Antidepressant Effectiveness Is Negligible in Cases of Mild to Moderate Depression
The true effects of two widely used antidepressant drugs, Paxil and Imipramine, are “nonexistent to negligible among depressed patients with mild, moderate, and even severe baseline symptoms,” according to the findings reported in today’s issue of JAMA, the journal of the American Medical Association. The research is likely to apply to most antidepressants prescribed.
On the other hand, the drugs do work for the most severely depressed patients, the report also shows.
Antidepressant drugs have been available for decades. One of the drugs tested in the new report, imipramine, was developed in the 1950s. So it’s astonishing that the information has just appeared now, and it’s worth taking a closer look.
The authors of the JAMA study explained that most studies of antidepressants are designed to enroll patients with severe depression, those who could show the greatest improvement. But the practice excludes many patients with lower levels of depression, a group which probably comprises the largest portion of patients treated for depression in actual practice.
From thousands of trials of antidepressants, the researchers selected six well-designed studies that nevertheless included patients with lesser levels of depression. They examined the relationship of severity of depression at time of enrollment (assessed according to a widely used method) and the effect of treatment by drug or placebo. They found that the effect of the drug minus that of placebo (i.e., the true pharmacological activity of the drug) decreased with the severity. For patients with less than the most severe level of depression, the drug didn’t work significantly better than the placebo.
Clinical trials of antidepressant drugs suffer from the same fundamental, well-understood flaw of almost all studies testing the effectiveness of new drugs. The studies enroll subjects insufficiently representative of the general patient population and define outcomes inadequately reflective of their illnesses. Despite these deficiencies, once the drugs get approved, marketing by the pharmaceutical companies targets the medicines to the largest patient population groups that can be rationalized.
Medical experts, like Harvard’s Jerry Avorn, have criticized the situation for many years. They’ve made the case that the criteria for new drug approval used by the FDA often allow drugs to the market that may not bring significant improvement for most patients prescribed them. In the context of the spiraling costs of health care, this situation causes financial problems, in addition to clinical ones.
So is going to your doctor for depression like going for an earache? You get a prescription for an antidepressant or antibiotic. But in most cases, neither drug does much good, except that you and your doc get to feel you did something for the problem. And everyone ignores the negative consequences—everyone except the drug companies, for which the consequences are not bad at all.
This entry was posted on Wednesday, January 6th, 2010 at 12:43 pm and is filed under Medicine and Science. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.