First-Hand: My exhaustion is killing my patients: Junior hospital doctor Maria is terrified at the consequences of the 120-hour weeks she works

I KNOW some of my patients have died because I've been so chronically tired. I've given patients drugs they shouldn't have had, or given them too many drugs. Or I've given them the wrong diagnosis. You get to the stage when you literally cannot function. I know I'm not the only doctor to feel this terrible guilt. It's devastating.

I'm 29 now, and have been working as a junior doctor for five years. In addition to my routine responsibilities (I cover wards in three different hospitals), I'm often also covering emergency admissions, or administering new drugs which are extremely sophisticated and need to be monitored carefully.

During the period I'm on call, I'm responsible for about 200 people. Technically, I can ring the consultants at home if I need to, but I try not to. Because they are responsible for giving me my final reference before I go on to my next job I don't want to ruin the impression I've created that I can cope. But on occasions I've gone 56 hours with no sleep.

On a normal weekday I will start work at nine in the morning. If I'm on call that night all my colleagues will go home at five o'clock, and I'll go on working all night. Then when I've finished being on call the following morning I have to start another normal working day, finishing at five that evening. It's quite possible for me to do a 120-hour week. At the end of the day, overtime included I suppose I get paid around pounds 27,000 a year.

My job is very rewarding, and I love it. But after I had been working a couple of years, I became so severely depressed that I ended up in hospital as a patient myself.

I'd had years of what felt like continual jet-lag. My brain and body had short-circuited and, it seemed, given up the ghost. I'd never been depressed before but I suddenly found I couldn't eat or drink because I felt sick all the time. I lost three stone, and I got very paranoid too. If anyone said anything remotely critical to me I'd burst into tears. I so wanted to sleep in the mornings that I'd lie in bed for as long as I could, before stumbling off to work. I never bothered to look nice, or even iron my clothes a lot of the time. After a bit I started thinking of suicide. It was very frightening. I was scared of going near any sharp objects - I couldn't trust myself. All I could think of at the time was 'How can I get out of this situation?' I was so desperately unhappy all the time.

In hospital they put me on three different types of drugs and after nine months I started to get better. It was just at the time the Government was signing the agreement stating that junior doctors should try to work no more than 72 hours which made things easier too. That was about three years ago.

I'd like to settle down now, but it's very difficult to find friends outside the medical profession. Once you've got the relationship going you're out of action for all the time you're on call, and after you've been on call you're too tired and fed up to sustain being nice.

I've applied for another job. I want to retrain as a medical administrator. I'd still like to be involved in medicine but not clinical practice. But I cannot face another God knows how many years with the sort of pressures that I'm under.

I'm terrified for my patients if I carry on working as I have been. I regularly used to find this friend of mine bawling her eyes out. She was the anaesthetist in the intensive care unit, and was getting woken up every hour. The front-line person in that state? It's ridiculous.