A mother-of-three from Hindley Green died sitting cross-legged on the floor at her friend's home, after taking a "cocktail" of diazepam, alcohol, and the heroin substitute methadone.
Maxine McCullough, 26, had been diagnosed one month earlier with borderline personality disorder, and had a long history of abusing prescription drugs and of alcoholism.
In the months leading up to her death in January this year, Ms McCullough was severely depressed, and had deliberately overdosed on her prescription medication several times, taking it while drinking.
She died on the sixth anniversary of her own mother's death from alcoholism.
After an inquest into her death at Bolton, deputy coroner Alan Walsh said he did not believe Ms McCullough intended to take her own life, but that she was reckless and did not understand the consequences of the drugs acting together.
He recorded a verdict of death by misadventure.
Ms McCullough , who was born with the surname Melling, was unemployed and drifted between living at her aunt's house on Atherton Road in Hindley Green and the nearby homes of two friends, Richard Bromley and Louise Ferguson.
Her daughter and two sons had been taken into foster care because of Ms McCullough 's alcoholism and psychiatric problems.
Richard Bromley said on the night she died he was with Ms McCullough and Ms Ferguson, at Ms Ferguson's house on Swan Lane. He said: "Maxine was different when she drank – like Jekyll and Hyde."
The next morning Ms Ferguson found Ms McCullough cold to the touch, sitting cross-legged on the floor. Ms Ferguson's prescription methadone container was empty next to her.
Toxicology reports found traces of methodone, diazepam and cocaine in her body, as well as large amounts of alcohol. Wigan Infirmary pathologist Dr Steven Mills said the cause of death was a combination of the effects of all the drugs.
Mr Walsh said he was satisfied that Ms McCullough had not intended to kill herself, but had not realised the consequences of her actions.
He added: "People need to know these drugs together are a massive risk. Ms McCullough might well have recovered through rehabilitation, but instead she chose to discharge herself."