Joris Peeters did not go looking for a therapist. He went to the pharmacy for his mother’s prescriptions, saw a sign offering a free conversation with a psychologist in the back room, and, on his third visit, sat down. “If it had been a clinic with a form and a waiting list, I would never have gone,” said Mr. Peeters, 24, a warehouse worker who had spent months unable to sleep. “It was a chair next to the cough syrup.”

Belgium’s first-line psychology program, which places licensed psychologists in general practices, pharmacies, community centers, schools, sports clubs and even a handful of cafes, has grown since 2021 into what public health researchers describe as the largest experiment in Europe in bringing mental health care to where people already are. Figures released by the federal health insurance agency this month show that 1,900 psychologists are enrolled, that they delivered 620,000 sessions in the past year, and that the median wait for a first appointment is six days, compared with 11 weeks for specialist mental health services in 2020.

Adults pay 11 euros for a session, children and students 4 euros, and the first session is free. Each person may use up to 20 sessions a year, and no referral is needed. The federal government budgeted 200 million euros for the program this year, about 1 percent of its health insurance spending on mental health.

“The old system asked a person in distress to recognize that they were ill, find a provider, get a referral, pay 60 euros and wait three months,” said Prof. Hanne De Smet, who studies health systems at the University of Antwerp and is evaluating the program for the government. “Each of those steps lost people, and it lost the people who needed it most. The design here is to remove the steps.”

Her team’s interim report found that 44 percent of the program’s users had never previously sought any mental health care, and that emergency psychiatric visits in the Antwerp region fell by 8 percent over three years while rising in neighboring regions where the program was slower to start. She cautioned that the association could have other explanations and that the program’s effect on the severely ill was unproven. “This is for the person with anxiety, grief, a divorce, a bad year,” she said. “It is not a substitute for a psychiatric hospital. It is a way to make sure fewer people need one.”

Dr. Lotte Van den Broeck, a clinical psychologist who works two days a week from a pharmacy in Antwerp’s Borgerhout district and three from a family practice, said the settings changed who walked in. At the pharmacy she sees older men and migrants; at the practice, mothers and teenagers. “The men would not sit in a waiting room with a sign that said ‘psychologist,’” she said. “They will sit in a pharmacy, because everyone is at the pharmacy for something.”

The program is not without critics. The association of psychiatrists has argued that it diverts money from specialist care, where waits remain long, and some psychologists in private practice complain that the state-set fee of 75 euros per session, of which the patient pays 11, is below their usual rates. Delegations from the Netherlands, Ireland and Portugal have visited this year, and the Irish health service said it would pilot a version in Cork in 2027.

Mr. Peeters used nine of his 20 sessions and said he was sleeping. “I still buy my mother’s pills there,” he said. “Now I say hello to two people.”