Jodie Simpson, 38, fell into a vegetative state after taking an overdose of drugs at her home in Barrow, Cumbria, in 2012.
She died in June after her family fought for a legal ruling to withhold nutrition and hydration.
The coroner ruled she died of a brain injury resulting from the overdose.
Ms Simpson's brother Michael Devlin told the inquest his sister had a history of drink and drug use and had been on a "weekend bender" before he found her collapsed at her home.
She ended up in a vegetative state with no sign of consciousness.
She was able to breathe without assistance but needed to be fed and given liquid through a stomach tube.
Her mother Jean Simpson said: "I knew from the beginning there was no hope, my worst fear was that she was actually minimally unconscious.
"No one would want to live like that."
Doctors agreed there was no chance of recovery yet the legal application to allow her to die was subjected to years of delay.
She told the inquest her family was "treated as insignificant" by the authorities and she had lost faith in professionals.
Cumbria Care Commissioning Group has since apologised for the process taking so long.
The coroner said looking back to the events of 2012, there was no evidence Jodie Simpson intended to take her own life.
A woman who spent four years trying to get permission to allow her daughter to die has told an inquest the delay was "excruciating".