The National Health Service in the United Kingdom spends over 300 million pounds per year on antidepressants (475 million USD).

Yet in a large study comparing antidepressant drugs with placebos, Irving Kirsch found no significant difference between placebos and ‘active’ drugs except for patients with severe depression.

Last Sunday night the research was discussed in a CBS 60 Minutes report. During her interview, reporter Lesley Stahl challenged Kirsch: "You're saying if (patients taking antidepressants) took a sugar pill, they'd have the same effect?"

Kirsch replied: "They'd have almost as large an effect, and whatever difference it would be, would be clinically insignificant."

Stahl was incredulous. "But people are getting better taking antidepressants, I know them. We all know them."

"People get better when they take the drug, but it's not the chemical ingredients of the drugs that are making them better. It's largely the placebo effect," Kirsch replied.

Kirsch’s research raises many provocative questions. If placebos appear to cure depression, is depression a real disease? How can a sugar pill cure depression? If sugar pills work as well as drugs and have fewer side effects, why not use them?

Nobody doubts that depression can be very serious. (And any patient taking or considering antidepressant medication should consult a qualified practitioner before making treatment decisions.) Instead, it means placebos are particularly good at curing depression. This can be achieved through several mechanisms. The sugar in the pill can influence insulin levels and induce a cascade of physiological effects. Moreover the doctor’s friendly manner, also part of the placebo, has been shown to make mildly depressed patients feel better.

The reason placebos aren’t prescribed is doctors deem them to be unethical. This is because (among other reasons) doctors should only prescribe treatments that are proven to be effective. But effectiveness is often established by demonstrating superiority to placebos; so to prove they are effective, then need to be more effective than themselves, which is impossible. Moreover, as Stahl noted, the ‘real’ drugs have known and serious side effects. So not prescribing placebos might be even less ethical.

Whatever the answers to these difficult questions, surely we can come up with an answer to the placebo ethics dilemma that costs less than 300 million pounds per year. More research, please!