The wife of Chris Cornell — the Audioslave and Soundgarden frontman who died by suicide in the early hours of Thursday at age 52 — released a statement Friday that raised questions about the nature of his death. The singer-songwriter’s wife, Vicky Cornell, said she believes that the prescription anxiety medication Ativan (also known by its generic name Lorazepam) may have played a part in his mindset leading up to his suicide.

“We discussed plans for a vacation over Memorial Day and other things we wanted to do. When we spoke after the show, I noticed he was slurring his words; he was different. When he told me he may have taken an extra Ativan or two, I contacted security and asked that they check on him,” she said.

Read: Chris Cornell Wife Vicky Karayiannis Breaks Silence On Suicide, Why It Was ‘Accidental’

Avitan is a benzodiazepine used to treat anxiety as well as seizure disorders like epilepsy. Side effects associated with the drug — which comes in strengths of 0.5 mg, 1 mg and 2 mg — include drowsiness, confusion, depression, self-harm and suicidal ideation. Ativan is also known to cause dependency in individuals with histories of alcoholism or drug abuse. As Ativan is a controlled substance, federal law prohibits the transfer of the drug to any other individual than the one to whom it is prescripted.

Kirk Pasich, a lawyer for the family, reiterated in a statement to the Associated Press that Cornell’s family believed “drugs or other substances” — including Ativan, for which Cornell had a prescription — may have contributed to the musician’s decision to end his life.

“Without the results of toxicology tests, we do not know what was going on with Chris — or if any substances contributed to his demise. Chris, a recovering addict, had a prescription for Ativan and may have taken more Ativan than recommended dosages,” he said. “The family believes that if Chris took his life, he did not know what he was doing, and that drugs or other substances may have affected his actions.”

Read: Chris Cornell Cause Of Death: Soundgarden, Audioslave Vocalist Dies At 52

Cornell had a history of substance abuse before seeking treatment for addiction in 2002. In a 1994 interview with Rolling Stone, Cornell talked about his drug problem that began before he was even a teenager.

“I went from being a daily drug user at 13 to having bad drug experiences and quitting drugs by the time I was 14 and then not having any friends until the time I was 16,” he said. “There was about two years where I was more or less agoraphobic and didn't deal with anybody, didn't talk to anybody, didn't have any friends at all. All the friends that I had were still fucked up with drugs and were people that I didn't really have anything in common with.”

Cornell hanged himself in a hotel room bathroom Wednesday night. He was reportedly found by his bodyguard Martin Kirsten in the early hours of Thursday morning after Cornell’s wife contacted Kirsten concerned that her husband wasn’t acting normal. According to reports, two doors had to be kicked in to reach Cornell, who was found lying on his bathroom floor.