European Archives of Psychiatry and Clinical Neuroscience
February 20, 2020
G. C. Leal, I. D. Bandeira, F. S. Correia-Melo et al.
257 citations
A single intravenous infusion of arketamine (0.5 mg/kg) rapidly reduced depression severity in seven people with treatment-resistant depression. The Montgomery–Åsberg Depression Rating Scale score fell from an average of 30.7 before infusion to 10.4 after one day, a mean drop of 20.3 points. Dissociative side effects were nearly absent. The findings suggest arketamine may produce fast-onset and sustained antidepressant effects with a favorable safety profile, as previously observed in animals, but controlled trials are needed to confirm.
European Archives of Psychiatry and Clinical Neuroscience
April 18, 2016
Kenji Hashimoto, Takeharu Kakiuchi, Hiroyuki Ohba et al.
125 citations
Esketamine, but not R-ketamine, reduces dopamine D2/3 receptor binding availability in the monkey striatum, indicating that esketamine triggers dopamine release in this brain region. This dopamine release may underlie the psychotomimetic side effects of esketamine. R-ketamine, in contrast, does not affect striatal dopamine D2/3 binding, consistent with its proposed safer profile as a rapid antidepressant. The findings suggest a neurochemical difference between the two ketamine enantiomers that could explain their distinct side-effect profiles.
European Archives of Psychiatry and Clinical Neuroscience
February 27, 2024
Kenji Hashimoto
51 citations
The relationship between mystical experiences and antidepressant effects of ketamine and classic psychedelics like psilocybin is debated. Ketamine can cause dissociative symptoms such as out-of-body experiences, while psychedelics often produce hallucinogenic experiences like a sense of unity. Clinical studies indicate that dissociative symptoms from ketamine or esketamine are not directly linked to their antidepressant properties. The antidepressant potential of arketamine, which lacks dissociative side effects, remains unproven in large-scale trials. Activation of the serotonin 5-HT2A receptor is crucial for psychedelics' hallucinogenic effects, but its role in antidepressant action is unclear. This article examines whether mystical experiences enhance antidepressant outcomes.
European Archives of Psychiatry and Clinical Neuroscience
November 7, 2023
Ana-Maria Iorgu, Andrei-Nicolae Vasilescu, Natascha Pfeiffer et al.
2 citations
Psilocybin, unlike S-ketamine and MK-801, does not induce neuronal damage in the retrosplenial cortex of rats. Both S-ketamine and psilocybin are rapid-acting antidepressants that increase glutamate signalling and cortical hyperexcitation, but S-ketamine is known to cause neurotoxicity (Olney's lesions) in the retrosplenial cortex. Using immunohistochemical whole-brain mapping for heat shock protein 70 (HSP70) in rats, no HSP70-positive neurons were detected in the retrosplenial cortex of psilocybin-treated animals, whereas S-ketamine and MK-801 produced such markers. This suggests psilocybin may be safer for clinical use regarding neuronal damage.
European Archives of Psychiatry and Clinical Neuroscience
March 28, 2026
1 citation
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European Archives of Psychiatry and Clinical Neuroscience
June 23, 2026
Ilaria Bufalari, Lilya Abergel, Andrea Zagaria et al.
People with Maladaptive Daydreaming (MD)—compulsive, immersive daydreaming that disrupts daily life—report higher levels of dissociation and altered body awareness compared to those without MD. In a survey of 137 Italian-speaking adults, those with MD scored higher on dissociation, especially absorption and depersonalization, and lower on three aspects of interoception: attention regulation, body listening, and trusting bodily sensations. Network analyses placed maladaptive daydreaming as a central link between dissociation and interoception. The findings suggest that MD may involve using daydreaming to escape uncomfortable bodily states, and that improving interoception through interventions like mindfulness could help address MD and its dissociative features.
European Archives of Psychiatry and Clinical Neuroscience
June 5, 2026
Luis Sobrino-Conde, Antonio Arjona, Emma Osorio-Iriarte et al.
People with psychosis can be grouped into biotypes based on underlying pathological features rather than traditional diagnostic categories. One biotype (cluster 1) involves severe cognitive deficits, while another (cluster 2) involves moderate cognitive deficits. In a study of 113 patients, those in cluster 1 reported significantly more anomalous self-experiences—disturbances in the sense of self—than both healthy controls and cluster 2 patients. Cluster 2 patients showed only slight differences from controls. These findings suggest that severe disruptions in self-experience are a key feature of the biotype characterized by marked cognitive impairment, brain structure changes, and higher negative symptoms.