It seems that men and women can't agree – even when asleep.
A study of dreams found that even in the dead of night, the sexes are thinking about different things.
While men have nightmares about fires, floods, wars and other disasters, women are jolted awake by thoughts about rows, lies and infidelity.
Canadian researchers asked more than 300 men and women to write down the content of their dreams on waking each morning for up to five weeks.
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Researchers found men dream of fires, wars and disasters while women think about lies, rows and infidelity
They then zeroed in on nightmares – in which the person woke up mid-dream – and bad dreams, which while still disturbing were less intense.
Diary entries on nightmares were longer than those for bad dreams and women wrote longer descriptions of their bad dreams than men.
Nightmares were dominated with scenes of physical aggression, including kidnappings and murders. Rows and fights, humiliation, infidelity and other forms of 'interpersonal conflict' formed the second most common theme.
Feelings of failure and helplessness, including being late or lost, were also common, as were nightmares in which the dreamer became ill or died.
Many also jolted awake after believing they could see or feel the presence of an evil force such as a monster, alien, vampire or ghost.
The men studied were twice as likely to have nightmares or bad dreams about disasters. They were also plagued by images of infestations of insects.
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Diary entries on nightmares were longer than those for bad dreams and women wrote longer descriptions of their bad dreams than men
The women, in contrast, were more likely to have nightmares about rows, broken friendships and relationship fears, including infidelity.
The study's authors, from the University of Montreal, said: 'Dreams of interpersonal conflicts may elicit a more intense emotional response thin women, leading to a greater proportion of such dreams ending in a nightmare awakening.'
Writing in the journal Sleep, they added that their research is especially informative, as it used diary entries rather than tick list-type questionnaires to log the content of people's dreams.
It is thought that everyone dreams. Most people forget them straight away but heavy sleepers have better recall.
Researcher Antonio Zadra said that nightmares can have serious consequences for health.
He said: 'Nightmares are not a disease in themselves but can be a problem for the individual who anticipates them or who is greatly distressed by their nightmares.
'People who have frequent nightmares may fear falling asleep – and being plunged into their worst dreams.
'Some nightmares occur every night.
'People who are awakened by their nightmares cannot get back to sleep, which creates artificial insomnia.'
