The Myth of the Fixed Personality
Evidence from ayahuasca research challenges the idea of a set personality and opens new doors to change
Some people claim that only laboratory studies — those following the gold standard of research aimed at establishing causality, the randomized controlled trial — should be taken seriously when evaluating whether X has an effect on Y. But in real life, one thing is certain: people don’t live in laboratories, and life is a messy web of circumstances and conditions that no one can control.
So why do we still chase the chimera of the randomized controlled trial? Is it because having control reassures our anxious minds that we can, in fact, control and predict something? Because we live in a time and space where the supremacy of the mind — “I think, therefore I am” — defines “understanding” as the ultimate goal of both science and existence itself?
Don’t get me wrong, I have nothing against understanding how things work — after all, that’s how we’ve evolved as the ruling species on this planet. My point is that if we limit ourselves to only considering randomized controlled trials and their results, our ability to grasp the complexity and beauty of life will be severely diminished.
Especially when we’re dealing with situations or substances where finding a suitable placebo is a serious challenge — like when working with psychedelics. Participants will know whether they’ve taken the actual treatment, whatever psychedelic it may be, or just a sugar pill.
A fixed personality?
The long preamble on research standards is meant to open a window into why researchers so often say, “It’s complicated,” and “The results are inconsistent.” Because they are. Between studies, they certainly are. And yes, it is complicated to play detective and figure out what’s going on — what are those differences between the studies that render the results different from study to study.
Lately, I’ve been interested in the effects of psychedelics — especially ayahuasca — on personality traits. I find it fascinating that we tend to believe personality is pretty much fixed, something you’re stuck with once you’ve got it. Once a Scrooge, always a Scrooge.
But more and more, researchers are arguing that certain modalities can have a significant and transformative impact on what we call personality traits — those characteristics often seen as fixed. Meditation is one such modality [1]. Psychedelics are another.
Ayahuasca has the potential to help individuals change something considered quite resistant to change: their personality.
But before getting into the nitty-gritty of the studies linking ayahuasca and personality change, let’s first take a look at how personality is actually measured. Through subjective personality tests — sets of questions designed to tap into the observable manifestations of what scientists believe are unobservable (or latent), independent dimensions. Meaning, a person’s position on one dimension shouldn’t predict their position on another.
Let’s take, for instance, one well-known personality test — the Big Five Inventory. It’s called the Big Five because it’s based on the assumption that we can identify five distinct dimensions of personality. These dimensions don’t exclude each other, and a person can score differently on each of them. The five are:
Extraversion: reflects the degree to which someone is outgoing, energetic, and sociable;
Neuroticism: captures emotional sensitivity and the tendency to experience negative emotions such as anxiety or irritability;
Conscientiousness: describes self-discipline, organization, and goal-directed behavior;
Agreeableness: relates to empathy, cooperation, and interpersonal warmth;
Openness to Experience: refers to intellectual curiosity, imagination, and a preference for novelty and complexity.
But then, to make things more complicated, other scholars propose different models of personality, with varying numbers of dimensions [2]. And others keep refining these scales, adding new dimensions… you get the picture — it’s complicated.
On a side note, it might seem like science is just a bunch of people guessing how to define, categorize, and conceptualize life in a way that simplifies it — without anyone really knowing if what they measure genuinely captures what they intended to measure.
This is to some extent true.
The scientific endeavor — especially in the social sciences — is deeply dependent on how refined (or not) our theoretical and methodological tools are. We start with a general observation, test it against what we observe around us, draw conclusions about the validity of our hypotheses, refine the theory, test it again against the observable, and so on.
We can only know what we know at a particular point in time, so knowledge is always tentative and open to challenge by new empirical evidence.
Hence, “it is complicated” and “we need more research”.
Back to personality and ayahuasca. Why is it important to understand how personality is measured? Because it helps us see that one reason results between studies conflict or point in different directions is that researchers have measured their constructs differently. For example, personality may have been assessed using different methods, or ayahuasca was brewed and served differently.
But then, are these results even comparable? Can we make sense of this conceptual and methodological mess?
My take is to use common sense, a pinch of critical thinking, and try to assess the plausibility of the claim that X (in this case, ayahuasca) causally impacts Y (personality traits).
The study
A recent study supporting this claim [3] was not conducted in a laboratory but was an observational study — meaning it collected data from people who attended a one-week retreat in the Amazon at three healing and spiritual centers serving the brew. So yes, people chose to go there themselves — meaning they represent a selected part of the population, first knowing these centers exist and then being able to afford the trip.
Could this be problematic for the robustness of the results? The shorts answer is yes.
To give an example, let’s imagine that participants at one center systematically differ from those at others. Say all women, highly educated and under 30, go to Center A, while all men, less educated and over 40, go to Center B. Why does this matter? Because research shows socio-economic status is linked to personality traits, meaning individuals with certain personality structures might cluster in the same centers. We also know socio-economic status relates to other factors — like social support, self-efficacy and self-esteem, and emotional or financial resources. The implication of such a hypothetical example would be that any results the authors report could simply reflect differences in these participant characteristics and how they’re distributed across centers.
This isn’t a new problem in social science research, and yes, it gives researchers something extra to consider — how to account for influences that could confound the main relationships they’re trying to study.
One way to address this is by considering as many of these confounding influences as possible — developing theoretical reasons why they might matter, then doing their best to measure and include them in the analysis.
Without going into the details of how this is done, it’s enough to say that in this study the researchers measured and examined the impact of a wide range of variables on the main effects of interest — ranging from participants’ expectations for their retreats, to characteristics of the ceremony, the difficulty of the psychedelic experience, and levels of suggestibility and intensity of the mystical experience.
To strengthen the robustness of the results even further, they also collected data from informants — people close to the participants — about the personality changes observed after returning from the ceremonies.
So, here’s how they collected the information: they initially selected 330 participants, then applied further criteria and excluded those with missing data at one of the three collection points — before the ceremony, after one week, and three months later. The final sample included 256 participants, mainly men (161 to 94), mostly young white adults, with an average age around 35. For 110 of these participants, the researchers also had informant data evaluating their personality before and three months after the ceremony.
Does consuming ayahuasca result in short- and long-term personality changes?
Short answer again — yes. A week after the ceremony, participants reported significantly lower scores in Neuroticism, and significantly higher scores in Openness, Extraversion, Agreeableness, and Conscientiousness.
How about after three months? Scores on Neuroticism remained lower than before the ceremony, while Openness, Extraversion, and Agreeableness stayed significantly higher.
And what about the informants’ reports? For that subsample, informants corroborated these findings, reporting that their close ones showed significantly lower levels of Neuroticism and significantly higher levels of Openness.
While these results are interesting — and certainly seem quite robust for the dimension of Neuroticism — the question remains: how strong are they? The authors made an interesting comparison, looking at the strength of the effects found in their study against a summary measure based on studies examining the impact of clinical interventions (such as different types of therapy) on personality. Here’s what they say:
“By comparison, self-reported change in Neuroticism following an average of 1.4 weeks at the retreat center and 4.4 ayahuasca ceremonies was associated with an effect comparable to the average effect of multiple weeks of clinical intervention.” (pg.6653)
How amazing is this conclusion? After just a week and between four to five ayahuasca ceremonies, the change in one personality dimension — Neuroticism, which is strongly linked to psychopathology like mood disorders, anxiety, and addiction — shows a decrease comparable to that seen after several weeks of therapy.
Now, before you think I’m suggesting everyone should enroll in an ayahuasca retreat instead of seeing a psychologist — which is definitely not my intention, as working with psychedelics isn’t for everyone — these results are promising. They suggest that ayahuasca has the potential to help individuals change something considered quite resistant to change: their personality.
What I find intriguing — and this comes through in other studies examining ritualistic, ceremonial use of ayahuasca in naturalistic settings [4] — that is, outside the laboratory —is that the ceremonies are not embedded in formal integration processes to apply any insights gained in daily life. In other words, there’s no follow-up, no coaching, no therapeutic sessions. And yet, these naturalistic studies still point to changes in personality traits — especially Neuroticism — after participating in ayahuasca ceremonies, even when taken deep in the jungle, away from Western ceremonial spaces or therapeutic medical settings. This also stands in sharp contrast to results from randomized controlled trials, where such changes are not consistently found [5].
So what’s happening here? This particular study highlights several aspects of the ceremony that seem especially relevant to the personality changes observed — the perception of the shaman as trustworthy, the music, the sacramental atmosphere, the communal or group setting, and even the purgative elements. Take the group context, for example: it’s possible that sharing such a powerful experience with others fosters empathy, trust, and a sense of connection. Moments of insight like “I’m not alone with this or in this” may arise, alongside opportunities to practice new behavioral patterns and ways of relating to others.
We are now on the realm of speculation, but these elements of the ceremony are in sharp contrast with how a random control trial would look like. And on the other hand, they are more in line with the newly developed psychedelic assisted therapy protocols that emphasize the important role that such ceremony-related elements can have.
Still, whether or not we’re eager to label these results as evidence of genuine causal effects, or driven by a desire to understand what’s happening and why — even setting aside the financial argument tied to their potential efficacy — what I see in this article is hope. Hope that we can begin to expand the repertoire of what we consider legitimate well-being or mental health care, and hope for a more holistic approach to alleviating unnecessary suffering.
References
[1] Goleman, D., & Davidson, R. J. (2017). Altered traits: Science reveals how meditation changes your mind, brain, and body. Avery.
[2] Tellegen, A., & Waller, N. G. (2008). Exploring personality through test construction: Development of the Multidimensional Personality Questionnaire. In G. J. Boyle, G. Matthews, & D. H. Saklofske (Eds.), Personality theory and assessment (pp. 261–291). Los Angeles, CA: Sage.
[3] Weiss, B., Miller, J.D., Carter, N.T., & Keith Campbell, W. (2021). Examining changes in personality following shamanic ceremonial use of ayahuasca. Scientific Reports, 11, 6653.
[4] Perkins, D., Pagni, B.A., Sarris, J., Barbosa, P.C.R., & Chenhall, R. (2022). Changes in mental health, wellbeing and personality following ayahuasca consumption: Results of a naturalistic longitudinal study. Frontiers in Pharmacology, Volume 13–2022.
[5] Mendes Rocha, J., Rossi, G.N., Osório, F.L., Bouso Saiz, J.C., Silveira, G.O., Yonamine, M., et al. (2021). Effects of Ayahuasca on Personality: Results of Two Randomized, Placebo-Controlled Trials in Healthy Volunteers. Front Psychiatry, 12, 688439.
This article was first published here.
