The late Soundgarden and Audioslave frontman hanged himself in his hotel room in Detroit, Michigan, last month, and according to his toxicology report - which was obtained by TMZ.com - the star had taken a number of prescription drugs prior to his suicide.
The publication reports Chris - who was 52 when he took his own life - had Naloxone, sedative drug Butalbital, Lorazepam, decongestant Pseudoephedrine, and barbiturates in his system at the time of death.
Since the release of the report, Chris' widow Vicky Karayiannis has said the news comes as a shock after "many years of sobriety" for the star, and she is "heartbroken and devastated" by the news.
In a statement, Vicky - who had 12-year-old daughter Toni and 11-year-old son Christopher with the 'Black Hole Sun' hitmaker - said: "Many of us who know Chris well, noticed that he wasn't himself during his final hours and that something was very off. We have learned from this report that several substances were found in his system. After so many years of sobriety, this moment of terrible judgement seems to have completely impaired and altered his state of mind. Something clearly went terribly wrong and my children and I are heartbroken and are devastated that this moment can never be taken back.
"We very much appreciate all of the love we have received during this extremely difficult time and are dedicated to helping others in preventing this type of tragedy."
Meanwhile, Chris' longtime manager and close pal Ron Laffitte, said the star was in high spirits before the tragedy and insists there were "no warning signs" that he was suicidal.
He said: "Nobody saw this coming, his band mates didn't see this coming. It's totally out of character for the Chris that I've known and worked with for the last 10 years. It's incredibly bizarre. I have to think that something threw him off the tracks ... he must have been out of his right mind."
At the time, Ron speculated that drugs could have played a part in Chris' death.
He added: "Very often times people who are in recovery have a relapse or a slip. I think unfortunately what so often happens when a recovering addict has a slip is they return to a level where they left off as opposed to easing their way back in."This article was first published on BANG Showbiz and is republished here with permission.
Where to get help
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
If it is an emergency and you feel like you or someone else is at risk, call 111.