On Saturday, Donald Trump suggested that Hillary Clinton take a drug test before the third presidential debate, which is scheduled to take place on Wednesday, October 19. But Trump’s erratic behavior and rambling speeches have sparked rumors an allegations of the Republican candidate’s own alleged drug use at least since July of this year.

Is there any truth to the rumor that Donald Trump uses drugs? Here’s what you need to know.

1. Trump Claims That He Lives a Drug-Free Lifestyle

Despite the fact that his business ventures have included selling Trump-branded wine and vodka, Trump himself said that he has never consumed alcohol — or smoked cigarettes or ingested recreational drugs.

“If you don’t drink and you don’t do drugs, your children … are going to have a tremendously enhanced chance of really being successful and having a good life,” Trump has said. “The world is so tough and it is so competitive that you can’t put yourself, as a child, or even as a parent, if you want that child to be successful, at a disadvantage of letting them drink or letting them take drugs because it is not going to work.”

2. His Brother Was an Alcoholic

Trump’s older brother, Fred Trump — called “Freddy” — was an alcoholic who died in 1981 at the age of 43, of symptoms reportedly cause by his excessive alcohol intake. The experience taught Donald Trump the dangers of subtle abuse, he has said.

“I’ve watched people and I study people and I had, in particular a great tutor on this, but I look and I see what it does to people when they lose control, and a lot of times they lose control,” Trump said, citing the heartbreaking story of his brother’s death as his motivation to abstain from alcohol.

3. Allegations of Trump’s Drug Use First Surfaced 24 Years Ago

Donald Trump challenges Hilary Clinton to a drugs test before next debate https://t.co/egQiOI9579 pic.twitter.com/tkuaMNFvcW — David (@firetrevs_blog) October 16, 2016

Despite Trump’s claim that he lives a clean, drug-free lifestyle, rumors that he abused certain types of drugs have circulated for more than two decades. In a February, 1992, Spy Magazine story, investigative reporter John Connolly unearthed a medical record that appeared to show that Trump had visited a New York doctor named Joseph Greenberg who, Connolly reported, was a physician to the stars known for prescribing diet drugs to celebrities — including Trump, Spy Magazine reported.

According to the story, which was revisited by the site Gawker this summer, Greenberg diagnosed Trump with “metabolic imbalance,” which despite not being an recognized medical condition, gave Greenberg a pretext to prescribe Trump a drug called Tenuate Dospan, or diethylpropion, which according to the site Drugs.com, “may impair your thinking or reactions… (and) may also cause restless feelings that can hide the symptoms of extreme tiredness.”

In other words, the drug acts like an amphetamine.

The medical site WebMD says that patients should not use diethylpropionm for more than “a few weeks at a time.” But according to the findings in Connolly’s 1992 story, Trump may have used the drug for a period of at least three years, from 1982 to 1985, the period during which he was Greenberg’s patient.

4. More Allegations Of “Cheap Speed” Use Surfaced This Year

Noted Former Cocaine User Carrie Fisher Says Donald Trump Was 'Absolutely' On Coke https://t.co/ZZsuMU8faS pic.twitter.com/CMxhfX0F88 — Esquire (@esquire) October 11, 2016

In July, Gawker reported what it called “a rumor” that Trump’s abuse of amphetamine-like diet pills did not end in the 1980s,, when he stopped seeing Dr. Greenberg.

According to Gawker reporter Ashley Feinberg, publishing the piece on July 1, “according to our source, the Donald Trump of today is on a diet drug called phentermine — and has been since at least April of 2014.”

Phentermine is also known more informally as “Fen-Phen,” which combined the drug with another, fenfluramine, and was marketed as a “miracle” weight loss drug. But Fen-Phen was pulled from the market by the Food and Drug Administration in 1997, after it was found to have potentially deadly side-effects, damaging a user’s heart muscle.

5. Trump’s Bizarre Sniffing Habit at the Debates Sparked New Allegations

Every Donald Trump Sniff At The 2nd Debate (original)★☆★READ THIS BEFORE COMMENTING★☆★ I just kinda got bored and made this supercut haha. One heck of a year 2016 has been, ya know? ★☆★Help Me Get to 2500 Subscribers! http://bit.ly/1Iqsdaq ★☆★PLEASE SHARE THIS VIDEO!! ★☆★Twitter: https://twitter.com/JudgeOfTheKings ★☆★Instagram: https://instagram.com/judgeofthekings/ Thank you so much for 1000 subscribers. If you like what you see, please share these… 2016-10-10T03:54:02.000Z

At both the first and second presidential debates, Trump exhibited an odd and frequently repeated sniffing behavior. After the first debate, former Vermont governor and 2004 Democratic presidential candidate Howard Dean suggested an explanation for Trump’s repeated nasal sniffling.

“Notice Trump sniffing all the time,” Dean wrote on his Twitter feed. “Coke user?”

Dean had no evidence that Trump actually used cocaine, and others listed any number of possible, non-drug-related causes for the sniffing behavior, ranging from an allergy attack to a nervous tic on Trump’s part.

After the second debate, however, when Trump’s deep sniffs continued — as shown in the video above — Star Wars actress Carrie Fisher, who has spoken and written widely of her long battle with substance abuse, again declared that Trump’s sniffing was the result of cocaine use.

@reimamy I'm an expert & ABSOLUTELY — Carrie Fisher (@carrieffisher) October 10, 2016

“I’m an expert and ABSOLUTELY,” Fisher wrote on her Twitter feed, in response to a question about whether Trump’s sniffles resulted from cocaine use.