An inquest in York heard that 19-year-old Toni Haw died after an overdose of medicine and alcohol that was graphically referenced in the “very disturbing” and “irresponsible” publication.
Her boyfriend, Alan Hutchinson, 30, killed himself by taking the same medication less than a month after her funeral as he struggled to come to terms with her death.
The Coroner for York, David Coverdale, branded the book, which is published independently, as “wicked” as he claimed it encouraged people at a low ebb to consider taking their own lives.
The book, which the Yorkshire Post has not named at the request of The Samaritans, claims to be intended for “rational suicide” in the face of “unbearable and unrelievable suffering”, specifically for patients with terminal illnesses.
But Mr Coverdale said: “It seems to me that it can act as a clear encouragement for people who may be at a low ebb actually to end it all and take their lives. It is a very, very disturbing book and I am deeply shocked that it is possible to acquire a book like this.
“It has to be said that if Toni Haw had not had access to this publication she may not have taken the overdose which ended her life.”
The coroner said the book was explicit in its descriptions of various suicide methods and the one which led to Miss Haw’s death was mentioned specifically and graphically in it.
Her mother, Hilary, 51, said: “I think this book did have a significant effect on my daughter’s actions and am shocked that these kinds of publications can be so easily obtained.”
The inquest heard Miss Haw, from York, who had been taking a course to learn sign language, had a history of stress and social anxiety, had been prescribed anti-depressant medication and had taken overdoses in the recent past.
Her mother checked on her daughter before bed and noticed her speech was slurred, then found several empty and half-empty packets of pills and an empty bottle of spirits.
She called an ambulance to take her to hospital but Miss Haw died in the early hours of February 28.
Mr Coverdale recorded an open verdict, as he said he could not be sure Miss Haw intended to end her life.
Her boyfriend, a kitchen porter, was found at his home on March 23 with a note which emphasised the distress he had suffered since her death. A copy of the order of service from her funeral and a picture of her were found with his body.
It was surrounded by bottles of wine and vodka and cans of lager. Tests showed an excess of the medication in his body.
Recording a verdict of suicide, Mr Coverdale said: “He was aware of the means by which Miss Haw ended her life and he had chosen to take the same substance to excess to end his life.”
Chris Docker, director of Exit, an organisation founded to provide information to people on how to end their lives, spoke on behalf of the author after the hearings.
He said: “People can be irrationally overcome at any age and I think all we can do is slow them down a bit, have them take a deep breath and think about it.
“I don’t think the book precipitates someone’s suicide or not having the book prevents someone’s suicide, and some letters we have had say it gives people the courage to live longer.”