Two-thirds of children and even more adults did not see a doctor or therapist for mental health care once within a month of beginning drug treatment, according to the study by Medco Health Solutions Inc., which manages prescription benefits for health plans.
Experts suggest the cost of therapy, a lack of follow-up by busy family doctors, and a shortage of psychiatrists in some parts of the country might help explain the problem.
Medco's study of 79,488 adults and 5,026 youngsters reviewed prescription and doctor visit records from July 2001 through September 2003. That was before the government urged drug makers to put warnings on their products calling for close monitoring of suicidal thoughts or violent behavior in the early weeks after starting the drugs.
"Many of these people probably should have had more follow-up than they did, regardless of the FDA guidelines," said Dr. Glen Stettin of Franklin Lakes-based Medco, which paid for the study.
In early 2004, the Food and Drug Administration recommended that new antidepressant users see a doctor once a week for the first month and three more times in the following two months.
That advice is the agency's "best estimate" of what's reasonable, said Dr. Thomas Laughren, director of the Division of Psychiatry Products at the FDA.
Laughren said he is concerned that so few people in the study failed to get therapy, but said the sicker patients probably got more help.
The Medco study also looked at treatment through the first three months and found that more than half the children and three-quarters of adults still had not had a mental health visit. Fewer than 15 percent of patients got all the treatment the FDA recommends in the first month, according to the study, which was published in this month's American Journal of Managed Care.
More than half of antidepressant prescriptions are written by family doctors, and there are only about 40,000 psychiatrists nationwide.
That's one reason some experts believe there is little follow-up care. In addition, Dr. Darrel Regier, the American Psychiatric Association's director of research, said that carrying out the FDA treatment recommendations would push up costs up more than 50 percent.
Stettin and other doctors said follow-up therapy has probably improved a bit since Medco's study was done because of heavy press attention, particularly about antidepressants and suicide concerns with teenagers. Medco plans an update to see if that's so.
Meanwhile, the number of children taking antidepressants dropped 18 percent in the first three months of 2004, an earlier study by Medco found.
"That's something a lot of people are concerned about," Laughren said.
That's because for many patients, not treating depression is more dangerous than the slight increased risk of suicidal behavior at the onset of treatment — from 2 percent to 4 percent, according to 24 studies in children reviewed by the FDA.
"Ten percent of patients with severe depression will kill themselves" without treatment, said Dr. Richard A. Friedman, director of the psychopharmacology clinic at Cornell University's medical school.
Overall antidepressant use, which rose about 10 percent a year early in the decade, rose by less than 2 percent last year before picking up slightly this year, according to health information company IMS Health. U.S. sales exceeded $12.5 billion last year.
Besides major depression, drugs such as Prozac, Zoloft, Paxil, Lexapro, Effexor, Celexa and Wellbutrin are prescribed for patients with anxiety and panic disorders, premenstrual syndrome and social phobias.