Dreams