The scene from the film Heat, Heat, in which Al Pacino, the policeman, and Robert de Niro, the gangster, discuss their respective recurring dreams over coffee, is a quick and easy way for the audience to gain some insight into the characters and their preoccupations. Pacino's character dreams he shares a table with every murder victim he has seen during his years as a policeman. They don't speak; they just look at him. De Niro's character dreams that he is drowning and has to wake up and breathe or die in his sleep.

It may be that Pacino's character is being confronted by the grotesque reality of what he failed to prevent or simply that traumatic events occupy his mind and therefore turn up in his dreams. De Niro's character, on the other hand, feels his dreams reflect his anxiety about not having enough time to do what he wants to do in life.

Dreams and their meaning, or lack of meaning, have occupied minds since people started recording them on papyrus, but it seems we still know relatively little about them or their significance. Recurring dreams related to one's job are a common occurrence which can lead to interrupted sleep, sweating or - on a good night - resolutions to crises.

Psychiatrist Dr Anthony Clare has encountered people who have had recurring dreams specific to their jobs. "I remember interviewing Dr Bernard Knight, the forensic pathologist on the West murders," recalls Dr Clare, "and he described dreaming about cutting up a body which would start to come alive or he would suddenly recognise it as a relative or loved one. He thought this was quite a common dream among pathologists and didn't seem to be too perturbed by it.

"I also had a patient a few years ago who was under a lot of strain and because he was an air traffic controller, he dreamt about near misses." Dr Clare does not think people who experience recurring dreams about work should consider leaving their job.

"It is natural for occupations to have an effect on dream content. But recurring dreams about work may indicate stress or problems in certain areas. It's not what people dream, but rather the frequency with which the dream occurs, that matters. And I would also look at all factors of the person's life." Dr Clare does not experience recurring dreams himself, but has experienced work-related dreams. "When I am away on holidays, I may have a certain amount of anxiety about some patients and then I might have dreams about not being able to get back to see them."

Life and death seem to be a feature of many recurring dreams. Dermot Doorly, who has been a structural engineer for nearly 50 years and is responsible for making sure that buildings stay up, explains why he still wakes up at night dreaming about calculations.

"If somebody wants to knock down an inside wall in a building, they ask me to check if it is a loadbearing wall and if a pillar or something else would be needed to replace it," explains Dermot. "I then have to calculate the weight per square foot and advise them on what they should do. If I get it wrong, it could have very serious consequences, so I think that's why I still wake up at night doing calculations of weight per square foot in my head. Sometimes I will even get up, go to my drawing board and check all the figures again. Also, if I am passing a building which I have worked on, I always pop in and have a quick look around for cracks," Dermot adds, laughing.

But it's not just life and death which cause people to wake from fitful sleep. Russell Phoenix, who works as a waiter in a busy Dublin restaurant, found himself having recurring nightmares about not being able to get to tables with plates of food. "It may not sound like the stuff of nightmares, but I would wake up sweating and in an awful state because no matter what I did or which way I tried to go, I just could not get to the table with the food. The pressure that waiters are under on weekend nights is almost unbearable."

Working for others and not being in control was obviously something that preoccupied hairdresser Colm O'Rourke, whose recurring dream went away when he became the owner of a hair salon. "I used to dream that I was working in a salon on Grafton Street and one floor was filled with my family and another floor was filled with my friends," says Colm. "I knew my family wouldn't approve of my friends so I was running up and down making sure they stayed on their different floors and didn't meet each other. I was also trying to do their hair at the same time. That dream went on for months but as soon as I became the owner of my own salon, it stopped."

Jasbinder Garnermann, from the Jung Centre on Dublin's Manor Street, who approaches recurring dreams about work from a Jungian perspective, sees them possibly as anxieties from elsewhere relocated to a familiar place. "The dreams speak in the language of the dreamer, so the symbols would be from their daily lives," explains Jasbinder. "The workplace is a wonderful setting for analysis. There is a woman who comes to see me, and all her dreams are set in the laboratory where she works. This is because the setting is familiar.

"If somebody comes to see me about a recurring dream, the first thing I do is get all the details of the dream and the context and if it is about something specific to the work, then that's the interpretation I would put on it. But sometimes, anxiety is carried from elsewhere and displaced onto work. Maybe it is a fear of failure, as fear of failure tends to cluster around everything. It could take a long time to analyse a dream completely but the dream often changes as the analysis goes on. Sometimes another figure appears in the dream and helps the person out."

Ross Skelton, a Lacanian psychoanalyst, believes that a recurring dream is like a question waiting to be answered. "As soon as the dream is analysed it ceases to occur," explains Skelton.

"The focus in Lacanian psychoanalysis is on talking. It's Freudian with attitude," he says. "Unlike Freudian analysis, which focuses mainly on the role of the mother, Lacanian analysis restores the father in the mind of the patient."

Dream analysis is a subject which often causes controversy Psychoanalysts and psychiatrists argue and disagree among themselves and with neuroscientists, and recently, neuroscientists have also begun to disagree with each other. Traditionally, scientists would dismiss dream analysis as unscientific and maintain that dreams are random, but recent studies have led some scientists to believe that dreams may not be random but may have some meaning after all.

Dr Catherine Crowe, a psychiatrist at the sleep disorder clinic on Eccles Street, Dublin, would see herself as having a foot in both camps. "I think that dreams are sometimes random and sometimes not. But I think the function of dreams is still inconclusive. We don't know enough about it yet, and a lot more research needs to be done."