It was turning out to be the best holiday ever - shopping on Fifth Avenue, ice-skating in Central Park. Publishing executive Emma was on top of the world as she hammered her credit card and chatted incessantly to New York taxi drivers and anyone else who'd listen. "I was on such a high" says Emma, 27, recalling her week in the Big Apple. "Everything was perfect. I felt unstoppable, as if nothing or nobody could hold me back". Even an explosive argument with her best friend Rachel, who'd accompanied her on the trip, didn't spoil things. "I've always hated confrontation and never lost my temper", says Emma. "But suddenly, when Rachel accused me of flirting with a guy in a club, I went ballistic. "This huge rage was rising up inside me and we had a big row. But I was in control, telling Rachel exactly why I was so upset. It was amazing to be able to express my anger so eloquently and I shocked myself as well as Rachel. I felt powerful and liberated".

These strong feelings, however, weren't caused by the euphoria of being in New York. They were symptoms of a devastating illness which led Emma to contemplate suicide after being drugged and locked away in a psychiatric hospital. Unbeknown to her, Emma had Bipolar - better known as Manic Depression - which has changed her life forever.

During a "manic" episode she could get by on just two hours sleep a night and had boundless energy. It may sound great but the next stage was psychosis, when Emma suffered from delusions and paranioa during prolonged periods of clinical depression. "I never imagined I'd ever had a mental illness," says Emma, "I had the stereotype in my head of a drooling tramp or that schizophrenic who climbed into the lions' enclosure at London Zoo. But I'm a middle-class career girl with a steady boyfriend and lots of friends. Now I look at the whole issue of mental health differently. If it can affect someone like me, it could affect anyonbe". Thankfully Emma's symptoms have been controlled by drugs which stabalise her mood. But she and her doctors have to be alert in case she slips back into her mania. "I have to 'manage' this illness for the rest of my life, obviously at 27, I could have done without it, but I'm a strong believer in the saying : 'What doesn't kill us makes us stronger'. The experience has made me a lot more compassionate and non-judgemental. Words, such as crazy and nutty are just labels. People casually use the expression "manic" when they mean they feel harassed or frazzled. But it's a serious condition". Emma's manic depression struck her without warning but, with the benefit of hindsight, she believes she acted out of character almost as soon as she got on the flight to New York. "I hate flying and practically had to be dragged onto the plane, but I was fine after a few drinks. In the end, I was joking with the air hostess like they were old friends". But while she is naturally outgoing, Emma just kept on talking and talking. "My mood just got better and by the end of the week, I was ecstatic. I lost all my inhibitions, I now know that manic depressives become sexually uninhibited and, to be honest, I was very flirtatious and tactile. I've been going out with my boyfriend for four years and there's no way I would have been unfaithful. But I 'was' enjoying all the attention."

The morning after her argument with Rachel, Emma visited the Ground Zero, the site of the September 11 attacks. "It would have been an emotional moment for anyone, but somehow it affected me terribly. I was reading a poem which had been pinned to a wall. It was very simple, I felt a wave of sadness like nothing I have ever felt. I couldn't stop crying, but it wasn't like normal crying. My whole body was racked with sobs. Like the row with Rachel, it was cathartic. It felt like a massive release of energy". When she finally stopped crying, she went on a spending spree. "The previous night, I'd given away all the dollars I'd brought with me to a beggar, but even though I'd used up my credit card limit, I spent more than £600 in a couple of hours". Among other things she bought three jumpers, three pairs of trainers and a patchwork suede coat, which she now refers to as her "manic depressive coat". "When my psychologist saw it, she said it was the sort which manic depressives often buy - it's loud and conspicuous so it appeals to their personality".

Back in the UK, she says she was "ultra aware" of everything - tastes, smells and sensations. " I bought a watermelon - my favourite food - and it was the best I'd ever tasted. And when I saw my boyfriend again, we had the most amazing sex. I'd only be able to sleep for two or three hours a night. My mind was racing and I'd sit in the bathroom writing stories and poetry. For the first time in ages, I felt creative and inspired". Emma had booked another week's holiday and spent her time shopping and contacting old friends. "I got talking to everyone, neighbours, shopkeepers, you name it, I was on such a high". But then the euphoria turned to psychosis. Watching an episode of Star Trek, she was convinced the characters were talking to her. "I also started talking about myself in the third person and then I began thinking I was God. When we were lying in bed, I'd sit bolt upright and shout out the name of the disease I thought I had. One minute I screamed out Aids, the next it was meningitis. My boyfriend was beside himself and didn't know what to do".

The next morning, he telephoned Emma's mother, who insisted he brought her to her home. "The people on the train must have though I was mad, I kept quoting passages from the Bible because I still thought I was God. For some reason, I got it into my head that we were travelling to Devon to die". Emma's family met them at the station, "I imagined they were the Devil's congress who wanted to kill or harm me, they were sitting eating Burger Kings on the sofa and I felt I was the Last Supper". Delirious she tried to communicate in sign language. When Emma's distraught mother told her to stop behaving so strangely, her daughter collapsed and had a fit. Her eyes rolled back and she fell and cut her head. An ambulance was called and she was taken to hospital, where she tried to bite her stepfather and run naked through the casualty ward. It was there that Emma was sectioned under Section 5 (2) of the Mental Health Act. It meant she temporarily lost some of her rights and that drugs could be administered without her permission. She was told she could be a danger to herself and others and the sectioning had been done for her own safety. "I vaguely remember someone reading me my rights, but that's about it", says Emma, who was taken to the psychiatric wing. There she was heavily sedated and placed in a room monitored by CCTV cameras. "I had the shakes and behaved like a drooling zombie", says Emma, who wasn't allowed to see her family froa week - although they could watch her on the monitors. "The only place I could sleep was on a bean-bag in the middle of the room. The bed was covered in a plastic sheet and I couldn't bear to lie on it. I kept flicking the light switch on and off as a signal to people to come and rescue me" The psychosis was controlled by drugs, but Emma's conditions wasn't properly diagnosed for more than three months.

Meanwhile, she became severely depressed and was unable to to simple tasks. "I was there for three-and-a-half weeks and then, after a spell at home, I went back to work. It was a nightmare because I'd lost my confidence. Before, if my boss asked me to do something, there was no problem. But now I was anxious about everything". Her boss was one of the few people who knew the gravity of the problem, but other colleagues commented on how withdrawn she'd become. "At that stage, I didn't even think I was mad or crazy, I didn't even properly recognise the fact I was depressed. Instead I blamed my anxiety on stress" She would wake up at 5am, terrified of the day head and be unable to get back to sleep. She lost her appetite and her weight dropped dramatically. "I lost touch with my friends and would site at home all night chain smoking" It was during that period that her boyfriend asked Emma to marry him, promising her they would face her illness together. "That meant so much and I accepted straight away, I was amazed that he'd put up with me. But, even so, I was scared that he'd leave me for someone who was more straightforward and happy".

Later, Emma was seen my a consultant psychiatrist at the Priory Hospital. Her firm had private health insurance with BUPA and she was admitted immediately. The consultant diagnosed Bipolar and eventually put Emma on experimental doses of drugs, including anti-depressants and mood stabalisers. "For the first eight or nine days, I was in the depths of depression, I was on suicide watch, the nurses would check on me every 10 minutes and I would fantasise about the different way I could hang myself and where I could buy a rope. But I doub't I would have had the guts to go through with it. My boyfriend and my mum came to visit but I'd often be in a catatonic state. I'd lie on my bed, expressionless, unable to get dressed or even brush my teeth." At the Priory Emma mixed with patients suffering depression, post-traumatic stress, obsessive compulsive disorders and others who self-harmed. "There was a range of people - from housewives to bankers, media types to college students - it made me realise how widespread mental illness is." As her mood lifted, Emma attended group therapy sessions and studied Cognitive Behavioural Therapy, a method of thinking more positively and creatively. "It's a myth that the Priory is more like a stars' health farm than a hospital." says Emma. "It was nice to have a private bathroom and the setting is pretty, but when you're ill, all you want it for the therapy to work".

Despite a few setbacks, Emma became more stable and was eventually discharged after six weeks. She returned to work part-time and now has a shorter working day, between 9am and 4pm. She will probably have to take the prescribed drugs for the rest of her life. "I feel 100% back to normal and my work hasn't been affected, but we still don't know why I developed this illness" There is no history of depression on her mother's side of the family but she has never know her father. Most experts believe stress and genetics are the most common cause of Bipolar, which can be exacerbated by a variety of experiences and emotions. "I'm constantly searching for reasons, but I'll probably never know. I can minimise the risks by exercising regularly, eating heathily, drinking less and getting eight hours sleep a night. It's a small price to pay for peace of mind. I feel normal again now, like I did before I was ill and possible more calm. Things don't stress me out so much. When you've been to such an extreme, it puts things into perspective." She goes to monthly meetings of the Manic Depression Fellowship, where sufferes can share their experiences. "My illness had changed my life, but not necessarily for the worse".