The survey of 4,600 individuals identifying as gay, lesbian, bisexual or same-sex attracted found one-in-ten (458) had first-hand experience of the controversial practise.
Of those, almost a third (91) told the Ozanne Foundation they had attempted suicide, while more than two-thirds (193) had been affected by suicidal thoughts.
Project Leader Jayne Ozanne (pictured below), who experienced mental ill health after bids to alter her sexual orientation, said "urgent action" was needed.
She said: "For many, much of this report will confirm what they already know regarding the dangers of 'conversion therapy'.
The National Faith & Sexuality Survey was overseen by an Independent Advisory Board which includes the former President of the Royal Statistical Society, Prof Sir Bernard Silverman, who was also the main adviser on research to HMG and the @BishManchesterhttps://t.co/G9Uu9zhnj2— Ozanne Foundation (@OzanneFoundn) February 21, 2019
"However, it is the scale and severity of the problems experienced and the age at which children are said to be exposed to these practices that are of the gravest concern.
"The high level of reports of attempted suicide and suicidal thoughts amongst those who have attempted to change their sexual orientation is not something that can be easily dismissed.
"These are serious safeguarding issues which require urgent action."
More than half of respondents who said they had experience of the practice reported that their first encounter took place when they were aged 18 or under.
Two-fifths reported experience of self-harm, while a quarter said they had been affected by an eating disorder such as anorexia or bulimia.
Chair of the Foundation, Rt Revd Paul Bayes the Bishop of Liverpool (pictured below) said: "The level of considered and attempted suicide reported here is shocking and sobering.
"The statistics reflect lives which have been scarred and strained by mixed messaging of love, acceptance, condemnation and fear.
"My hope is that the courageous sharing of our respondents will not go unheard, and that human flourishing and human life will not be treated as a mere intellectual battleground for dry conversation."
A small portion of people answering the survey (22) said they had been forced into sexual activity with a person of the opposite gender - with "overwhelmingly unsuccessful" results, the report concluded.
The 'Faith and Sexuality Survey 2018' is due to be presented to the Church of England's General Synod during its meeting in central London this week.
Last summer, Premier reported on plans by the Government to outlaw gay conversion therapy.
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