Key Insights

• Personality entails the characteristics of patterns, thoughts, feelings and behaviours that make a person unique. While personality traits are fairly stable, they can evolve in response to major life events.
• Psychedelics and personality traits influence each other. Psychedelic experiences can increase traits like openness to experience and extraversion, while pre-existing traits shape how individuals respond to psychedelics. Personalised approaches in therapy may be essential for optimising outcomes.
• Psychedelic research is a relatively new and evolving field. More research is needed to fully understand these substances’ long-term effects, safety profiles, and potential therapeutic applications across diverse populations.

Author: Dilara Oexemann. Dilara holds a master’s degree in clinical psychology and wrote her thesis on the effect of personality traits on the relationship between dose, psychedelic-induced emotional breakthroughs and positive psychedelic effects. In her research, she aims to understand how individual differences shape psychedelic experiences, aiming to contribute to the safe and effective use of psychedelics to transform mental health treatment and enhance personal growth.

Research into the therapeutic potential of psychedelic drugs, both for recreational and clinical use, is undergoing a significant revival. While emerging studies suggest their safety and efficacy, a pressing need remains for more comprehensive research to develop safe guidelines and effective therapeutic protocols. 

Here, we explore the relationship between psychedelics and personality. Psychedelics have been shown to positively influence personality traits, while pre-existing personality structures influence the outcomes of psychedelic experiences. 

Due to their psychoactive properties, the effects of psychedelics are less predictable compared to traditional medical interventions. This unpredictability emphasises the need for research to identify factors – such as personality – that influence these varied outcomes and to ensure the safe and effective application of psychedelics in mental health treatment.

What is personality?

Definition

Personality refers to an individual’s core traits and behaviours that are relatively stable over time and uniquely define how they interact with the world around them. The major traits commonly referred to are the Big Five, or OCEAN: Openness to experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism. These dimensions capture the broad spectrum of human personality and provide a framework for understanding individual differences.

Personality further encompasses an individual’s drives, values, self-concept, abilities, and emotional patterns, which collectively influence how they perceive and respond to their environment. While these traits are generally consistent, personality is not entirely fixed. It can evolve in response to significant life experiences, such as trauma, relationships, or major life changes and events. 

One significant life experience that has been suggested to impact personality is the acute or long-term use of psychedelics. These experiences can profoundly alter perceptions and emotional responses, potentially leading to shifts in core traits or transforming how an individual engages with the world.

Personality Measurement

There is no universally accepted method for assessing personality, but several well-known and widely used tools have been developed over the years.

The Big Five Inventory (BFI) and the Revised NEO Personality Inventory (NEO-PI-R) are the most well-known [1,2]. Both of these tools are based on the traits of the Big Five model discussed above. Each trait exists on a spectrum, ranging from a strong expression to a minimal or subdued presence.

Another approach to personality assessment adds an additional dimension of Honesty-Humility, leading to the development of the Revised HEXACO Personality Inventory (HEXACO-PI-R) [3]. This model expands on the Big Five by incorporating a sixth factor, providing a broader understanding of personality.

The Myers-Briggs Type Indicator (MBTI) is one of the most widely recognized personality tests, known for categorising individuals into 16 distinct personality types. Unlike the Big Five system, which focuses on describing personality traits, the MBTI aims to explain strengths and blind spots of one’s personality through these type classifications. However, despite its popularity, especially in professional settings to assess leadership types, the MBTI has been criticised for its lack of reliability and validity.

The OCEAN or HEXACO model offers a significant advantage over the MBTI in how it measures personality traits. Unlike the MBTI, which categorises individuals into distinct types (e.g., you are either introverted or extroverted), the OCEAN model views personality traits on a continuum. This spectrum-based approach is often considered more reflective of the complexities of human personality, capturing the nuances that exist between extremes.

To achieve a more accurate assessment of an individual’s personality, combining observer ratings with self-reports is beneficial. Self-reports, while valuable, are often subject to biases such as social desirability or a lack of self-awareness. Observer ratings are provided by people who know the individual well, which offers an external perspective that can help balance these biases and provide a more holistic and reliable view of the person’s personality.

In addition to these trait-based models, there are also scales with a neuroscientific basis. The Affective Neuroscience Personality Scales (ANPS) assess personality through the lens of seven primary emotional systems: Seeking, Anger, Fear, Care, Lust, Panic/Grief, and Play [4]. This approach integrates neuroscientific insights into the understanding of personality, offering a different perspective on how traits are expressed and experienced.

Personality’s Influence on Well-Being

Previous research has consistently shown that personality plays a significant role in both mental and physical well-being. Aghababaei & Arji (2014) explored personality and well-being through the HEXACO model and found that extraversion emerged as the strongest predictor of subjective well-being, indicating that individuals who are more sociable, energetic, and outgoing tend to experience higher levels of happiness and life satisfaction [5]. 

On the other hand, the trait of honesty-humility was identified as the strongest predictor of psychological well-being, suggesting that individuals who are sincere, fair, and modest are more likely to experience inner peace and emotional stability. 

Higher neuroticism, characterised by tendencies toward anxiety, moodiness, and emotional instability, has consistently been linked to lower well-being and negative physical health outcomes [6,7].

Psychedelics and Personality

The relationship between psychedelics and personality is assumed to be bidirectional. The existing literature suggests that acute and long-term psychedelic use has a positive influence on personality structure by increasing traits like openness and extraversion and decreasing neuroticism. Here, the psychedelic intake is assumed to have an effect on personality through the therapeutic effect of psychedelics (Figure 1). However, pre-existing personality traits could also influence the psychedelic experience and long-term effects. The model assumes that personality may change the relationship between psychedelic intake and the therapeutic psychedelic effect (Figure 2). 

Research has demonstrated that psychedelics can significantly influence various dimensions of personality. Given that personality encompasses a broad spectrum of traits, ongoing studies are delving deeper into how different psychedelics affect these distinct aspects. In trials investigating the efficacy of psychedelic-assisted therapy for mental disorders, assessing the impact of psychedelics on personality has become a common secondary measure. 

Different neurological theories exist that aim to describe the psychedelic effect. One theory suggests that psychedelics influence personality by promoting neuroplasticity, which involves the formation of new neural connections and the rewiring of neuronal networks (Cameron et al., 2023). Neuroplasticity may underlie the observed personality changes. 

A comprehensive review by Bouso et al. (2018) found that the acute and long-term use of classical psychedelics like psilocybin and LSD can lead to personality shifts by modulating serotonin receptors, a key component of the receptor family.

Another theory suggests that psychedelics induce personality changes by disrupting the Default Mode Network (DMN), which is involved in self-referencing, mind wandering, and autobiographical memory. This disruption reduces rigid, self-centred thinking by altering DMN connectivity and increasing communication between other brain networks. The resulting cognitive flexibility can lead to lasting personality changes, such as reduced neuroticism and increased openness. However, the precise role of DMN modulation in the therapeutic effects of psychedelics requires further research (Gattuso et al., 2023).

Psilocybin: Previous research on Big Five personality changes following psilocybin-assisted therapy for severe, unipolar, treatment-resistant depression found that neuroticism significantly decreased while extraversion increased in participants three months after the therapy compared to baseline (Erritzoe et al., 2018). Both these changes were predicted by the degree of insightfulness experienced during the therapy. Additionally, openness scores showed significant increases, and conscientiousness demonstrated trend-level increases. No significant changes were observed in agreeableness.

LSD: A follow-up study (Holze et al., 2024) on LSD-assisted therapy for anxiety highlights its long-term impact on personality traits, revealing significant decreases in neuroticism and increases in extraversion among participants up to nearly two years after treatment. The participants attributed the positive changes in feelings of depression and anxiety, as well as favourable personality changes to the psychedelic experience.

Ayahuasca: Perkins et al. (2022) found that facilitated ayahuasca consumption in naïve participants led to significant personality changes, including increased extraversion, agreeableness, openness, and authentic living, as well as decreased impulsivity and self-alienation. These changes were associated with improvements in mental health, such as reduced depression, anxiety, and stress, and lower alcohol and cannabis use.

MDMA: In a randomised trial with chronic, treatment-resistant PTSD patients, results showed that heightened openness, but not reduced neuroticism, moderated the relationship between MDMA treatment and symptom improvement. These findings imply that MDMA’s therapeutic effects may extend beyond symptom relief and might have the potential to alter personality structure in a way that supports long-term psychological change (Wagner et al., 2017).

Microdosing, the practice of regularly using low doses of psychedelics, may also have the ability to lead to changes in otherwise stable personality traits. In a prospective survey study by Dressler et al. (2021), most participants microdosed using either psilocybin or LSD. After one month of microdosing, researchers found increases in conscientiousness and decreases in neuroticism, while agreeableness, openness, and extraversion remained unaffected. Additionally, extraversion was positively correlated with participants’ number of lifetime doses and the duration of prior microdosing sessions. In contrast, neuroticism was negatively correlated with the length of prior microdosing sessions.

These studies demonstrate a consistent impact of psychedelics on personality structure across various types of psychedelic substances and different methods of administration. Notably, almost all substances tend to increase openness to experience while reducing neuroticism. However, the effects on traits like extraversion, agreeableness, and conscientiousness remain inconclusive and more research is needed to establish these relationships confidently.

Influence of Personality on Psychedelic Effect and Outcome

Referring to recreational psychedelic use, it’s suggested that individuals inhabiting certain personality traits such as openness, may be more likely to engage in psychedelic experiences. Weiss et al. (2023) found that psychedelic users are more open, extraverted, and less neurotic compared to non-users, suggesting that personality traits may predispose individuals to psychedelic use.

A recent comparative study by Sjöstrom et al. (2024) found that psychedelic users are less depressed compared to non-users. They suggest that personality traits, such as openness and neuroticism, help explain this relationship. These findings highlight the complex role that personality traits play in shaping the effects of psychedelic experiences.

Openness to Experience: This personality trait has previously been associated with positive well-being outcomes both shortly after the psychedelic experience and at follow-up (Haijen et al., 2018). A meta-analysis by Aday et al. (2021) suggests that higher openness significantly predicts decreased adverse effects and the occurrence of mystical experiences (ME), often described as a profound, altered state of consciousness characterised by a sense of unity, transcendence of time and space, deep emotional intensity, and a feeling of connection to a greater reality or divine presence (Mosurinjohn et al., 2023). Often, these experiences lead to more profound and meaningful outcomes. 

Extraversion: In contrast, high extraversion may predict a lower occurrence of ME (Studerus et al., 2012). Several studies assume that this finding may be due to certain traits that people high on extraversion exhibit. For example, individuals in this category may tend to be more talkative or take psychedelics in uncontrolled social settings, which could interfere with the occurrence of these meaningful psychedelic experiences (Johnstad, 2021; Russ et al., 2019).

Neuroticism: Neuroticism can have a negative impact on the psychedelic experience, particularly in uncontrolled settings, where this trait may contribute to more challenging experiences (Barrett et al., 2017). However, individuals with higher neuroticism scores may also have an increased likelihood of experiencing positive mood changes following a psychedelic experience (Mason et al., 2020). The study by Perkins et al. (2022) on ayahuasca’s effect on personality found that traits like high negative emotionality and low self-efficacy, existing before the psychedelic session, were strong predictors of positive outcomes. Further research is needed to explore this relationship. 

Agreeableness: Several studies found that agreeableness does not seem to significantly influence the psychedelic experience or its outcomes (Carhart-Harris et al., 2016; Netzband et al., 2020; Weiss et al., 2021)

Conscientiousness: Current research does not suggest strong associations between this personality trait and psychedelic outcomes (Johnstad, 2021). Similar to extraversion, conscientiousness might affect the acute psychedelic experience indirectly through behaviours typical to this trait – such as preparation and planning – rather than through a direct effect of personality.

The impact of personality on psychedelic effects is less studied than the effects of psychedelics on personality, but it is crucial for ensuring safe and effective use. Understanding how personality traits influence psychedelic experiences could lead to personalised guidelines that optimise outcomes in both therapeutic and recreational settings. Current research is mostly survey-based, and more experimental studies are needed to establish causality.

Personality and Psychedelics Beyond the Big Five

Considering other human traits that share similarities with personality traits in psychedelic research offers a more comprehensive understanding of how these substances impact the whole person and can lead to more personalised and effective therapeutic approaches. It also highlights the interconnectedness of traits and expands potential applications of psychedelics in mental health and personal development. 

One such example is nature relatedness (NR), understood as the subjective sense of connection people have with the natural environment. Like a personality trait, NR can be considered a relatively stable individual characteristic and an integral part of one’s self-concept. Previous research showed a positive correlation between the frequency of lifetime psychedelic use with NR. NR was increased 2 weeks, 4 weeks, and 2 years after psychedelic exposure compared to baseline (Kettner et al., 2019).

Another trait influenced by psychedelics is political ideology. Research suggests that psychedelics can predict an increase in liberal political views. An important factor influencing this change may be the experience of ego dissolution (Nour et al., 2017), a conscious state characterised by a diminished or complete loss of one’s sense of self and a lack of first-person perspective. However, later research suggests that set and setting are the most influential factors in shaping changes in political views. The psychedelic experience alone does not necessarily lead to shifts exclusively in a liberal direction (Pace & Devenot, 2021).

Adding on to this, Lebedev et al. (2023) explored the potential shift in beliefs among psychedelic drug users, finding a moderate positive association between psychedelic use and the acceptance of alternative facts, including the belief that facts are politically influenced. While no connection was found between psychedelic use and a preference for intuition over evidence, the results suggest that psychedelics may promote non-conformist thinking, possibly due to a pre-existing inclination towards unconventional beliefs among users.

Importance of Set and Setting

Personality can significantly influence the set of a psychedelic experience, which refers to the individual’s mindset and emotional state going into the experience. A study by Borkel et al. (2024) found that set is a strong predictor of psychedelic outcomes. For individuals scoring high in neuroticism, the setting, or the environment in which the experience takes place, may be particularly important (Barrett et al., 2017). A supportive and controlled setting can help mitigate potential challenges for those with higher neuroticism. A controlled environment was further found to be beneficial to increase openness and self-transcendence (Bouso et al., 2018).

Borkel et al. (2024) found that positive outcomes, such as lower psychopathology, greater well-being, and enhanced meaningfulness of the experience, were strongly associated with growth-oriented motivations (set), natural environments (setting), and the presence of significant others (set and setting). Conversely, problematic motivations were linked to higher psychopathology and lower well-being, without contributing to a meaningful psychedelic experience. 

These findings suggest that careful attention to factors like set, setting, personality and their interaction is important in shaping the therapeutic potential and may improve outcomes in psychedelic therapy.

Importance for Clinical Practice

The relationship between well-being and personality is well-documented. Psychedelics seem to influence personality changes, such as increased extraversion and openness and decreased neuroticism, that correlate positively with improved well-being. However, as this relationship can work in both directions, increased caution in psychedelic use might be necessary for individuals scoring high on traits such as neuroticism. Further research needs to establish how the psychedelic experience can best be tailored to people scoring high on this trait. 

A recent study by Marrocu et al. (2024) advised special consideration of individuals suffering from a personality disorder due to the potential for more complex and unpredictable outcomes in these populations. More research could establish why this is true for this population and if there are safe and beneficial ways for them to still participate in psychedelic-assisted therapy (PAT). 

The finding that neuroticism can predict challenging psychedelic experiences highlights the significance of individual differences in shaping outcomes. Additionally, the potential for preexisting personality disorders to cause long-term negative effects after psychedelic use further emphasises the importance of considering personality traits.

A study comparing PAT with traditional escitalopram therapy (ET) found both effective for treating depression, with notable changes in traits like neuroticism, introversion, and openness (Weiss et al., 2023). PAT may uniquely enhance absorption – a trait related to openness and deep cognitive engagement – potentially promoting cognitive flexibility and creative problem-solving. These findings underscore the need to consider personality changes in psychedelic research and clinical practice. Further studies are needed to establish PAT’s advantages over ET and optimise its use for different patients.

Ethical Considerations

Psychedelic use is still viewed with caution and raises ethical concerns. Due to the new and evolving nature of psychedelic research and legal constraints that persist in many countries, many recent studies have relied mainly on surveys and the participation of healthy users. Despite their promising results, more experimental studies are currently needed to truly establish the efficacy and safety of psychedelics for both recreational and clinical use. 

To ensure the safety of personality and psychedelic research, ethical considerations are crucial. Informed consent is essential, which means that participants need to be fully aware of potential risks and benefits. Proper screening and support should be provided, especially for those with pre-existing mental health conditions or problematic personality traits. Cultural sensitivity and data privacy are crucial to respect participants’ backgrounds and protect their personal information. Finally, researchers should consider the long-term impact on personality and potentially provide follow-up support. 

Future Directions

As psychedelic research is still in its early stages, long-term changes in personality from both clinical and recreational use remain to be fully understood. To achieve a better understanding of long-term personality changes, follow-up studies should be conducted, where participants are invited to reassess whether the effects of the treatment persist over time. Further, implementing longitudinal studies can help researchers detect developments or changes in the characteristics of the treatment population at both the group and the individual level.

Generalizability is a challenge in psychedelic research due to volunteer bias. Survey studies only include those with prior psychedelic experience, and experimental studies have to select participants who are open to using psychedelics, leading to a sample that may inhibit similar personality traits. To improve the validity of future research, more experimental research, including placebo-controlled and double-blind studies are needed. Further, a stratified sampling method could ensure a more diverse sample.

To tailor psychedelic interventions to individual needs, more research is needed to explore the role of set and setting in relation to different personality traits. Future experiments could compare participants in various settings – such as neutral, natural, or clinical environments – and evaluate their psychedelic outcomes based on personality traits and set – their motivation to take psychedelics – assessed before the experiment.

Lastly, future research may assess whether the occurrence of mystical experiences, emotional breakthroughs, challenging experiences, or self-transcendence intensifies or alters the relationship between psychedelics and personality. Researchers could design studies that assess these experiences alongside personality changes to determine their role in shaping the overall effects of psychedelics.

Final Thoughts

The intersection of psychedelics and personality represents a promising and complex area of research, with the potential to impact therapeutic practices and personal growth significantly. While current studies have highlighted the profound effects psychedelics can have on personality traits, there remains much to explore, particularly in understanding the bidirectional relationship between these substances and individual differences. 

As research progresses, it will be crucial to maintain high ethical standards, especially if some individuals have a higher chance of experiencing adverse effects. The interactions of set, setting, and personality traits on psychedelic experiences should be considered. This evolving field holds the potential to not only deepen our understanding of personality but also to revolutionise mental health treatments.

One crucial factor to consider in psychedelic research is the potential for bias, as it would be unethical to involve participants who are not open to taking these substances. This presents a challenge, especially in personality studies, because an individual’s willingness or prior experience with psychedelics can significantly influence both their personality traits and their response to these substances. This is particularly important when developing mental health treatments, as psychedelics are unique in their strong dependence on set and setting. 

Recognising that psychedelic effects are not uniform to everyone and highlighting the need for careful consideration of individual differences in therapeutic applications might become more important in future psychedelic research.

External references for Personality and Psychedelics

All resources available on Blossom are directly linked on this topic page. Find even more background about this topic with these external references.

1. John, O. P., Donahue, E. M., & Kentle, R. L. (1991). Big Five Inventory (BFI) [Databaserecord]. APA PsycTests. https://doi.org/10.1037/t07550-000

2. Costa, P. T., Jr., & McCrae, R. R. (2008). The Revised NEO Personality Inventory (NEO-PI-R). In G. J. Boyle, G. Matthews, & D. H. Saklofske (Eds.), The SAGE handbook of personality theory and assessment, Vol. 2. Personality measurement and testing (pp.179–198). Sage Publications, Inc. https://doi.org/10.4135/9781849200479.n9

3. Ashton, M., & Lee, K. (2004). HEXACO Personality Inventory-Revised (HEXACO-PI-R) [Database record]. APA PsycTests. https://doi.org/10.1037/t03138-000

4. Brienza, L., Zennaro, A., Vitolo, E., & Andò, A. (2023). Affective Neuroscience Personality Scale (ANPS) and clinical implications: A systematic review. Journal of Affective Disorders, 320, 178–195. https://doi.org/10.1016/j.jad.2022.09.104

5. Aghababaei, N. & Arji, A. (2014). Well-being and the HEXACO model of personality. Personality and Individual Differences, 56(1), 139-142. http://dx.doi.org/10.1016/j.paid.2013.08.037

6. Cordis, C. (2024, February 9). How neuroticism can impact emotional well-being. CORDIS | European Commission. https://cordis.europa.eu/article/id/449194-how-neuroticism-can-impact-emotional-well-being

7. Leger, K. L., Turiano, N. A., Bowling, W., Burris, J. L., & Almeida, D. M. (2021). Personality Traits Predict Long-Term Physical Health via Affect Reactivity to Daily Stressors. Psychol Sci., 32(5), 755-765. 10.1177/0956797620980738