Addiction involves at minimum three distinct pathophysiological problems: erosion of inhibitory control over compulsive behavior (“it's okay, just one more time”), atrophy of the reward infrastructure that makes sober life feel worth living (“everything feels a little flat”), and the physiological trap of withdrawal that forecloses cessation attempts before they begin (“I can't do this”). No single drug class addresses all three. What psychedelics offer, beyond their direct clinical promise, is a set of pharmacological probes that helps us understand how each problem actually works.
Classic serotonergic psychedelics (psilocybin, LSD, DMT) act on the 5-HT2A receptor, triggering a cascade of cortical glutamate release that activates mTOR and BDNF signaling and drives rapid structural remodeling of neurons. LSD and related compounds also bind directly to TrkB, the BDNF receptor, at a site that overlaps with conventional antidepressants, a mechanism independent of the classic hallucinogenic 5-HT2A pathway (Moliner et al., 2023). The result is a window of unusually high neural plasticity.
What this teaches us about addiction is less about reversing specific damage and more about revision of learned patterns. Compulsive behavior can be understood as a rigid prior: a deeply entrenched expectation that drug-paired cues predict reward, one that resists updating even in the face of contradicting evidence. Psychedelics may disrupt entrenched cue-response circuits, allowing individuals to disengage from compulsive patterns, by relaxing the precision of the high-level priors that encode them, liberating bottom-up information that can help revise pathological, entrenched beliefs (Carhart-Harris & Friston, 2019). This shows up at the network level as reduced default mode network connectivity, with low DMN connectivity profiles serving as a biomarker for craving severity in alcohol use disorder, explaining roughly a third of the variance in craving in one cohort (Fede et al., 2019). The lesson isn't that psychedelics repair a broken circuit. It's that addiction's grip depends partly on rigid priors, and that rigidity is pharmacologically addressable, at least transiently.
Ibogaine points to a different lesson. Long-term heavy use of opioids and stimulants drives compensatory changes in the ventral tegmental area, including a homeostatic increase in GABAergic inhibition onto dopaminergic neurons that blunts their net output and reward responses in the absence of the drug, a tolerance-related adaptation that helps explain why early sobriety often feels flat rather than relieving, and why that flatness itself becomes a relapse driver (Mazei-Robison et al., 2011; Allichon et al., 2026).
“Addiction is better understood as a multifaceted failure rather than a single problem to be patched.”
A single ibogaine administration increases GDNF expression in the midbrain for up to 24 hours (He et al., 2005), and this induction may trigger an autocrine loop that sustains GDNF synthesis well beyond elimination of the parent compound, a mechanism proposed to reverse the biochemical adaptations to chronic drug exposure in the reward system (Marton et al., 2019). What this teaches us: the reward system's depletion under chronic use is not necessarily permanent, and a brief pharmacological signal can apparently initiate a repair process that supports the survival and function of VTA dopaminergic neurons, helping restore their baseline excitability through a distinct, trophic mechanism rather than by directly reversing the GABAergic tolerance adaptation described above. The next-generation analog oxa-noribogaine recapitulates this through a KOR-dependent mechanism, producing long-lasting suppression of opioid-seeking behavior after a single dose in rodent models (Havel et al., 2024), suggesting the lesson generalizes beyond the original iboga alkaloid.
The third lesson is the most mechanistically distinct. Ibogaine's broader receptor pharmacology, including partial agonism at mu and kappa opioid receptors, non-competitive antagonism at α3β4 nicotinic receptors, and a neuroadaptive effect on the endogenous opioid system that reverses opioid tolerance (Mash, 2023), shows that withdrawal itself can be pharmacologically interrupted, independent of any plasticity or repair mechanism. This is why ibogaine is often described less as a treatment and more as a circuit breaker: it acts on the withdrawal process itself, not just the underlying disease.
Taken together, these compounds suggest addiction is better understood as a multifaceted failure, of control, of reward, and of the physiological ability to even attempt cessation, rather than a single problem to be patched.
References
- Allichon, M.C., Espinosa, J., Cole, R.H., Ko, M.C., Vanhoutte, P., & Joffe, M.E. (2026). Mu-opioid and nociceptin receptors show divergent, cell-type-specific actions in the mesocorticolimbic reward system in opioid use disorder. Frontiers in Cellular Neuroscience, 20, 1774384.
- Carhart-Harris, R.L. & Friston, K.J. (2019). REBUS and the Anarchic Brain: Toward a Unified Model of the Brain Action of Psychedelics. Pharmacological Reviews.
- Fede, S.J. et al. (2019). Resting state connectivity associated with alcohol use disorder severity. Cited in: Default Mode Network Modulation by Psychedelics: A Systematic Review, International Journal of Neuropsychopharmacology.
- Govender, D., Moloko, L., Papathanasopoulos, M., Tumba, N., Owen, G., & Calvey, T. (2024). Ibogaine administration following repeated morphine administration upregulates myelination markers 2′,3′-cyclic nucleotide 3′-phosphodiesterase (CNP) and myelin basic protein (MBP) mRNA and protein expression in the internal capsule of Sprague Dawley rats. Frontiers in Neuroscience, 18, 1378841. doi:10.3389/fnins.2024.1378841.
- Havel, V. et al. (2024). Oxa-iboga alkaloids lack cardiac risk and disrupt opioid use in animal models. Nature Communications, 15, 8118. doi:10.1038/s41467-024-51856.
- He, D.Y. et al. (2005). Glial cell line-derived neurotrophic factor mediates the desirable actions of the anti-addiction drug ibogaine against alcohol consumption. Journal of Neuroscience, 25(3), 619-628. doi:10.1523/JNEUROSCI.3959-04.2005.
- Marton, S. et al. (2019). Ibogaine Administration Modifies GDNF and BDNF Expression in Brain Regions Involved in Mesocorticolimbic and Nigral Dopaminergic Circuits. Frontiers in Pharmacology.
- Mazei-Robison, M.S., et al., (2011). Role for mTOR signaling and neuronal activity in morphine-induced adaptations in ventral tegmental area dopamine neurons. Neuron.
- Moliner, R. et al. (2023). Psychedelics promote plasticity by directly binding to BDNF receptor TrkB. Nature Neuroscience.