A woman's stress is anything but easy, from juggling work to taking care of family to upholding her appearance. A new book reveals that it can take a true psychological toll on her health.

The Stressed Sex: Uncovering the Truth about Men, Women, and Mental Healthwritten by Jason Freeman, a professor of clinical psychology and senior clinical fellow of the Medical Research Council at the University of Oxford, was published on Thursday.

Freeman's investigation found that psychological disorders are 20 to 40 percent higher in women than men.

Women suffer from higher rates of depression, panic disorders, phobias, insomnia, post-traumatic stress disorder, and eating disorders.

Freeman believes society demands have put a burden on women and likely cause these greater levels of stress. "Increasingly, women are expected to function as carer, homemaker, and breadwinner - all while being perfectly shaped and impeccably dressed," he told the Daily Mail.

"Given that domestic work is undervalued, and considering that women tend to be paid less, find it harder to advance in a career, have to juggle multiple roles, and are bombarded with images of apparent female 'perfection', it would be surprising if there weren't some emotional and psychological cost."

Men, on the other hand, show more problems with anger management and alcohol and drug abuse, though depression also affects a significant number of men. 

According to Psychology Today, depression in wealthy countries like the United States and United Kingdom is not surprising and is dubbed "the common cold of psychiatry."

Experts believe that biology and aspects of psychology and society could explain why depression is significantly greater in women than men. For instance, a woman's hormones are subject to shift during pregnancy and at menopause, which already puts them at a greater risk of depression.

Women also invest more in their relationships than men do. They are also more likely to seek help from clinicians if they're depressed, which could factor into why they are more diagnosed.

Freeman also stressed that getting paid less than men and struggling to advance in careers is another contributing factor. Wage and hiring discrimination against women is a problem that often goes unnoticed. In 2012, women's wage was only 82.2 percent of men's, while their yearly salaries were 77 percent of what men earned, reported Bloomberg Businessweek

A study by researchers last year at Yale University revealed another twist: female professors show the same bias as males against women students in their classrooms. Furthermore, these professors are less likely to offer a position to women, especially for a high-salaried job.

"These are the kind of pressures that can leave women feeling as if they've somehow failed; as if they don't have what it takes to be successful; as if they've been left behind," said Freeman. "And those kinds of feelings can lead to psychological problems like anxiety and depression."

Freeman added that differences between men and women should be researched even further, rather than be marked as a taboo, in order to provide better treatment plans in the future. Gender disparities in mental health could be a decisive factor of psychological disorders.