Pretty much everyone suspected that Houston struggled with substance abuse issues, which she confirmed during her notorious interview with Diane Sawyer. But the true extent of her drug use wasn't clear until the toxicology report from her autopsy showed that she had been a chronic user of cocaine, according to USA Today. She was also "acutely intoxicated with cocaine" when she tragically died. 

Although the public didn't know it, Houston's loved ones had been concerned for a long time about her drug use. That includes her mother, Cissy, who once saw her daughter extremely intoxicated. "I saw her one time really high," she revealed in an interview with Oprah Winfrey. "I wanted to hurt her, I really did, because it hurt me so bad." 

Her brother and sister-in-law, Gary and Pat, were also worried, as they felt her drug use had "gone overboard" to a dangerous place. "I knew that she was in trouble," Pat confessed in an interview with Nightline. And while everyone did what they could, in the end it wasn't enough to save her.