A lot of women are unaware that men go through a period too that affects their behavior. It's a bit like women period and it's called IMS.
A man's period is essentially related to his level of Testosterone. This Hormone affects his behavior and unlike women, he feels the symptoms any time and not just monthly.
Men period is a bit different from women period, so they do not lose a lot of blood, but it will lead them to mood swings, depression, anger and low self-esteem.