You Lost Me is the title of a 2011 book by David Kinnaman, who runs a large market research company in North America. In it, he describes the widespread phenomenon of young people disconnecting from churches, and explores the reasons for their departure.

Comedian Katy Brand is pretty clear why she left the Buckinghamshire church she so strongly identified with from the age of 13. In I Was A Teenage Christian, she talks about her gradual disillusionment with leaders who banned Harry Potter, and who flatly disapproved of her choosing to take a degree in theology.

Hostility to debate is a clear problem identified in Kinnaman’s research among churches – particularly in the area of science. In Britain and America alike, there is often little choice for a young person faced with an apparent conflict between a fundamentalist, literal interpretation of the creation story, and the evolutionary science they need to pass their exams.

Yet in the early days of her church-going, Katy Brand reports feeling a delight that she was part of something that seemed important – delighted enough that she would attend church three or four times a week. She has said in interviews that she can see how fundamentalism can seem attractive and "exactly why" young people are being radicalised at the moment.

To understand why some do become radicalised is proving controversial for the UK government, however. Criticisms of a parliamentary report included a failure to define terms like radical and extreme, or to recognise the complex social factors that might cause anyone – not just Muslims – to radicalise.

But research with people of Pakistani and Bangladeshi origin living in the UK has revealed a mental health perspective to the debate. In his work with 600 people in Muslim communities, Professor Kamaldeep Bhui of at Queen Mary University of London found a positive correlation between extremist sympathies and being young, in full-time education, relative social isolation, and having a tendency towards depressive symptoms.

While radicalisation doubtless has many causes, this is important information for all looking to understand young people grappling with a sense that they are lost.

- Rebecca Mileham

I Was A Teenage Christian ran at Pleasance Courtyard until August 26th - https://tickets.edfringe.com/whats-on/katy-brand-i-was-a-teenage-christian-2

David Kinnaman’s research company: https://www.barna.com/research/

Interview with Katy Brand: https://www.theguardian.com/stage/2016/jul/04/katy-brand-teenage-christian-comedy-interview

Home Affairs Select Committee report into Radicalisation: http://www.publications.parliament.uk/pa/cm201617/cmselect/cmhaff/135/13509.htm

Mental health aspect to radicalisation: https://www.newscientist.com/article/mg22630160-200-radicalisation-a-mental-health-issue-not-a-religious-one/

Depression a factor in radicalisation: http://www.telegraph.co.uk/news/uknews/terrorism-in-the-uk/11164182/British-jihadis-are-depressed-lonely-and-need-help-says-Prof.html

The setting for Torch is a narrow one: its narrator has locked herself in a toilet cubicle at a nightclub, unable to summon the confidence to storm the dancefloor despite plenty of shots and a snort of coke. Within its confines, she journeys across her past, reflecting on the relationships and sexual experiences that shaped and eroded her sense of self. It's a history of disappointment, mostly: whatever she wanted of the men who paraded through her life, she never got it. All that remains of them is a set of lifeless mementoes, a jumper maybe, recording their interaction.

But the disappointment is also in herself: reaching back to her teenage years, she wonders at her youthful exuberance, revels in the memory of her ease in her own body. Having sex for the first time, she says, “I finally understood my own power.” That teenager didn't hide her body behind baggy t-shirts, and didn't need a man's permission to do anything. More than once the woman cries out that she wants that teenage self back.

The experiences described in Phoebe Eclair-Powell's text are common enough to feel like archetypes; performed by Jess Mabel Jones, iridescent with gold glitter strewn across her eyes and lips, they gain a potent charge. Interspersed between each anecdote is the song this woman might have belted out in her kitchen, or listened to on an iPod while crying on the nightbus: some morose, some cheeky, none of them specifically relevant to the story but useful all the same. There's some fascinating neuroscience describing the ways in which music – especially the music heard as a teenager – impacts on the human brain: the nostalgia connectors that develop as a result are the same ones triggered by this show.

The text doesn't do much sexual-politics work: the affairs described are all heteronormative; and although the woman remembers with regret not kissing a woman she found attractive, her desire for lesbian experience is vague. And although the work is feminist on the surface, it's noticeable that the woman seeks self-definition in sexual relationships rather than intellect, work or non-physical engagement with the world. In essence, Torch is itself a torch song: a shot of emotion directed straight at the heart. (MC)

Torch is on at 20.50 at Underbelly Cowgate until August 28th. Hearing Loop - https://tickets.edfringe.com/whats-on/torch

On the lack of scientific research into female sexuality: http://www.slate.com/blogs/outward/2015/08/03/sexual_orientation_in_women_why_so_little_scientific_research.html

On lesbianism and sexual fluidity: https://www.theguardian.com/lifeandstyle/2013/nov/26/lesbianism-women-sexual-fluidity-same-sex-experiences

Questions raised by women equating sex with power: http://everydayfeminism.com/2015/12/power-in-sexuality-problem/

The neuroscience of musical nostalgia: http://www.slate.com/articles/health_and_science/science/2014/08/musical_nostalgia_the_psychology_and_neuroscience_for_song_preference_and.html

On the benefits of nostalgia: http://www.nytimes.com/2013/07/09/science/what-is-nostalgia-good-for-quite-a-bit-research-shows.html?ref=science&_r=1