Efficacy of Psych Drugs: Do Antidepressants Work?

A couple of years ago there was a major meta-analysis published in the Journal of the American Medical Association that questioned the efficacy of antidepressants, particularly for people with less severe depression. It stated: “The magnitude of benefit of antidepressant medication compared with placebo increases with severity of depression symptoms and may be minimal or nonexistent, on average, in patients with mild or moderate symptoms.”

The press ran with this statement like wild telling anyone who would listen that “antidepressants don’t work,” although that’s far from what the analysis said. The next sentence in the abstract is, “For patients with very severe depression, the benefit of medications over placebo is substantial,” but I suspect most journalists never bothered to look that up.

Regardless, the question is, do antidepressants work and do they measure up to the efficacy seen in other drugs.

Drug Efficacy

Drug efficacy is rated on a scale where an effect of 0.2 is considered significant but low, and an effect size of 0.8 or above is considered high while the median of all effect sizes is 0.4.
Recently a major meta-analysis  was done comparing the efficacy of psychiatric medication to other types of medication and surprise—psychiatric medication is as efficacious, on average, as other medication used in internal medicine.

Here are a few examples for you:

• Interferon used to treat chronic hepatitis C is high at 2.27
• Statins and aspirin in cardiovascular disease and stroke, had small effect sizes (0.12 for aspirin for secondary prevention of cardiovascular events and 0.15 for statins for cardiovascular events)
• Antidepressants used as maintenance treatment to prevent a relapse of major depression had an effect size of 0.64
• Antipsychotics used to prevent relapse in schizophrenia had an effect size of 0.92
• Atypical antipsychotics and haloperidol used for acute mania had an effect size of 0.44

Importance of Drug Efficacy

Obviously, drugs have to work in order for people to take them and the U.S. Food and Drug Administration ensures that this is the case. But additionally, it’s important that people understand that media reporting of a lesser efficacy of antidepressants in people with less severe depression does not mean that people should throw their drugs out the window and assume they don’t work.

Far from it.

That type of unthinking behavior can result in relapse, hospitalization and even death.

What does matter is that if people want to listen to science then they should fully understand what the science is trying to say—and no science is saying that antidepressants don’t work, but science is trying to identify the patient populations in which antidepressants work best.  And while there are inherent problems in psychiatric drug studies and outcome measurements, it’s critical that people thoroughly think through the issues with their doctors rather than come to snap judgments.

For a greater discussion on the new meta-analysis and some of the issues facing psychiatric drug statistics, please see here.