Substance use disorders (SUDs) remain among the most persistent global public health challenges. Despite decades of pharmacological and behavioral innovation, relapse rates remain high, and many individuals struggle to find treatments that address both the physiological and psychological drivers of addiction. Substance use is frequently intertwined with trauma, depression, anxiety, emotional dysregulation, and diminished self-awareness, factors that conventional treatments often fail to fully address.
Traditional approaches to SUDs, including pharmacotherapies such as methadone and naltrexone and behavioral interventions such as cognitive-behavioral therapy, primarily focus on symptom management and harm reduction. Although these strategies demonstrate short-term effectiveness, they are frequently limited by low adherence and high relapse rates. In many cases, they do not adequately address the maladaptive cognitive patterns and rigid neural circuits that sustain addictive behaviors.
In recent years, psychedelic-assisted therapy has re-emerged as a distinct therapeutic approach to addiction treatment. By targeting core neurobiological and psychological mechanisms underlying substance use disorders, psychedelic therapies may support more durable treatment outcomes than conventional interventions.
Pharmacological Classes of Psychedelics in Addiction Treatment
Psychedelics used in therapeutic contexts can be broadly categorized based on their primary neuropharmacological mechanisms: serotonin receptor agonists, N-methyl-D-aspartate (NMDA) receptor antagonists, and multi-target compounds acting on several receptor systems. These distinctions are critical for understanding both therapeutic potential and associated risks.
Classic Psychedelics Acting on the 5-HT2A Receptor
Classic psychedelics such as psilocybin, lysergic acid diethylamide (LSD), and dimethyltryptamine (DMT) primarily act as agonists at the serotonin 5-HT2A receptor. Activation of this receptor produces profound alterations in perception, cognition, and emotional processing, while also enhancing neuroplasticity and disrupting rigid, maladaptive brain networks.
Clinical studies have shown that psilocybin- and LSD-assisted therapies can support sustained reductions in alcohol and tobacco use. Notably, one or two doses of psilocybin, when combined with structured psychotherapy, have been associated with significant decreases in heavy drinking days and long-term abstinence in nicotine dependence, with benefits persisting for up to nine to twelve months. These outcomes contrast with the relapse rates often observed in conventional SUD treatments.
Ketamine and NMDA Receptor Antagonism in Addiction Treatment
Ketamine represents a mechanistically distinct class of psychedelic-related compounds. As an NMDA receptor antagonist, ketamine modulates glutamatergic signaling, promotes rapid synaptic remodeling, and increases brain-derived neurotrophic factor (BDNF) expression. These effects may help restore reward-related neural circuits and reduce craving and withdrawal symptoms, particularly in opioid and cocaine use disorders.
However, ketamine’s clinical utility is constrained by dissociative side effects, bladder toxicity with repeated exposure, and its own potential for misuse, underscoring the need for careful clinical oversight.
Ibogaine and Other Multi-Target Psychedelic Compounds
Ibogaine, a psychoactive alkaloid derived from Tabernanthe iboga, exhibits a complex pharmacological profile, interacting with κ-opioid, NMDA, sigma, and serotonin systems. It has shown particular promise in reducing withdrawal symptoms and cravings in opioid and stimulant use disorders. However, ibogaine presents substantial safety concerns, including cardiotoxicity and neurotoxicity, which currently limit its clinical applicability.
Ayahuasca, a traditional Amazonian brew containing DMT and monoamine oxidase inhibitors, has also attracted attention for its potential role in treating substance use disorders. Beyond its pharmacological effects, the therapeutic outcomes associated with ayahuasca appear strongly influenced by the ceremonial and psychosocial contexts in which it is administered. Observational studies report reductions in alcohol use and improvements in psychological well-being, although controlled clinical trials remain limited.
Neurobiological Mechanisms of Psychedelic Therapy
At the neurobiological level, the therapeutic effects of psychedelics are closely associated with their capacity to modulate brain networks involved in self-awareness, emotional regulation, and cognitive flexibility. Activation of 5-HT2A receptors initiates intracellular signaling cascades involving phospholipase C, ERK, and mTOR pathways, ultimately promoting synaptic protein synthesis, dendritic spine growth, and structural neuroplasticity.
Psychedelics also enhance glutamatergic transmission and increase AMPA and NMDA receptor activity, resulting in elevated release of brain-derived neurotrophic factor (BDNF). BDNF–TrkB signaling reinforces synaptic stability and neural resilience, facilitating the reorganization of dysfunctional reward and emotional circuits implicated in addiction.
Neuroimaging studies consistently demonstrate that psychedelics reduce activity within the default mode network (DMN), a brain network associated with rigid self-referential thinking and rumination. Because DMN hyperactivity is commonly observed in addiction, its temporary disruption may facilitate a functional reset of maladaptive neural patterns, supporting long-term behavioral change.
Substance-Specific Mechanisms of Psychedelic Therapy
Emerging evidence suggests that psychedelics may exert substance-specific therapeutic effects by targeting neural circuits implicated in different forms of addiction.
Alcohol Use Disorder
Alcohol use disorder is associated with dysfunction in the prefrontal cortex, impairing executive control and decision-making. Psychedelic therapies may help restore cognitive flexibility and improve behavioral regulation.
Opioid Use Disorder
In opioid use disorder, alterations in the insula and amygdala contribute to craving and emotional dysregulation. Psychedelics may help reduce these symptoms by modulating emotional processing and reward pathways.
Nicotine Dependence
Nicotine addiction is strongly driven by habit formation and reward circuitry. Psychedelic experiences may disrupt entrenched behavioral patterns and enhance motivation for behavioral change.
These distinctions highlight the potential for tailoring psychedelic-assisted therapies to specific substance use disorders.
The Role of Set and Setting in Psychedelic Therapy
Set and setting are critical determinants of both the safety and efficacy of psychedelic therapy. Set refers to an individual’s mindset, expectations, and psychological state, while setting encompasses the physical, social, and therapeutic environment in which the experience occurs.
Historical and contemporary evidence indicate that well-managed set and setting enhance therapeutic outcomes, whereas poorly controlled conditions increase the likelihood of adverse experiences. The relative importance of these factors varies across compounds: ayahuasca practices often rely heavily on ritual and communal support, ibogaine administration requires intensive medical supervision, and psilocybin and LSD are typically administered within structured clinical environments that include preparation and integration sessions.
Individual differences, including genetic variability, personality traits, and mental health history, also influence responses to psychedelic substances. Comprehensive screening, psychological preparation, and post-session integration therapy are therefore essential components of responsible clinical practice.
Challenges and Limitations of Psychedelic Therapies
Despite their therapeutic promise, psychedelic therapies face significant challenges. Psychological risks include acute anxiety, panic reactions, and, in vulnerable individuals, the potential triggering of psychosis. Physiological risks vary by compound, with ibogaine presenting particular concerns due to cardiotoxicity and metabolic variability.
Legal and regulatory barriers further constrain research and clinical implementation, as many psychedelic substances remain classified as Schedule I drugs in many jurisdictions. However, regulatory reforms in several countries indicate a gradual shift toward expanded research access and carefully regulated therapeutic use.
Future research should prioritize large-scale controlled trials, biomarker development, and personalized treatment approaches to improve both safety and efficacy.
Current Understanding and Future Directions
Psychedelic-assisted therapies represent a novel and potentially transformative approach to treating substance use disorders. By addressing the neural and psychological foundations of addiction rather than solely its symptoms, psychedelic therapies may complement existing treatments and support more durable recovery outcomes. Although substantial challenges remain, the growing body of evidence supports cautious optimism regarding their future integration into addiction treatment frameworks.
AUTHOR
MSc Student in Neuroscience, background in Cell and Molecular Biology
Sogol is a graduate student with a growing passion for understanding the biological mechanisms that underlie brain function and human behavior.
Her academic journey began in Tehran, where she earned a Bachelor’s degree from the Islamic Azad University of Pharmaceutical Sciences (IAUPS). Wanting to deepen her knowledge of human biology, she pursued a Master’s in Medical Biology at the University of Salzburg (Paris Lodron University) in Austria.
However, before completing that program, her curiosity about the brain led her to Greece, where she continued her studies with a Master’s in Neuroscience at the National and Kapodistrian University of Athens (NKUA).
Alongside her academic work, Sogol conducts research on psychedelics, examining how these compounds influence neurobiology, resilience, emotional processing, and human behavior. As a mental well-being and life coach, she supports her clients in cultivating clarity, emotional balance, and meaningful personal growth, integrating scientific insight with a human-centered approach.
