(CNN) -- After their mother died in 2010, Brooklyn sisters Jennifer Parham and Melissa Grubb didn't speak for three months.
It wasn't the first time there was tension between them. Fights they'd had as teenagers (real fights, complete with hair-pulling, Parham says), had been replaced with squabbles over major decisions, such as how best to raise their younger sister, Tara, when their mother became seriously ill.
Eventually Parham and Grubb became fed up with the silences and missed having each other around, so they made the decision to attend counseling together to work out their differences, a move they say changed their lives for the better.
After meeting with a counselor for about two years (at first once a week and later once a month), they have learned to communicate in a more productive way, they say, and even started having meals together after therapy sessions, a detente that would never have happened before they sought outside help.
"No matter what our differences are, we love each other, and our relationship is more important than the differences we have," Parham, 34, says. "For us to have a connection trumped the differences we had with each other. I now know how to talk to Melissa, and I can accept she's completely different from me, as I am from her."
The stigma associated with therapy has reduced significantly in the past several decades, says Doug Pettinelli, a child and family psychologist and director of the Center for Counseling and Family Therapy at Saint Louis University. Yet while marriage counseling is booming, it's not as common for siblings to seek counseling to improve their relationship. Couples seeking marriage counseling across the country outnumber sibling pairs 10 to one, Pettinelli says.
There are several reasons behind this discrepancy, says Tziporah Rosenberg, an assistant professor of psychiatry and family medicine at the University of Rochester. Siblings may not feel the same urgency to improve their relationships as couples do, she says. Romantic partners or spouses have closely intertwined daily lives that can include children and shared money. It's uncommon for adult siblings to be as close, especially if they live far apart.
As a result, siblings tend not to "invest" in their relationships the same way couples do, Rosenberg says: "(Siblings) don't scream at you like an angry partner does, or they don't make a mess of your life in the same way. At least not in the immediate sense."
Conflict between siblings may arise because "they can push each other's buttons worse than anybody alive," says Jane Isay, who conducted almost 100 interviews with siblings for her book "Mom Still Likes You Best: Overcoming the Past and Reconnecting with Your Siblings."
Isay has seen siblings fight over issues as diverse as changing political parties and marrying the "wrong" spouse. But money takes the cake: Most siblings she sees are fighting over an inheritance or family assets. In fact, experts say the number one cause of rifts between siblings is money, also a leading cause of divorce.
"If you want to leave a broken family, write a will that leaves somebody out or that is unfair," Isay says. "When parents are ill and dying, this is an opportunity for siblings to come together and bond for the rest of their lives, or for resentments to build up for the rest of their lives."
Amy Warner, 26, of Arlington, Texas, says money was a factor in her strained relationship with her older sister.
"When she grew up she did not have as much money as I did when I grew up," Warner says. As a result, she says, her sister asks, " 'Why does she get things I didn't get growing up?' " The refrain has caused a rift.
Oftentimes, adult issues are not so different from the ones siblings face as children, but they no longer have parents around to play the referee, says Peter Goldenthal, a clinical psychologist and family therapist who is the author of "Why Can't We Get Along: Healing Adult Sibling Relationships."
In his experience, adult siblings' arguments seem to be grown-up versions of juvenile ones, such as who is the parents' favorite or who received a better holiday present. "I wonder if we ever really grow up," Goldenthal says.
Letting sibling bygones by bygones
To truly heal an injured relationship between siblings, experts say it is important to strike the appropriate balance between discussing past issues and moving on. Some therapists are more inclined to dig into past sibling issues, and others focus more on the present, Rosenberg says. Both techniques can be effective.
Each sibling must decide how much to engage with previous wrongdoing with the intention of moving on. To that end, Isay recommends for feuding siblings to never to start a sentence with the phrase, "You always ..."
"That just brings up old things," she says.
Reverting to old patterns can be hard to avoid, especially in situations that are stressful in the present, according to Rosenberg. "Touching a hot spot or button that's old might trigger us to interact in ways that ... aren't necessarily helpful," she says, which she calls the most "slippery" part of the relationship between adult siblings.
It is also helpful to speak for oneself and not involve others' opinions in the conversation, Rosenberg says. The goal should be identifying one's own feelings of hurt, then fully listening to the other sibling's perspective.
Playing nice for the kids
When feuding brothers and sisters have children of their own, trying to behave civilly can become even more important.
"Children watch their parents like hawks," Isay says. "If children -- even grown children -- see their parents reconnect with their siblings, they are thrilled. You can't teach your children anything by language if your behavior contradicts it."
Parents should avoid speaking about their siblings negatively and always remember the children are their siblings' nieces and nephews, Goldenthal says.
"If (siblings) are not getting along, it could be a really natural impulse to say, 'We're not doing anything about that relationship,' " Rosenberg says. "Kids could be stripped of those relationships and part of that is inherently unfair."
Although at one time it was unimaginable, Parham and Grubb are now training together to run a November marathon in memory of their parents. Their sons have bonded as cousins and choose to spend special occasions such as Halloween together.
"They adore each other," Grubb, 36, says.
The sisters meet with their therapist now only when they feel it is necessary.
"Jenny's married and has her son, I have my son and we have our younger sister, and that's it," Grubb says. "It's a very small family, and we understand we have a gift in each other. (It's important) to really cherish that and work as hard as we can to continue a relationship we can enjoy."
Amy Warner's experience with family counseling did not go quite as well. After trying a few sessions, family relations became so tense that she and her sister opted not to continue. They haven't spoken in months.
"I would be more than willing to try counseling again even though it ended horribly," Warner says. "I haven't gotten any sort of sign that she desires a relationship with me at this point. ... It is really important for both people to want a relationship."
Sibling relationships are often the longest-lasting bonds in life, Isay says, which adds to their importance.
"These are the people you will have known the most in your life, who sang the songs in the back of the car, who know the name of your first dog," she says. "Nobody else in your life shared those experiences."
Have you sought counseling along with a sibling to heal your relationship? What was the outcome? Share your experiences in the comments section below.