JI-PARANÁ, Brazil — As the night sky enveloped this outpost in ’s Amazon basin, the ceremony at the open-air temple began simply enough.
Dozens of adults and children, all clad in white, stood in a line. A holy man handed each a cup of ayahuasca, a muddy-looking hallucinogenic brew. They gulped it down; some vomited. Hymns were sung. More ayahuasca was consumed. By midnight, the congregants seemed strangely energized. Then the dancing began.
Such rituals are a fixture across the Amazon, where ayahuasca has been consumed for centuries and entire religions have coalesced around the psychedelic concoction. But the ceremony one night this month was different: Among those imbibing from the holy man’s decanter were prison inmates, convicted of crimes such as murder, kidnapping and rape.
“I’m finally realizing I was on the wrong path in this life,” said Celmiro de Almeida, 36, who is serving a sentence for homicide at a prison four hours away on a road that winds through the jungle. “Each experience helps me communicate with my victim to beg for forgiveness,” said Mr. de Almeida, who has taken ayahuasca nearly 20 times at the sanctuary here.
The provision of a hallucinogen to inmates on short furloughs in the middle of the rain forest reflects a continuing quest for ways to ease . The country’s inmate population has doubled since the start of the century to more than 550,000, straining underfunded prisons rife with and violent uprisings complete with .
One of the bloodiest prison revolts in recent decades took place in the nearby city of Pôrto Velho, in 2002, when at least 27 inmates were killed at the Urso Branco prison. Around the same time, Acuda, a pioneering prisoners’ rights group in Pôrto Velho, began offering inmates therapy sessions in yoga, meditation and Reiki, a healing ritual directing energy from the practitioner’s hands to a patient’s body.
Two years ago, the volunteer therapists at Acuda had a new idea: Why not give the inmates ayahuasca as well? The Amazonian brew, which by blending and boiling a vine (Banisteriopsis caapi) with a leaf (Psychotria viridis), is in , the United States and other countries.
Acuda had trouble finding a place where the inmates could drink ayahuasca, but they were finally accepted by an offshoot here of Santo Daime, founded in the 1930s that blends Catholicism, African traditions and the trance communications with spirits popularized in the 19th century by a Frenchman known as Allan Kardec.
“Many people in Brazil believe that inmates must suffer, enduring hunger and depravity,” said Euza Beloti, 40, a psychologist with Acuda. “This thinking bolsters a system where prisoners return to society more violent than when they entered prison.” At Acuda, she said, “we simply see inmates as human beings with the capacity to change.”
Ms. Beloti and other therapists test aspects of this philosophy at a compound in a sprawling prison complex in Pôrto Velho. Judges and wardens allow about 10 inmates from maximum-security prisons in the city to live in the Acuda building, a former army installation. Dozens of other prisoners from surrounding penitentiaries attend Acuda’s therapy sessions each day.
Inside the compound, the inmates practice meditation. They perform ayurvedic massage on one another. They learn skills like motorcycle maintenance. A furniture workshop gives them access to tools like saws, hammers and drills. And they tend a garden, growing vegetables and the plants used to make ayahuasca.
Treating inmates with psychedelic drugs anywhere is thought to be rare. In one short-lived in the United States in the early 1960s, researchers from Harvard University under the direction of the psychologist gave psilocybin, a drug derived from psychoactive mushrooms, to inmates at a prison in Concord, Mass.
“It’s certainly novel among prisoners, but ayahuasca has great potential because under optimal conditions, it can produce a transformative experience in a person,” said Dr. Charles S. Grob, a professor of psychiatry at the U.C.L.A. School of Medicine who has conducted extensive studies on ayahuasca.
Dr. Grob cautioned that there were risks. The brew could exacerbate the illnesses of people being treated with antipsychotic medications for or . Ingesting drugs like cocaine or methamphetamine before consuming ayahuasca is also dangerous.
“That would be a disaster, because the individual could have a hypertensive reaction leading to a stroke,” Dr. Grob said.
The supervisors at Acuda, who obtain a judge’s permission to take about 15 prisoners once a month to the temple ceremony, say they are mindful of the risks of ayahuasca, commonly called Daime in Brazil or referred to as tea. At the same time, Acuda’s therapists consume the brew with the inmates, as well as with the occasional prison guard who volunteers to accompany the group.
“This is how it should be,” said Virgílio Siqueira, 55, a retired police officer who works as a guard at the prison complex that includes Acuda. “It’s gratifying to know that we can sit here in the forest, drink our Daime, sing our hymns, exist in peace.”
Many people in Brazil, where conservative politicians are as they vow to crack down on crime in a country with per year than any other, remain unconvinced. Therapists who volunteer at Acuda said they had lost clients in their private practices who disagreed with providing such attention to convicts. Some relatives of victims who suffered at the hands of the Acuda prisoners contend that the project is unfair.
“Where are the massages and the therapy for us?” asked Paulo Freitas, 48, a manager at a leather factory whose 18-year-old daughter, Naiara, a college student, was kidnapped, raped and murdered in Pôrto Velho in 2013 by a group of men, a crime that many people in this corner of the Amazon.
Mr. Freitas said he had been shocked to learn recently that one of the men convicted in the killing of his daughter was expected to be transferred soon into Acuda’s care. “This is utterly revolting,” he said. “My daughter’s dreams were extinguished by that man, but he will be allowed to go into the jungle and drink his tea.”
Others question whether consuming Daime can help lower re-incarceration rates. Luiz Marques, 57, an economist who founded Acuda, said the organization hoped to reduce recidivism, but he emphasized that a more immediate goal was “expanding the consciousness” of prisoners about right and wrong.
At the temple here in Ji-Paraná, the inmates appeared to experience a range of reactions after drinking the ayahuasca. Sitting on plastic lawn chairs under a tile roof, some were stone-faced. Others seemed lost in contemplation. One was constantly in tears, as if demons were at the door. All of them sang at the top of their lungs when the rhythm of the hymns intensified.
“We are considered the trash of Brazil, but this place accepts us,” said Darci Altair Santos da Silva, 43, a construction worker serving a 13-year sentence for sexual abuse of a child under 14. “I know what I did was very cruel. The tea helped me reflect on this fact, on the possibility that one day I can find redemption.”