More primary care physicians are prescribing antidepressants, but some observers worry that patients aren't being evaluated closely enough for potential adverse reactions or monitored appropriately while taking the drugs.

Research is beginning to show that "large numbers" of prescriptions for selective serotonin reuptake inhibitors (SSRIs) aren't accompanied by a diagnosis of depression or any other mental condition, said Stephen Crystal, Ph.D., a researcher who studies prescribing trends at Rutgers University in New Brunswick, N.J.

"We have a massive uncontrolled experiment going on out there," he said.

The number of doctor office visits including an antidepressant prescription more than doubled between 1985 and 1994 to more than 24 million, according to data from the National Ambulatory Medical Care Survey (NAMCS). Researchers attribute the rise to the popularity of SSRIs.

While an estimated 11 million psychiatrist appointments included an antidepressant prescription in 1994, more than 10 million other antidepressant prescriptions were written by primary care doctors. Preliminary analysis of survey data extending through 1996 shows that antidepressant prescriptions are now more common in primary care offices than in psychiatrists' practices, according to Dr. Crystal.

Managed care is at least partly responsible for the trend. Primary care physicians acting as gatekeepers in HMOs have been encouraged to treat potentially depressed patients rather than refer them to specialists. At the same time, primary care doctors are becoming more comfortable with the newer SSRIs because they are relatively easy to use.

Toxicity and overdoses are rare, and potential drug interactions are far less common than with other drug classes. The drugs may also provide a convenient way to treat somatizing patients who have a few depressive symptoms without a full-blown depressive episode.

But relatively few data exist to support SSRIs' efficacy in treating the "subthreshold" patients often seen in primary care. Many of those patients may get SSRIs without any official diagnosis, according to Dr. Harold Pincus, who last year published a study on psychotropic prescribing using NAMCS data.

Office-based psychiatry practices tend to aggregate around more affluent and better-educated patients in medium and large cities. Most observers agree that primary care's new dominance in antidepressant prescribing makes the drugs available to a wider range of patients.

"Those who are underserved by specialists are nonwhite and not wealthy. They are the ones who benefit most from primary care physician prescribing," said Dr. Gregory Simon, a psychiatrist who studies prescribing patterns at Group Health Cooperative of Puget Sound in Seattle.

The American Psychiatric Association recommends in its depression treatment guidelines that patients continue their SSRI prescription for 4-5 months after complete remission of their symptoms. But data from Group Health Cooperative--an HMO that emphasizes primary care treatment of mental conditions--show that only 34% of patients on SSRIs refill their prescriptions often enough to suggest continuous use.

At the same time, new data from the Rutgers group show that Medicare patients treated in primary care are more than twice as likely as similar patients treated in psychiatric settings to fill their SSRI prescriptions only once, Dr. Crystal commented.

Others worry that physicians are not paying enough attention to patient factors that could make initiation of SSRIs dangerous. Dr. Malcolm B. Bowers Jr., a psychiatrist at Yale University in New Haven, told CLINICAL PSYCHIATRY NEWS that SSRI-induced psychosis has accounted for 8% of all general hospital psychiatric admissions over a recent 14-month period.

The pattern suggests that while SSRIs are a help to the majority of patients who take them, more needs to be done to make sure that doctors prescribing the drugs evaluate patients for psychotic predispositions vulnerable to SSRIs. Such patients may include those with a history of psychotic illness or early signs of mania.

"What is surprising is that this particular group of side effects is really underplayed," Dr. Bowers said.

Dr. Malcomb Browers; Yale Study Abstract

The ICFDA has done some research and discovered that in 1994, there were l,908,000 patients admitted to psychiatric hospitals in the United States.

According to this article, 8% were admitted with a diagnosis of SSRI induced psychosis. That means that 152,000 patients had a psychosis in 1994 due to SSRIs. That number is probably low because some people were admitted to a psychiatric hospital with an SSRI induced psychosis and this was not recognized for what it was.