Fewer patients are undergoing in-depth treatment as antidepressants and other drugs are more widely used. The shift is attributed partly to insurance reimbursement policies.

Wider use of antidepressants and other prescription medications has reduced the role of psychotherapy, once the defining characteristic of psychiatric care, according to an analysis published today.

The percentage of patients who received psychotherapy fell to 28.9% in 2004-05 from 44.4% in 1996-97, the report in Archives of General Psychiatry said.

Researchers attributed the shift to insurance reimbursement policies that favor short medication visits compared with longer psychotherapy sessions, and to the introduction of a new generation of psychotropic medications with fewer side effects.

Although not a surprise to many psychiatrists, the findings were expected to intensify a debate over the increased medicalization of psychiatric care, which in part reflects an emphasis on the biology of mental illness, as opposed to the processes of the mind.

Psychotherapy is an interpersonal intervention that may involve such things as behavior modification and group discussion. It is recommended -- with or without medication -- for major depression, post-traumatic stress disorder, bipolar disorder and other psychiatric illnesses.

Besides psychiatrists, a range of mental health professionals not covered in the report also conduct psychotherapy, including psychologists, social workers and marriage counselors.

The study was based on data drawn from the National Ambulatory Medical Care Survey, an anonymous survey of office-based physicians that tracks characteristics of patients and physicians, and records the diagnosis and treatment, during a typical week.

Researchers examined data on 14,108 psychiatric office visits during a 10-year period.

Psychiatrists who said they provided psychotherapy to all of their patients declined to 10.8% in 2004-05 from 19.1% in 1996-97, according to the report. Consistent with previous studies, researchers found that patients who paid out of pocket, generally the wealthiest patient group, were more likely to receive psychotherapy.

Financial incentives were weighted against psychotherapy, the report said. Reimbursement for a 45- to 50-minute outpatient psychotherapy session was 40.9% lower than reimbursement for three 15-minute medication management visits, the report said, citing a 2003 study. Anticipated changes in Medicare reimbursement are expected to bring payments into closer balance, experts said.

Also fueling the trend, according to the report, was the aggressive marketing of psychotropic medications to psychiatrists and patients. That push, for example, has helped make antidepressants one of the largest-selling classes of drugs.

Dr. Mark Olfson of Columbia University Medical Center, a study author, said patient attitudes might also be hastening the shift. Taking a pill may look a lot easier to patients than psychotherapy, which is more time-consuming and may involve the regular participation of family members.

The report found evidence of a cultural preference for psychotherapy in the Northeast, which Olfson said might be attributable to the influence of the Yale School of Medicine and the University of Pennsylvania School of Medicine, whose faculties are strong proponents of psychotherapy.

Because the study looked only at psychiatrists, it couldn't determine whether patients who needed psychotherapy were receiving it from other mental health providers or going without treatment, Olfson said.

Dr. William H. Sledge, interim chairman of the department of psychiatry at Yale, said the report was worrisome. Although training in psychotherapy is a standard part of psychiatric training, he said, the know-how is in danger of becoming lost.

"A group of practitioners is losing an important skill. It is like going to war with fewer weapons at your disposal," Sledge said.

Dr. Alan F. Schatzberg, chairman of the department of psychiatry at Stanford University School of Medicine and president-elect of the American Psychiatric Assn., said the trend was not necessarily bad. It could be seen as a natural evolution, similar to what is seen in other fields of medicine.

"Years ago, if someone had a herniated disk, they had a very complicated surgical procedure and were in traction for weeks," he said. "Fields change. What we don't want to do is decide treatment based on reimbursement."