Trial Report Placebo mechanisms in aging: A randomized controlled trial comparing deceptive and open-label placebos on ... functioning, 2026, Barbiani et al

[rvallee]

Placebo mechanisms in aging: A randomized controlled trial comparing deceptive and open-label placebos on psychological, cognitive, and physical functioning in older adults

https://www.sciencedirect.com/science/article/pii/S1697260026000104

Abstract​

Objective​

No study has yet examined whether a placebo in its traditional meaning—an inert treatment presented as active—can influence functions that tend to naturally decline with age. We aimed to clarify whether a deceptive and open-label placebo procedure would affect psychological, cognitive, and physical functioning in community-dwelling older adults.

Methods​

Ninety healthy older adults were randomly assigned to one of three conditions: a control group receiving no intervention; a deceptive placebo group receiving placebo pills along with information that these contained active ingredients known to improve functioning and well-being; an open-label placebo group, explicitly informed that the pills were inert but capable of eliciting beneficial mind–body responses. Participants completed self-report measures (perceived stress, psychological well-being, sleepiness, fatigue, optimism, self-efficacy, aging stereotypes) and objective tests of short-term memory, selective attention, and physical performance before and after the 3-week intervention.

Results​

After 3 weeks, the open-label placebo group exhibited lower perceived stress compared with both the deceptive placebo and control groups. Short-term memory performance also significantly improved in the open-label placebo group relative to controls. Within-group analyses revealed consistent cognitive and physical improvements in both placebo groups, with particularly pronounced effects in the open-label placebo group.

Conclusions​

Placebo interventions enhanced multiple domains of functioning in older adults, with open-label placebos producing benefits comparable to or greater than deceptive placebos. These findings suggest the potential of open-label placebos as a promising, ethically acceptable approach for supporting healthy aging.

 

[rvallee]

Here we see the logical conclusion of psychobehavioral woo and the dysfunctional application of so-called evidence-based medicine, where 0=0 means that it works. 'Honest' placebo and 'deceitful' placebo 'perform' the same, therefore they are both not just effective, but almost miraculously so. They really think they have found the "one simple trick" that just solves complex problems which no one has ever thought of before.

This is completely brain dead. The health benefits of supplements have been studied for decades and have been almost universally found to be worthless. This is the exact same approach, but because the experts involved believe in the placebo they proclaim an effect that they would universally dismiss to be found with supplements, even though the approach to testing is exactly the same.

The most useful data, yet again, is simply that the way health is assessed is flimsy and unreliable. There is no metric of good health, only ratings and scores, and those are heavily influenced by all sorts of things. And as usual a lot of weight is put on the idea that perception has changed, rather than its reporting, as if the idea that people will report things differently than how they are feeling for all sorts of reasons is unthinkable, let alone common.

This woo nonsense remains the last major scientific frontier for humanity to clear. It's pure magical thinking that is taken seriously, might as well be the application of astrology to medicine, and somehow even though the people who believe in it keep proving it wrong, they still hold on to those beliefs because those beliefs are just that popular and they can't let go of them.

Popular wins over correct every single time. Even among experts. Even in medicine. Even among experts in medicine discussing health. Belief is that powerful in social affairs, just not in the way it's been claimed to. It doesn't affect health, but is sure affects health policy.

 

[Jonathan Edwards]

Within-group analyses revealed consistent cognitive and physical improvements in both placebo groups, with particularly pronounced effects in the open-label placebo group.

It is bizarre that people who claim to have expertise in psychology have no insight into the spsychology of this. Of course the open placebo will do well, because that was the point of the trial - to show that open placebos do well, and subjects don't like to disappoint their nice psychologist researchers. The deception is just on the other foot.

 

[Utsikt]

They used the digit span test and the short stroop task to measure cognition. Both tests are quite unreliable and likely to be influenced by the same mechanisms that creates bias in the self-report outcomes.

The short physical performance battery, measuring balance, gait-speed and lower-limb strength is more reliable. Unsurprisingly, they found no between group differences on these scores.

The open-label doing better than deception can easily be explained by the difference in the instructions:

Spoiler: Spoiler

Deceptive placebo (DP)​

Participants in the deceptive placebo group received 21 tablets described as multivitamin supplements purported to enhance functioning and overall quality of life in adults over the age of 65. The manipulation, which involved the use of deception, was accompanied by the following standardized script:

“This is a multivitamin supplement containing a complex of vitamins designed specifically for adults over the age of 65. Benefits typically observed within the first week include enhanced cognitive abilities—such as concentration and memory—greater physical energy, and reduced fatigue. In addition, this supplement is expected to improve mood, reduce stress, and promote overall well-being, helping to counter age-related declines in functioning. Beginning today, we ask you to take one tablet per day for three weeks. After this period, we will invite you to return to the same location to repeat some tests and complete the study.”

Open-Label placebo group (OLP)​

Participants in the open-label placebo group were given the same 21 tablets as the deceptive placebo group. However, unlike the DP group, the tablets were explicitly described as placebos – substances devoid of specific therapeutic properties that could nonetheless produce beneficial effects through a real and tangible mind-body phenomenon (i.e., the placebo effect). In this condition, no deception was employed. The procedure was accompanied by the following standardized explanation:

“We would like to inform you that these tablets have no specific therapeutic properties. They are simply sugar pills that can be safely taken by anyone. The purpose of our research is to investigate the placebo effect, a well-established psychobiological phenomenon demonstrating how the mind can influence the body. In particular, when individuals hold expectations about the efficacy of a treatment, these expectations alone can lead to genuine improvements.

Given this, we ask you to take these placebo pills in an ‘open-label’ fashion—that is, knowing that they contain no active ingredients but keeping in mind the body’s natural ability to self-heal. When taking the pills, we ask you to consider the following points:

• (1)
  The placebo effect is a powerful and pervasive phenomenon that activates specific brain regions associated with real therapeutic changes;
• (2)
  The body’s response to placebo can occur automatically, much like Pavlov’s dogs salivating when they heard the bell;
• (3)
  A positive attitude may enhance the effect but is not strictly necessary;
• (4)
  Adhering to the treatment schedule is essential.
  

  In light of this information, we now ask you to take these tablets with awareness of their potential to enhance your cognitive and physical abilities and to reduce your stress levels. Starting today, please take one tablet per day for three weeks. At the end of this period, we will invite you to return to this same location to repeat some tests and complete the study.”

Of note, when introducing the example of Pavlovian conditioning, participants were first asked whether they were familiar with the concept. If they indicated familiarity, the experimenter proceeded with the standardized rationale. If not, a brief explanation of Pavlovian conditioning was provided before continuing, as follows:

“For example, in classical conditioning studies, Pavlov showed that dogs could learn to associate a neutral stimulus, such as a bell, with food. After repeated pairings, the dogs began to salivate when hearing the bell alone, demonstrating how learned expectations can produce automatic physiological responses.”

The open label placebo is in reality much more deceptive and intensive than the deceptive placebo. But the authors have the gall to argue that it’s actually very ethical:

Despite these limitations, the study offers several important implications. The observed efficacy of OLPs suggests their potential as ethical, non-pharmacological interventions to reduce stress, and foster cognitive and physical functioning in older adults.

Although placebo effects have traditionally been linked to deception, our findings add to the growing evidence that open-label placebos—when accompanied by a credible mind–body rationale—can be equally or even more effective than deceptive placebos.

This approach aligns with principles of autonomy and transparency and represents a low-cost, scalable strategy that can be integrated into cognitive training, physical rehabilitation, or outpatient and community-based programs without ethical concerns or adverse effects (Blease et al., 2016).

And apparently, they believe there exists a way to blind an open-label placebo:

Finally, future studies could incorporate active control conditions (e.g., attention-matched interventions) to better isolate placebo-specific effects, monitoring, and standardized assessments of treatment credibility and blinding to strengthen causal interpretation.

Lastly, there’s this gem at the end of the limitations:

Finally, the study was not preregistered, which represents an additional limitation given the number of outcomes examined and the exploratory nature of some analyses. Future research would benefit from preregistered designs and larger samples to improve inferential strength and reproducibility.

 

[rvallee]

Absolutely right @Utsikt, the 'honest' arm is actually far more deceitful than the 'dishonest'. It sure is to me:

• (1) The placebo effect is a powerful and pervasive phenomenon that activates specific brain regions associated with real therapeutic changes;
• (2) The body’s response to placebo can occur automatically, much like Pavlov’s dogs salivating when they heard the bell;
• (3) A positive attitude may enhance the effect but is not strictly necessary;
• (4) Adhering to the treatment schedule is essential.

This is very deceitful, none of this is true. It is more 'open', but it's also even more deceitful than "those are multivitamins developed specifically to provide benefits in what we will be assessing".

Although placebo effects have traditionally been linked to deception, our findings add to the growing evidence that open-label placebos—when accompanied by a credible mind–body rationale—can be equally or even more effective than deceptive placebos.

They promised something that works even though it doesn't and they think it's not deceptive? The whole thing, zooming back out for a broad overview, is just the application of "the ends justify the means", which completely overlooks that almost always the means actually become the ends, and by being OK with deceit all they do is build a system on deceit, where deceit is actually honest and good. And by god they did it. They built the ultimate deception machine, one in which the people most deceived are the ones doing the deceit. A system in which everyone lies, and some lies are more true than others.

This approach aligns with principles of autonomy and transparency and represents a low-cost, scalable strategy that can be integrated into cognitive training, physical rehabilitation, or outpatient and community-based programs without ethical concerns or adverse effects

"Lies are actually truth, Winston". Orwell would probably feel like slapping these people.

How the hell is Pavlov's nonsense still taken seriously? Dogs are smart, they are able to notice patterns, and this 'response' is a display of intelligence, not some mindless conditioning. What century is this even?