Altered placebo and drug labeling changes the outcome of episodic migraine attacks

How much of a treatment's measured effect is attributable to what the patient is told the pill is?

• 66 participants treated multiple episodic migraine attacks each, producing several hundred attacks in total.
• Each attack was treated with an envelope labelled “Maxalt” (rizatriptan), “placebo”, or “Maxalt or placebo” — and the contents did not always match the label.
• Because each participant served as their own control across attacks, drug and label effects could be compared within the same person.

• Pain relief tracked both the pill and the label, and the label accounted for a substantial share of the total measured effect.
• Placebo pills labelled as the active drug outperformed placebo pills labelled as placebo.
• Notably, placebo openly labelled as placebo still outperformed treating the attack with no pill at all.

• Single condition with self-reported pain outcomes.
• Participants were experienced migraine patients who knew the study involved mislabelling, which shapes expectation in its own way.
• The deceptive labelling design is not repeatable in ordinary clinical practice.

It quantified the information component of a treatment separately from its pharmacology — a core reason placebo controls and blinding exist in trial design.