A Review of The Emperor’s New Drugs: Exploding the Antidepressant Myth by Irving Kirsch
Are anti-depressants really just expensive placebo pills? In a searing review of clinical studies involving anti-depressants, psychologist Irving Kirsch raises significant doubts about the efficacy of drug treatments for depression. Kirsch describes his initial assumption that anti-depressants worked. He had witnessed clients who took anti-depressants and had improved. In researching placebo effects in depression treatment, however, Kirsch opened a Pandora’s Box that is reverberating throughout the mental health field.
Kirsch’s primary expertise is in placebo effects. He began his analysis by issuing a Freedom of Information Act request to the FDA for all clinical trials involving anti-depressants and depression. Kirsch notes that 40% of clinical trials were withheld from publication – primarily because the studies did not find significant improvement for their participants.
The results of Kirsch’s FDA data analysis are startling. Groups that had received anti-depressants or placebos both showed nearly equal improvement. While the drug group improved at a slightly higher rate than the placebo group, the results were not clinically significant. The vast majority of response to anti-depressants turns out to be a placebo effect from having received a pill. Kirsch concludes that 82% of the response to anti-depressants is mere placebo effect.
Kirsch finds the slight difference between placebo and pill can be further minimized by additional investigation. Improvement turns out to be highly correlated with side effects experienced so the greater the side effects the treatment causes, the greater the perceived improvement. This correlation is likely because side effects are associated with the perception a drug is working. A process called “breaking blind” – as in the study is no longer double-blind – means that the group receiving the active treatment knows that it’s not receiving a placebo due to noticeable side effects.
Patients are regularly able to predict whether they are in an experimental group or a placebo group. In one study, 89% of the participants correctly predicted they were in the group given an anti-depressant. Thus, the placebo effect of the experimental group is enhanced (Kirsch calls this an “extra-strength” placebo effect), accounting for the small difference between drug and placebo outcomes.
Given the significant impact of placebo effects on anti-depressants, Kirsch concludes “once you adjust for drug-placebo differences in side effects, difference in rates of improvement are no longer statistically significant.”
Applied to long-term care, Kirsch’s conclusion could not be more timely. A study just released in the British Medical Journal The Lancet found anti-depressants no better than placebos in treating depression associated with dementia. Given the side effects associated with the pills, the authors recommended that anti-depressants not be used as a first-line treatment of dementia-related depression.
As anti-depressants have proven ineffective at alleviating depression when measured against placebos, Kirsch takes aim at the “chemical imbalance” theory of depression. Alleged evidence of a correlation between low levels of serotonin (a neuro-transmitter loosely associated with feeling good) in the brain has been discredited. In fact, a study on reserpine (which actually reduces the amount of serotonin in the brain) found it as effective as drugs that increased serotonin, likely from the placebo effect.
Kirsch ends his book by exploring non-pharmacological interventions in treating depression, most notably psychotherapy and regular exercise. Kirsch sounds a clarion call in support of CANHR’s “least medicating” approach: a culture of care is key to improving clinical outcomes, exercise and activity helps, and avoid drugs unless they are an absolute last resort. In the meantime, sugar pills may do the trick!