By now, you’ve likely read a shocking headline questioning the effectiveness of the latest generation of antidepressants. Kirsch et al. report that selective serotonin reuptake inhibitors (SSRIs) are only slightly more effective than placebos at reducing depression in a meta-analysis of US Food and Drug Administration (FDA) data. Are these data really worth all the fuss?
As Nicola Jones points out in the Great Beyond, drug companies are not required to publish negative data. Suspicious that published data on SSRI effectiveness were biased, the authors obtained FDA data via the US Freedom of Information Act. Researchers use the Hamilton Rating Scale of Depression (HRSD) to rate depression severity. Antidepressant treatment should reduce depression scores. Placebos often also reduce HRSD scores. A meta-analysis of FDA data showed that most SSRIs significantly (in the scientific sense) reduced HRSD scores relative to placebo, but the relative reduction was less than the effective criterion established by the UK National Institute for Health and Clinical Excellence (NICE). Thus, by NICE criteria, SSRIs would not benefit most people (Note: I am unaware whether the FDA has a similar effectiveness criterion).
By NICE standards, does anyone benefit from SSRIs? The authors found that people with high HRSD scores (people with severe depression) showed SSRI-induced HRSD reductions that passed by NICE criteria, suggesting that SSRIs effectively combat severe depression. However, placebos were less effective at reducing HRSD scores in people with severe relative to mild depression, which may explain the relative increase in SSRI effectiveness, according to the authors.
I’m not a physician, nor am I a policy maker, so I can’t comment on NICE’s effectiveness criteria. However, based on this study, it is inaccurate scientifically to describe SSRIs as ‘ineffective’. That does not suggest that I have feelings about whether they should or should not be prescribed. Are antidepressants overprescribed? Probably. Should people stop taking their SSRIs. NO! It is never safe to reduce, change or stop antidepressant treatment without the supervision of a physician. Perhaps, in the end, effectiveness is in the eye of the patient and his or her prescribing physician.