As a funeral home director in Pittsfield, Rob Dwyer has worked with many grieving families.

But when a young girl became overcome with emotion and rushed out of her grandmother’s service, he called on a special staff member at Dwyer Funeral Home to help: Greyce, a 2-year-old Chesapeake Bay retriever.

“Just the presence of the dog changes the mood,’’ Dwyer said. “The dog walked out of the funeral and followed her and just sat down beside her. The tears stopped pretty quickly.’’

It’s a trend starting to grow among funeral homes in Massachusetts — offering the services of a therapy dog to comfort bereaved families during planning meetings, wakes, and funerals.

Therapy dogs are also offered by the Gately Funeral Home in Melrose, and at least six other funeral homes are currently training therapy dogs, according to Margaret Nolan, executive director of the Massachusetts Funeral Directors Association.

A spokesperson for the National Funeral Directors Association said that, anecdotally, the trend has increased within the industry, especially in the last four years.

Dwyer began working with Greyce nearly a year ago, and said it’s been “the best idea.’’

“It makes the whole event more comfortable. We were thinking it would be perfect for kids, but I wasn’t anticipating the reaction from adults,’’ Dwyer said. “Typically when the dog gets here I’ll introduce them to the family. I can not only feel [the difference] but see it in their faces, it changes the whole mood.’’

He added that Greyce’s presence, available upon request, also makes the experience positive for children who have never been to a funeral before.

“I know a lot of people who are adults who had bad experiences at funeral homes when they were kids and to this day they are scarred,’’ he said. “When these kids get older, their first experience at a wake is going to be a positive one, they’re not going to have those issues.’’

Melissa Sears, a Pittsfield resident, said that Greyce’s presence at her mother’s funeral was “a real comfort,’’ especially to the 15 grandchildren in attendance.

“It helped them get through the day and give them something else to focus on. Just the calmness of her being there helped a lot,’’ Sears said. “So many adults found time to find solace in Greyce. She put her head on my uncle’s lap out of nowhere. It made a big difference.’’

According to Dr. Deborah Linder, associate director of the Tufts Institute for Human-Animal Interaction, there could be a scientific explanation for the positive impact therapy dogs can have on grieving families.

“There are some studies that point to an actual physical change in the brain of humans after being with a therapy animal,’’ she said. “For those studied thus far, it appears that dogs can have a calming effect that actually changes our biology when we interact with them.’’

Those effects, Linder said, can include reduced blood pressure and anxiety. One study showed that humans had decreased stress hormones after just five minutes of interacting with a therapy dog.

The research comes as no surprise to John Gately, director of Gately Funeral Home. He has offered the services of his golden retriever, Tucker, for the past nine years. It started off as an experiment, after Gately guessed that his clients might enjoy interacting with his dog.

Tucker was a hit, and has since gone to work with Gately almost every day.

“Ninety percent of people absolutely love it. He’ll walk around the room, you’re just sitting there patting Tucker, this big fluffy dog,’’ he said. “I’ve seen him go to someone that is having the hardest time. I don’t know how he senses it, but he knows. There’s just something about him.’’

Catie Edmondson can be reached at catie.edmondson@ globe.com. Follow her on Twitter @CatieEdmondson.