Whenever I start a new job, I try to check the building for empty rooms or quiet places. As one of the 420,000 people in Britain who has epilepsy, I always like to find the places where I can cool off my brain if I feel a seizure coming on. Not that it always works. As a journalist, I have had seizures working on news desks, in editing suites and out on shoots. There is nothing more unnerving when watching film rushes than hearing a dull thud, off-camera, then realising that someone collapsed on the filming shoot and it must have been you.

Like many people, my fits started at puberty. I had my first full convulsive seizure, aged 11, in the school library. I then continued to have the occasional fit, usually during my least favourite activities - maths, chemistry and cross-country runs.

Finding out I was epileptic was a big shock for someone already dealing with all the changes of puberty. I remember thinking 'How will I ever be attractive now?' and the deep humiliation of being ejected from the local swimming club.

But my school's reaction was OK. I wasn't allowed to climb in the gym but no teachers made strange comments and I was never teased by any of the kids. I think they'd all been given a talk about epilepsy.

Meanwhile I gradually learned to deal with seizures: not eating regularly was a bad idea and not getting enough sleep would sometimes put me in danger. Forgetting to take medication was another prime source of trouble. But often I would get enough warning of a seizure to let people know that I was feeling strange.

Much still remains a mystery about epilepsy. Seizures, caused by a temporary disturbance in the electrochemical activity in the brain, can be the result of injury. As for me, several of my aunts had seizures and it helped me to know that I wasn't the only person with this condition. "Oh it runs in the family," I would say when people asked.

Throughout life, I have used a variety of drugs to control my seizures, none with complete success. And I know from experience that many can have unwanted side effects, such as weight gain, double vision or risk of liver damage.

At various times, I have tried controlling my seizures in other ways, such as meditation or homoeopathy, always using these methods in conjunction with medication. I can't claim to have found a solution yet.

It wasn't until I hit the job market after university that I first noticed other people's reactions and realised that other people's feelings about epilepsy could have a major impact on my ability to earn a living."It's not that we have a problem with your epilepsy, but we would worry about your health," said one employer as she turned me down.

At 18 I was offered one job subject to a medical. After I said that I had controlled epilepsy, I was rejected for the job on the medical grounds that, "Your teeth aren't in good condition, you need a filling." Even now, I can remember my fury and embarrassment. I knew that I had been discriminated against and, back in those days, before the disability discrimination act, there was nothing I could do about it.

There are 40 different types of seizure, ranging from brief, hardly noticeable "absences", to the more dramatic "tonic clonic" seizure, still sometimes called a "grand mal" seizure. During these people lose consciousness and convulse. My seizures tend to be these quite dramatic ones. I'll feel a bit strange, think, "Oh my god I'm in danger of having a fit," and wake up either still at my desk or on the floor.

But while 80% of people can control, or partially control their epilepsy with medication, discrimination in the job market remains difficult, and so do some people's reactions to epilepsy. There's still a lot of fear about the condition, and the old assumption that you have some sort of mental disorder or illness lives on.

Epilepsy is now covered by the disability discrimination act but "some employers still run a mile when they hear that a person has epilepsy", says Elaine Faulkner, of the National Society for Epilepsy. The NSE estimates that if the average person takes 10 interviews to get a job, someone with epilepsy will need 20.

Dr John Chaplin, chair of the International Bureau for Epilepsy's employment commission, reckons that 25% of people with controlled epilepsy are unemployed as a result of stigma about the condition.

As for me, I got my first magazine journalism job by pretending I did not have epilepsy. The editor was often out and did not realise that I occasionally used his office as my own private seizure space. I finally came clean about the seizures three years later, when I was offered the news editorship.

Nowadays I wouldn't feel comfortable working for people who didn't know about my condition. It means that I can tell them what to do if I have a fit and I don't have to play at being someone I am not. People accept that once every few months I keel over.

But for anyone with epilepsy, being in the workplace means having a range of strategies for avoiding seizures at work if at all possible and dealing with them when they happen. I know that I'm vulnerable to seizures at certain times. If possible, I don't combine lack of sleep and stress at the same time as my period. I also try to avoid spending too long on a computer without a break.

Sometimes it works, sometimes it doesn't - and sometimes I just can't be bothered to follow my own rules anyway. At one time, I was almost proud to be working 17-hour days.

When I do have a fit, if deadlines are tight, I continue work after a 10-minute break. Otherwise I go home to sleep. I ask people to remind me about the seizure, because some times I completely forget, which can be the after effect of my fits. And there is nothing worse than being at home and suddenly getting a flashback to something that you cannot remember.

If you find you are working with someone who has epilepsy, ask them if they have seizures at work and what they would like you to do, because everybody's experience is different. The important things are to put something soft under their head to prevent injury, make sure they are not lying somewhere dangerous - like the top of a flight of stairs - and don't put anything in their mouth.

All I ask for is an acceptance that it is OK to have the occasional seizure, just as it is OK for others to have a migraine or stomach upset. And I assure people that if I do have a seizure, they don't need to clear the room or call an ambulance. Usually, it is only ignorance that causes problems, and the more someone with epilepsy can tell their colleagues about what to expect the better.