Doctors suspect that the condition is partially hormonal and may be triggered by lack of sleep. Men also have fewer support systems to fight off the depression.
"During pregnancy and after the child is born, a man's hormones change dramatically -- it's sort of a double whammy," Courtenay said. "Not only does testosterone go down, but the estrogen levels go up."
At the same time, men experience increased prolactin levels, the hormone in pregnant women and nursing mothers, up until the baby is 1 year old.
Though researchers don't fully understand why this happens, he said they suspect it's "nature's way of helping fathers bond with babies."
Neurological changes caused by lack of sleep can also play a role in men's behavior after the birth of a child, according to Courtenay.
"A normally healthy adult goes without good night's sleep for a month and they begin to show signs of clinical depression," he said. "So the lack of sleep, combined with hormonal changes and can create a perfect storm."
But men don't handle the stress as well as their female counterparts, he said. "They are more likely to avoid, deny, distract or drink alcohol or take drugs in response to depression and anxiety ... that only compounds the problems unless they have healthy coping strategies."
Men have fewer friends and social networks and rely on them less, according to Courtenay. "They primarily rely on their spouse or female partner as primary support."
And if the woman is having difficulty with the same things, depression can escalate.
In Nederlander's case, he was accused of abusing Kupferman, which he denied at the time. His lawyer, Bernard Clair, did not return calls from ABCNews.com.
A judge granted a protection order for Kupferman in February 2008.
More recently, Nederlander was jailed for a day for allegedly pushing his 31-year-old girlfriend Nancy Okun's face into a taxi cab divider window last summer and yanking her hair to wake her in the middle of night. A hearing is set for April 2, according to the Post.
ABC attempted to obtain the court documents from the Manhattan Supreme Court to learn more, but was told by the court clerk that matrimonial records are sealed for 100 years.
Only Nederlander or Kupferman could have released the documents and only by giving their permission "in writing," according to the clerk,
Kupferman's current divorce lawyer, Bonnie Rabin, refused to comment, except to say, "For sure, that was not us."