Men are also susceptible to experiencing sadness, tearfulness or irritability after sexual activity. The phenomenon, known as postcoital dysphoria (PCD), has previously only been recognized in women according to researchers from Queensland University of Technology (QUT) in Australia.

The paper titled "Postcoital Dysphoria: Prevalence and Correlates among Males" was published in the Journal of Sex & Marital Therapy on July 24.

"The first three phases of the human sexual response cycle — excitement, plateau, and orgasm — have been the focus of the majority of research to date," said Robert Schweitzer, a professor at the School of Psychology and Counseling at QUT. As a result, the fourth and final stage of the cycle — the resolution phase — remains a poorly understood experience.

Previous research that did look into PCD largely focused on its prevalence and effect among women, making this a "world-first" study according to the authors.

An international survey was conducted, involving more than 1,200 men from 78 countries including the United States, Australia, the United Kingdom, Russia, New Zealand, Germany etc.  

The results revealed that 41 percent of men experienced PCD at some point in their lifetime while 20 percent experienced it over the month leading up to the survey. But only 4 percent of respondents reported experiencing PCD on a regular basis.

When asked about how they felt, some respondents explained that they did not want to be touched and wanted to be alone after sex. Others reported feeling unsatisfied and irritable.

"All I really want is to leave and distract myself from everything I participated in," one respondent said, while another used words like "emotionless" and "empty" to describe their post-coital experience.

Generally, couples who report high levels of satisfaction from a relationship tend to engage in activities like cuddling, kissing, and having conversations after sex. So the resolution phase is considered to be important for bonding and intimacy, said Joel Maczkowiack, a master's student at QUT who also worked on the study.

The findings indicated that the resolution phase experienced by men is just as varied and complex as it was found to be in women. "We would speculate that the reasons are multifactorial, including both biological and psychological factors," Schweitzer said.

Hormonal shifts after an orgasm (i.e. coming down from an immense, pleasurable high) can explain the sadness in some cases. Others may simply have a preference for keeping to themselves after the act.

It was also noted that western culture may have driven assumptions about the way men should perceive and experience sex. "These assumptions are pervasive within masculine sub-culture and include that males always desire and experience sex as pleasurable," he said. 

The authors hoped that the study could encourage conversations about the expectations surrounding men and sexual activity, which could influence future therapies.