Differences between men and women are always debated when it comes to categories like dating, sex and food. But now experts have added another category where the sexes diverge- dreams.

Scientists at the University of Montreal have conducted a study of 10,000 dream reports from 572 men and women, The Telegraph reported.

Researchers found that men and women tend to dream about different themes. Women dreamed about conflicts with social relationships, such as a friend or a significant other. Men on the other hand were "significantly" more likely to dream about disasters, such as swarms of insects or wars.

The study, recently published in the journal SLEEP, also observed differences between the nightmares and bad dreams the respondents had. Scientists found that while men and women have the same number of bad dreams, nightmares had a greater emotional influence on the subject than bad dreams, The Telegraph reported.

In other words, nightmares had themes of physical harm and evil while bad dreams were about interpersonal disputes.

"Physical threats are more likely to characterize nightmares whereas psychological threats, including threats to self-esteem, are more prominent in bad dreams," the study said, according to The Telegraph.

A key difference between nightmares and bad dreams is that nightmares tend to wake the dreamer up because they are so disturbing. Bad dreams do not make the person wake up.

Though they are disturbing, however, researchers also found that nightmares are not always about being scared of something.

"Death, health concerns and threats are common themes in nightmares, but it would be wrong to think that they characterize all nightmares," Geneviéve Robert, the head author of the study, said according to The Telegraph.

Almost half the 431 bad dreams and 253 nightmares studied were about sadness, anger and frustration, The Telegraph reported.

"Sometimes, it is the feeling of a threat or an ominous atmosphere that causes the person to awaken. I'm thinking of one narrative, in which the person saw an owl on a branch and was absolutely terrified," Robert said.