PORTLAND  — High on a drug called Monkey Dust, the 31-year-old man imagined people were crawling out of his mattress and coming to kill him. Panicked and paranoid, he grabbed his assault-style rifle and ammunition, ran out of his apartment and disappeared into the streets of Bangor, scaring his ex-girlfriend so much that she called police.

When officers later found the man standing on a street corner, he led them to his weapon. Apparently scared of how he was acting and what he might do, Christopher Thompson had dismantled the gun, wrapped it in a blanket and stashed it — along with a full magazine and 18 rounds of ammunition — in an abandoned shack. He was charged with carrying a concealed weapon.

Officials say that episode July 26 was no isolated incident. Across Maine, police and hospitals are reporting a surge of people becoming delusional and violent after injecting, snorting or smoking so-called bath salts, a synthetic drug that officials say is marketed under names including Monkey Dust, Monkey Mess, K2 and Vanilla Sky.

The Northern New England Poison Center received 110 calls — 87 from Maine, 17 from New Hampshire, four from Vermont and two from places unknown — between January and July from hospitals and individuals reporting instances of people in need of help after taking the drug. Last year, the center got only one call, in November.

Lawmakers passed a bill last spring making bath salts illegal in Maine. The blitz of cases in Bangor prompted the police chief to say problems have reached “epidemic” proportions there.

“It’s a daily occurrence,” said Bangor police Sgt. Paul Edwards. “Two to five or six times a night, we’ll deal somebody admitting to being on bath salts or Monkey Dust. It just seems that we’ve gone from nothing to this rage, this outpouring of cases of people on bath salts.”

Bath salts are unregulated psychoactive substances that provide highs similar to those from amphetamines, Ecstasy and cocaine. For the most part, they’ve been available on the Internet and in specialty smoke shops, officials say.

Bath salts, along with other designer synthetic drugs, have recently taken hold in the U.S. Officials say they’ve become popular because they’re accessible and inexpensive. For the most part they’ve also been legal, though Maine and a number of other states have now outlawed them.

People who take the drug report feeling euphoric and energized. But those who take too much can hallucinate and experience elevated heart rates, elevated blood pressure and high body temperatures, making them feel like their bodies are racing or on fire.

When people on bath salts become combative, it can take four or five people to subdue them, said Karen Simone, director of the Northern New England Poison Center. In some cases hospital staff have had to put them into light comas with heavy doses of sedatives to get them under control.

“What’s a little bit different about bath salts is you have this violence and this paranoia that creates situations in which you not only have to deal with medical issues, but you also have to deal with the safety of the community and other people in the emergency department. One of our hospitals had to hire 24/7 security officers for its emergency department to deal with this so patients and families who were there for other reasons could feel safe,” Simone said.

Reports of bath salts have come from around the state, Simone said, and she recently starting getting calls from hospitals in northern Maine. But Bangor seems to be experiencing the most cases, with several more also reported in the Rockland and Augusta areas.

Police and hospital officials say people high on bath salts have darted out in front of cars, attacked vehicles with shovels and flailed out at whoever happens to be there. Last month in Bangor, a 26-year-old woman was arrested after a couple reported she was following them on a street; she told police she was on bath salts and thought she was in outer space and wanted to be with her friends on Earth.

A couple of days later, police arrested a 32-year-old man after he crashed a service at a funeral home and was found running around threatening people, getting in their faces and acting delusional. He told police he was on bath salts when he was arrested and jailed, and he was found dead in his cell a short time later. Autopsy results are inconclusive on the cause of death pending the results of toxicology tests.

Pen Bay Medical Center in Rockport saw several dozen cases involving bath salts this spring, said Dr. Chris Michalakes, the hospital’s chief of emergency medicine.

After several episodes where people high on bath salts struck out at hospital staff and patients in the emergency room, the hospital increased its security and met with local law enforcement officials.

There’s been a drop-off as of late, but Michalakes said he’s still concerned.

“It really sort of snuck up on us,” he said. “We hadn’t seen any in Maine until this year and it’s creeped through the state. It showed up in very rapid fashion.”