Social and Affective Mechanisms of Psychedelics: From Acute Dynamics to Long-Term Adaptation

Speaker: Dr. Rebecca Böhme 

Center for Social and Affective Neuroscience, Linköping University, Sweden 

Bibliography of the speaker: 

Dr. Rebecca Böhme is an Associate Professor at the Center for Social and Affective Neuroscience in Linköping, Sweden, where she studies the sense of self. Her research employs behavioral measures, functional brain imaging, and psychedelic interventions to understand how we establish a bodily self, how we connect with each other, and what happens to the self in psychiatric conditions. Rebecca studied biology and neuroscience at the University of Heidelberg and the Max Planck research school in Tübingen. For her PhD at the psychiatry department of Charité Berlin, she received the For Women in Science prize. Her research is funded by grants from the European Research Council and Vetenskapsrådet.  

Description of the general focus of the symposium: 

Psychedelics represent a unique class of psychoactive substances capable of profoundly influencing consciousness, perception, and mood. Importantly, a growing number of recent studies have demonstrated that psychedelics exhibit promising therapeutic efficacy across various mental health disorders. Relatedly, we have witnessed a substantial rise in the naturalistic (non-clinical) use of these substances, often driven by the intent of self-medication. However, the fact that the real-world impact of psychedelics is shaped by complex, context-dependent factors that cannot be replicated in controlled laboratory settings creates a critical knowledge gap, which can be addressed only by naturalistic studies. 

In both clinical and naturalistic settings, psychedelic-induced therapeutic breakthroughs are often attributed to profound alterations in social connection, affective states, and self-awareness. Therefore, the proposed symposium will present recent research exploring mechanisms of psychedelic action in the domains of affective and social neuroscience. The particular focus will be on the translational perspective, bridging the gap between studies in animal models and human participants, experimental and cross-sectional approaches, as well as linking acute neural dynamics with long-term effects. Considering the complex nature of the research problem, a broad range of methodological approaches will be presented, including rodent behavioral assays utilizing ultrasonic vocalizations, clinical outcome measures, and multimodal neuroimaging (EEG, fMRI) in naturalistic users. 

Specifically, first, we will discuss how the bodily ‘self’ serves as a foundation for social connection and how ketamine and psilocybin modulate boundaries between self and other in the context of touch and grief. Second, we will present preclinical insights into the anti-addictive potential of classical psychedelics, elucidating how they modulate social reward processing and affective states in rats. Third, we will consider the distinct physiological footprints of different compounds, contrasting the acute neural dynamics of psilocybin and ketamine with the intense "somatic catharsis" observed in the naturalistic use of 5-MeO-DMT. Finally, we will explore the controversial topic of how acute effects translate into long-term neuroadaptations in naturalistic psychedelic users. We will contrast fMRI evidence of altered emotional reactivity in experienced users with null findings from resting-state EEG, thereby challenging the assumption of persistent, global network reorganization. 

The symposium will thus present state-of-the-art research on the mechanisms of psychedelic action and discuss the challenges related to integrating findings from controlled laboratory settings with the complexity of naturalistic use. 

Psychedelics, the Self, and Grief 

Brief description of the talk:  

Touch is fundamental to the development and maintenance of a coherent bodily self, emerging from early experiences of both self-touch and caregiver contact. This sense of bodily self remains deeply interwoven with our capacity for social connection and mental health throughout life. In this talk, I will present findings from my randomized, double-blind, placebo-controlled fMRI study investigating how ketamine, an anesthetic and dissociative substance considered a non-classical psychedelic, alters self-other distinction in the context of affective touch. Ketamine administration led to dissociative experiences, reduced interoceptive awareness, and diminished neural differentiation between self- and other-touch in a temporoparietal region. These findings illuminate the neural mechanisms by which psychedelic substances might cause ego-dissolution and increased feelings of connectedness. In addition, I will introduce my new study on the use of psilocybin for prolonged grief disorder, where I will investigate whether psilocybin can support the adaptation to the loss experience by re-establishing the sense of self.