The search is being conducted via police helicopter, on foot, with police dogs, volunteers in kayaks, and police officers asking questions of everyone and anyone who might have seen or heard something that could provide a clue.
Patric was last seen on Monday afternoon, only 300 yards away from his family's condo in the Clear Brook development, and had been playing with his stepbrothers, Gabe Fritz, 12, and Noah Fritz, 7, when the three boys decided to race back to the house.
Patric never turned up. Police believe he may have taken a wrong turn in the woods, where temperatures at night have dipped into the 30s, with wind and rain increasing the risk of hypothermia.
"Please, everyone, just never stop looking," said the boy's father, Steve McCarthy, who held a news conference Thursday with his wife, Margaret McCarthy, Patric's stepmother.
Her mother and friends flew in from Columbus, Ohio, to New Hampshire to be with the missing boy's brothers and pray for Patric as the search continues.
The McCarthys are from Bourne, Mass., as is Patric's mother, Dee Murray, whose father says she is so worried that she is now under a doctor's care.
The National Crime Information Center has registered Patric as a missing child and numerous possibilities are being investigated.
"There's absolutely no indication that he was abducted," says New Hampshire State Police Lt. John Scarinza. "Nobody has called with any information along those lines."
The Union Leader newspaper reports police are seeking video surveillance tapes from gas stations in town and have interviewed over 100 people who were in the vicinity on Monday.
Police reportedly have also checked the names of the residents of the condo development - the Clear Brook condominiums - and none are individuals who are on any list of known child predators.
"We're still upbeat and hopeful," said Fish and Game Captain Marty Garabedian Thursday night, updating reporters on the search.
The family went through a roller coaster of emotion Thursday as searchers found a baseball cap and a sweatshirt in the woods, items which officials later said did not belong to Patric.
"It was a rough day," said Margaret McCarthy. "We all melted down, but I feel positive again. If they feel Patric can survive, I have to."
The McCarthys are well-known in Bourne - the Cape Cod, Mass., town where they live - as owners of the Gray Gables Country Market, where a "God Bless You, Patric" sign now hangs. Neighbors there held a prayer vigil Tuesday night.
Among those praying for the 4-foot 10-inch, 85-pound fourth grader are classmates and teachers at the elementary school in Bourne.
"Our prayers certainly go out to his family for his safety," says school principal Don Morissey, who describes Patric as "never any trouble, just a great kid."
"We feel like maybe he's hiding somewhere, he's tired, he's exhausted, he can't really call out, and they're going to come across him," Josephine Bevilacqua, a friend of the family, told WBZ-TV.
Over 200 Bourne residents have made the decision to get in the car and drive the three and a half hours to New Hampshire to join the search.
Among them are Lizzie and Raymond Rioux, whose daughter is Patric's babysitter.
"I think God is leading the way now," Lizzie Rioux told the Union Leader. "We have to bring him home. We just have to bring him home."