A randomized controlled trial involving 90 healthy older adults found that placebo pills were associated with measurable improvements in memory, physical performance and stress over a three-week period, including among participants who knew the pills contained no active ingredients. The study, published in the International Journal of Clinical and Health Psychology, was led by Diletta Barbiani, Alessandro Antonietti and Francesco Pagnini of Università Cattolica del Sacro Cuore in Milan.
Researchers divided participants into three groups: one received no treatment, one received inactive pills described as an active supplement intended to improve well-being and physical functioning, and a third received the same pills but was explicitly told they were placebos that might still trigger beneficial mind-body responses. Before and after the trial, participants completed questionnaires on perceived stress, psychological well-being, sleepiness, fatigue, optimism, self-efficacy and views on aging, while also undergoing tests of short-term memory, selective attention and physical performance.
At the end of the study, the group that knowingly took placebo pills reported lower stress than both the deceptive-placebo group and the control group, and also showed significant gains in short-term memory compared with those who received no intervention. Both placebo groups improved on cognitive and physical measures overall. Physical performance rose by 7% in the deceptive-placebo group and 9.2% in the open-label placebo group. On cognitive tests, scores increased by 12.6% to 14.6% among those who believed they were taking a real supplement, while the open-label placebo group improved by 6.9% to 21.5%, depending on the measure. Researchers also reported reduced drowsiness.
The authors said the findings suggest placebo treatments could support several aspects of healthy aging, with open-label placebos performing as well as, and in some measures better than, deceptive placebos. Pagnini argued that the results are consistent with a broader line of research examining how thoughts, emotions and self-perception may affect aging-related outcomes. The researchers further said open-label placebos may offer an ethically acceptable approach because participants are informed the pills are inactive while still potentially benefiting from placebo mechanisms.
No separate critical assessment was presented alongside the study findings in the available material. The report instead emphasized the researchers' view that the results add to evidence of a strong connection between mental processes and physical and cognitive functioning in later life, and that this connection could become a focus of future healthy-aging strategies.