Nov. 7, 2011 -- Philip Mandel grew up walking on eggshells. His father -- a doctor adored by his patients -- was miserable and often mad at home.
"He'd come home, say hi to everyone then go take a nap," said Mandel, 58, who lives in Beaverton, Ore. "He was always quiet unless he was angry."
Although it was never diagnosed, Mandel suspects his dad suffered from depression -- a mood disorder that affects one in ten American adults.
"As a consequence I grew up being quite very shy," said Mandel, "even depressed."
Depression is known to run in families, but most of the research has focused on the influence of moms. Today, a study published today in the journal Pediatrics suggests children of depressed dads are more likely to have emotional or behavioral problems, such as feeling sad or acting out.
The study, based on a survey of nearly 22,000 children aged 5 to 17 and their parents, found that 11 percent of children whose fathers had symptoms of depression had emotional or behavioral problems, compared with only 6 percent of children whose parents had no depressive symptoms.
"What's even more remarkable than the results is the fact that this had never been looked at before," said study author Dr. Michael Weitzman, professor of pediatrics and psychiatry at NYU Langone Medical Center. "I think fathers are underrecognized in terms of the impact they have in families and in children's lives. It behooves us to try and devise clinical services that would identify fathers that are depressed and figure out ways to link them to services."
The rate of emotional or behavioral problems rose to 19 percent in children who had a mother with depressive symptoms, and 25 percent for children of two depressed parents.
While depression is known to have strong genetic roots, it is also thought to change how parents interact with their kids.
"The same things that make parents excited about their kids when they feel good can exacerbate their depression when their unhappy," said Weitzman. "One can only postulate that treating the parents could have a positive effect on their children."
Alan Kazdin, professor of psychology and director of Yale's Parenting Center and Child Conduct Clinic, said the study affirms the role of both parents in children's wellbeing.
"This may be the first study in fathers, but it fits in with a lot of other studies," he said. "It's nice to see we're getting away from just bashing moms."
It's uncertain whether depression in dads actually causes emotional and behavioral problems in kids -- the opposite could in fact be true, said Kazdin.
"But one of the best things you can do for your children is maintain your physical and mental health," said Kazdin. "You say you'd do anything for your child? So go get treatment. It will make a difference in how you interact with your child."
Mandel said his dad's depression made him nervous and anxious.
"I was always leery about what I could or couldn't say; what I could or couldn't do," he said, describing his dad's hot temper. "When he was angry, I was terrified. I was just a kid."
Mandel's dad died from heart disease in 1980.
With treatment, Mandel overcame his shyness and depression in his 40s.
"You grow up in your household thinking your parents are normal. But you go to other people's houses and their dads and moms are joking around; everyone's having a good time," he said. "It was definitely not good role modeling."
Although he's an electrical engineer by training, Mandel now works as a health coach, helping others take charge of their health.