Just off the county highway in Goshen, Indiana, there is a cluster of modular homes built from a kit. It couldn't be called a neighbourhood; it's just a paved road lined with identical homes set several feet apart. It is early evening in late November and loneliness pervades in spite of Christmas lights that blink in the windows. A mud-splashed Camaro, the emblem of middle-class teenage testosterone, is parked in the drive of one of the homes. The front door is unlocked. Inside, the stench of staleness is overpowering. All the curtains are drawn and the sitting room is completely dark. A giant 52in flat-screen television dominates the room and glows with a muted sitcom that nobody is watching. There are three pieces of leather furniture on which three men have passed out, fully clothed, in a deep sleep. It is 6pm. The kitchen is brand new, shiny, unused. The ashtrays are full of smoked butts and nobody stirs at the appearance of a stranger. There is no sound, no urgency, no sense of time. This is where Gerald Yutzy lives in limbo.

Gerald, 24, was raised as Amish. There is a large Amish community in Goshen and the monochrome religious world he was born into exists in a nonmechanised time warp. They live side by side with the modern (or "English") world, whose citizens greedily embrace material accessories and possessions and see no sin in using a dishwasher or a computer: people like us.

There are stalls for the Amish horses and buggies in the parking lot of the local Wal-Mart. Dressed in plain, home-made clothes, the women in grey dresses and bonnets, the men in black felt hats, braces and beards with no moustache, they can be seen in the aisles. When an Amish man marries he grows a beard - a moustache is too reminiscent of the military - and it remains, increasing in length with each passing year. In America, the Amish are still largely romanticised as gentle and private people who carry the torch of an idealised past. They live a 19th-century existence and adhere to simple, family-oriented values. They keep to themselves, don't proselytise, and don't seek to be a part of a culture where technological progress and prosperity breed pride, power and status and lead to the breakdown of relationships.

The Amish, whose roots lie in the Anabaptist movement, fled Germany for Pennsylvania in the 18th century. They do not own cars, have electricity or telephones in the home. They are polite to the "English" but inaccessible and unapproachable; they don't take photographs and frown on others photographing them.

They believe their children should only go to school until the eighth grade (age 14) to avoid becoming "too proud". Their faith centres on humility and is reinforced by church, family, community and a simple lifestyle based on farming and woodwork. It is from this way of life that Gerald has ostracised himself.

Each church district decides what it will and won't accept; there is no single governing figure. Church is held in the home. The old-order Amish are more orthodox than the new order, where activities such as using a tractor are permitted. But no matter what the district or order of Amish, there is an unwavering principle that parents do not force their faith on their children. Anabaptists believe that baptism should be a voluntary decision made as an adult, and because of this, many Amish communities practise a tradition known as rumspringa (Pennsylvania Dutch for "running around").

When Gerald turned 16 he was, like every other Amish boy or girl, encouraged to explore the "English" world before deciding whether or not to "join church". It is expected that this will help them to make an informed decision. During this time they can experience the freedoms of the modern world - dating, parties, drinking, driving, wearing jeans - and it usually lasts for a few years. Some remain at home but many choose to flee the intense supervision of their parents and rent a place of their own. Parents do not always approve of the decisions their offspring make - especially when it comes to purchasing cars and moving out - but they tolerate them. Gerald's new life is a testament to his independence, but he is able to return home any time he wishes. And when or if he is finally baptised, all sins will be automatically cleansed and forgiven.

Most return after five years, usually when they are ready to start a family. For Gerald it has already been eight years. His reluctance to return is understandable. If he returns, joins church and is baptised, then changes his mind and relinquishes his Amish ways for that of the "English", his actions will be met with a far worse reception. The Amish practice of "shunning" - a harsh expulsion - is the price he would pay. His family's door would be closed for ever.

The rate of return is high. About 90% reject the modern world and all its inducements. But a small number, like Gerald, are unwilling to give up their new-found freedom. So just how well equipped are the young Amish to handle the journey into a world they have neither the knowledge nor social skills to navigate?

They begin this journey solvent, having worked since the age of 14 and built up huge savings, but with a limited education. From a young life consisting almost entirely of chores, early bedtimes and Bible readings, cocooned by rigid family rules, crossing the street into a world of sex, drugs and gangsta rap can induce enormous stress. Is it really surprising that so many flee the scary, empty world of the "English" for the sanctuary of their Amish family?

Gerald, now awake in his house on the lonely street off the highway with the Camaro parked in the drive, is one of the estimated 10% who are neither baptised nor shunned.

"I haven't renounced being Amish," he says softly. "I just don't do it." He sits at a round dining table, a large crack across it and a triangular section of glass missing. He had been asleep in the bedroom and has emerged fresh from a 45-minute shower smelling of shampoo and wearing a hooded sweatshirt and baggy jeans.

He is still pressured by his parents to return but, since he's not spending a great deal of time at home any more, it's not something he considers a priority. His life now is about working and sleeping in his tiny bedroom, which is like a cave. It reveals a velvet Tupac poster, naked girls on the computer screen, and clothes, a remote control and some marijuana on the bed. The rest of the room is filled with an expensive entertainment system. The bedroom next to his belongs to his friend Jonas, and it has a manic spotlessness. Later, Jonas will say his girlfriend cleans it.

Jonas has woken up now and chills out watching TV. He has six sisters and two brothers and works at a factory that makes recreational vehicles (RVs). He doesn't go to church and won't give up his car because he likes the speed. He is 23 and says he knew at 17 he wouldn't go back. He was up at 6am this morning to go hunting.

Gerald isn't a hunter. He is placid, sensitive and appears reckless in a quiet way. All week he works on RVs with his Amish father at the factory, 4.30am to noon, and the rest of the day he sleeps. He speaks thoughtfully. Unlike most Amish children, who attend a one-room schoolhouse, Gerald went to a regular school but still only until he was 14. He also grew up in a comparatively small family, with only one brother and two sisters - most Amish families have 11 or 12 children. He has a mobile phone and it rings several times. "It's my dad," he says and ignores it, explaining they've had a big argument about him smoking marijuana.

There was not one particular moment when he stopped thinking of himself as Amish. It was, he recalls, a gradual thing. He doesn't think about it any more and asserts, quite a few times and with conviction, that he doesn't miss it at all. Yet he says he still believes in God and in heaven and that the easiest way to get into it is to be Amish.

Last year he wanted to see The Passion of the Christ but couldn't bring himself to watch it because he would have felt too guilty. He has the freedom to do and think as he pleases, but that thinking is still shaped by the piety of his upbringing. This confusion is manifested when he talks about a recent experience in which one of his friends was killed during a robbery.

"When I was younger I'd never have thought anyone would be capable of doing that. There is no sense in that," he says. Amish children are taught to trust and believe in the good in people. When bad things happen within the Amish community itself - mental illness, drug abuse or incest, allegations of which were recently publicised - their approach is to keep it quiet, protect their own and deal with it themselves. It is also rooted in the Amish notion of Gelassenheit, or submission. Wives obey husbands, children obey parents, and the Amish believe it is sinful to withhold forgiveness. Understanding something such as a random act of violence is difficult for Gerald, because of his cloistered upbringing. He sighs. "After a while, you get to a point where it doesn't surprise you. Sometimes I don't believe that good things happen to people any more."

It's hard to tell if his cynicism is the result of living in the "English" world or if it's part of the natural, organic process of growing up. He admits he was never cynical before.

A few hours have passed and Gerald has agreed to dinner. Going out to eat is not something he and his friends do often. There aren't many options other than fast food, and there are days when he will forget to eat. There is also not a lot to do in Goshen. There is a pool hall in town and there are movies and a bowling alley, but most nights he and Jonas stay at home.

Jonas refuses to move from his chair. He promises he'll come out the following night but Gerald is sure it won't happen and he is right.

Gerald's manner is low-key, so when he reacts with a jolt of emotion, it registers. We are seated now in a booth in a faux Italian restaurant, and he sips a beer and picks at the "never-ending" salad. He is surprised to hear that 90% choose to return and join church. "Ninety?" His eyes roll. "It's much higher than that. I'd say it's 99.9."

Apathy and torpor imprison him; it might be the marijuana or it might be the deadening boredom of small-town America, or it might be that his childhood never prepared him to think about independence, ambition and a life outside his family and church. Now he occupies the space between those two worlds, a holding pattern of drifting and sleeping.

"Nothing excites me. I'm a goal-less person right now. And that's the thing. I need to have some goals and get on track. I have no ambitions: I just go to work, come home, go to work and sleep." He takes a sip of beer. "I know I can't live like this for ever." He talks about a desire to travel, but the interest is distant. He went to Florida and saw the ocean. He's been to New York. Both were "all right". "Sometimes it's better just to stay at home. You know what I mean?"

And what about his parents? They find it hard to accept the choice he seems to have made. They want him to return, they want a reason why he doesn't. But he doesn't have one. For Gerald, and for many young Amish, their way of life is less about religion and more about lifestyle. So when I ask what is better about his new life, he makes an important distinction: "It ain't better. But I like it."

Yet he believes that the freedom he has is not good and, curiously, despite the things it brings him, he considers himself disadvantaged. The recognition that the life he rejected is the advantaged life is surprising. "Being Amish, you are connected to a community. They will do anything to help you. Everybody chips in." He shrugs at his current decision to reject it. "I don't get it myself," he confesses.

Perhaps part of it is that Gerald is a solitary person and hates "contracts" of any kind, be they religious or otherwise. Personal freedom means he can be left alone. He had a serious girlfriend but she betrayed him (he won't talk about this), and since then he's not been very interested in dating. He could if he wanted to - though he doesn't notice the girls who glance at him as he walks by - but he admits he has no libido right now and doesn't see himself getting married.

A few years ago he was asked to be on Oprah, but backed out at the last minute because he felt weird. Then when he saw the show, he was disgusted because he believed she portrayed the Amish as stone-age dwellers and Amish women as breeders. When he talks about this, it's clear he still feels loyal, protective and defensive about his former community. Does he doubt his current decision to leave the church? He shakes his head. "I know I haven't made a mistake, I know I wouldn't be happier being Amish because I don't like being Amish, but at the same time it would be so much easier and better for me."

There are billboards lining the highways around Goshen showing emaciated torsos. The caption reads "Body by: Crystal Meth".

Methamphetamine (more commonly known as speed) is a popular drug in this part of the country and one of its most insidious characteristics is that it gradually destroys the part of the brain that governs the experience of pleasure. The emotional memory and the ability to recall enjoyment are damaged. This also makes it harder to enjoy life once one gets sober. Speed is considered the most addictive drug because it boosts the brain's production of dopamine, flooding it yet inexorably strangling its wellspring until the brain no longer produces enough to maintain a healthy emotional existence. It lessens the brain's ability to re-create pleasure, and that's why relapse is so frequent - recidivists take it to get back to a feeling of euphoria that no longer exists.

It's hard not to surmise, harder still not to speculate, that the lethargy, the uncharacteristic lack of hormone-fuelled excitement, ambition, or just plain get-up-and-go in Gerald's circle of young friends may be something to do with the drug culture of this small community. The spotless room (obsessive cleaning and tidying are sometimes a result of the speed-fuelled rush), the excessive sleeping, the staleness of their existence, are powerful circumstantial indicators.

Smoking methamphetamine results in an instant dose of the drug reaching the brain; the rush is followed by an ability to stay up for up to 36 hours at a time. Factory workers get paid by the piece, so the longer they can stay up, the more money they can make. Crank - the chalky form of methamphetamine - is more accessible than crystal meth (otherwise known as ice), and ingredients can be bought at a grocery store. It is easily made. An addictions-treatment provider at the local recovery centre says: "Anyone with an eighth-grade education can make it."

"Most of the people who are referred here are referred by the courts. There are not a whole lot that come who are intrinsically motivated." He guesses 8% to 10% are Amish and, given the rigorous custodial nature of Amish life, they must mostly be on their rumspringa break, since the Amish community itself provides local law enforcement with few problems. It is also not uncommon for the Amish who do become addicted to drugs to return and join church as a form of rehab and recovery. Julie Dijkstra, the chief deputy sheriff of Elkhart County, says that the Amish deal with problems internally.

She says they are so closely supervised that there is not much that is reported.

Lyndale Schmucker leans against his red truck, which is parked outside Gerald and Jonas's house. He is punching numbers into his mobile phone. It is the next night and Gerald is inside, asleep in his bedroom, and the front door is locked. Lyndale is waiting for Jonas, who hasn't come back yet. Lyndale's rejection of the Amish world is deeper, more aggressive than Gerald's, and he feels no loyalty to his roots. He digs his hands deep into the pockets of his jeans and looks down at the ground. His voice is low and, as he talks about not considering himself Amish at all any more, an increasing animosity creeps in. For him, the rejection is a reaction to hypocrisy. He still goes to church and tells of the time he wore khakis instead of Amish clothes. "I'm like, they're plain, they're dress clothes. But they didn't like it. I'm just like, why do you look at a person's clothes? We're all there for the same reason. Are we there for our clothes? I don't understand." He cites a long list of inconsistencies. For instance, the Amish won't allow a telephone in the house, but they'll use a public phone.

"I just can't see why Amish people don't allow a phone. You need a phone. Phones can save lives. They can have one outside - five feet away - but not in the house? And they don't want us to have vehicles because it's wrong - but then they want us to take them everywhere.

"I told my mom I'm not joining church until you can tell me what's the difference between a phone in the house and one five feet outside the front door. She's like, "Well, you won't use it as often as you would if it were hanging on the wall.' But as soon as you need a phone, you're gonna go out and use it." Lyndale is like one of the sturdier characters in Beavis and Butt-Head. Nearly every sentence ends with a shrug and an "I don't know. That's just me". His mother thinks he'd be happier if he joined church, but he's far from convinced. "If I sold my truck and everything I've got, how could I be happier?"

He acknowledges that being Amish is less complicated for one reason: "You don't spend money." But, at 23, how can he be sure he'll never be Amish again? His reason is, it doesn't make sense. When asked about the transition, he admits it wasn't easy: "You go through a lot. You have to fight. Going to buy your first truck - your parents don't want you to do it. They're crying because it's wrong. They hold out hope. It's hard for them to see their kids not obeying.

"Amish just makes your life harder. You always have to bother someone to take you somewhere - or you have to ride your bike somewhere to make a phone call if it's not in your yard. If I want to go somewhere, I just jump in my truck and I go." He looks off into the distance. "I can't see giving up my truck, my phone, go to nothing."

It seems, for the most part, those who choose not to return are torn but not confused.

They are not considering the psychological impact or the spiritual consequences of their actions because they are not ruminating about the choice between the Amish world and the "English" world. They are simply asking themselves the question that occupies any young mind: "What will make me happier?" And they are not convinced Amish is the answer. There's certainty and security versus adventure and adversity - the known versus the unknown - or even God or no God. And for the Amish who do not return and join church, it is often less of a decisive action or a statement of belief than a realisation that they just don't want what they had before. What they are giving up is a lifestyle more than a religion. And owning a car is a lot more appealing than a horse and buggy.

North of Goshen, Mary Mosley is waiting at the McDonald's off the interstate. It is not just boys who reject the Amish world. The girls do too, and for greater apparent reason. Women are still very much subordinate to the men. Mary made the brave decision to leave the Amish world and now lives completely shunned. She has agreed to meet for coffee and is sitting with both hands folded neatly in front of her resting on the table top in front of a plastic tray with a box of fries. Her voice is barely above a whisper, but she is eager to talk and several hours go by as she tells her story.

Mary was raised as Amish in Nappanee County and began working at the age of 18 making aeroplane-seat covers. She still wore Amish dress, but knew she wouldn't join church. She says she knew this around 15, when she was old enough to realise that "they say these are the rules but they don't follow them".

It's true that it doesn't make sense. The Amish won't own a car, but they will gladly ride in one. The Amish point of view is that only the wealthy can afford to own a car, therefore it creates inequality and separates the community. It displays wealth and status, and is a divisive tool. But Mary is unimpressed. She found hostility and snobbery among the Amish, and believes that inequality isn't eradicated by banning car ownership. In her case, the sense of inequality came because her family was poor. "There is no community for poor people."

Growing up, she was ridiculed for the material her dresses were made from. "If you didn't buy certain fabric, you weren't in." It was difficult for her family. For instance, while the Amish do not allow ownership of motorised vehicles, a four-horse buggy denotes more wealth than a single horse. And the breed of horse too. "There's huge competition with the horses. Whose is stronger and all that. And why is it okay for a boy to get a car but not a girl?" she asks. Tugging at this question was one of the many threads that unravelled her faith. The expectations of Amish women are non-negotiable. They won't work once they have children. They do not have equality with their husband. Mary was unsure about this early on.

But there were other contradictions too.

She explains how some women are allowed to have mobile phones when they are pregnant and to keep them in the house long after the birth. And some of the new-order Amish will allow electrical appliances in the house (like a blender) or keep power tools in the garage. She believes that in spite of the dictum for equality, there is just as much competition in the Amish world as there is outside it - they just don't talk about it.

She lived at home until she was 21, becoming increasingly disillusioned. "I'd see the Amish name used in advertisements for bread and peanut butter." But she was raised to believe that if she weren't Amish she wouldn't get into heaven. She moved out, shared an apartment with a girlfriend who was Amish, and worked as an electrician. Her family prayed she'd come back. She did, and the slate was wiped clean. But shortly after the baptism she felt she was living a lie. She didn't feel comfortable and, more disturbing to her, she was discouraged from thinking for herself.

Once she decided she was no longer going to be Amish, she felt at peace. She stopped dressing in Amish clothes and felt liberated. She lives with her "English" husband and his son and stepdaughter now, and feels partnership far more than she could expect from an Amish man. "He respects me more, we do everything together. I don't think I'm stupid to want this."

She no longer feels included in the family but she says there is not much about being Amish that she misses. "I miss driving the horse and the buggy on a cold winter morning and hearing the wheels crunch in the snow. It was peaceful."

But that is just a momentary glimpse of nostalgia. At 29, she has made a courageous change, which gives her pride and comfort. She looks out of the window over the parking lot and slides the tray of untouched fries away. "Simplicity can be had anywhere."