Acta neuropsychiatrica
June 1, 2007
Steven M Miller
74 citations
A separate hard problem faces the scientific study of consciousness beyond the well-known 'hard problem' in philosophy of mind. This problem arises from the distinction between the neural correlates of consciousness (NCC) and the neural constitution of consciousness. The correlation/constitution distinction poses a genuine challenge for a science of phenomenal consciousness. Several additional hard problems also confront the field. Scientists and philosophers should address these problems and consider the possibility that some may be intractable. Ultimate epistemic limits in studying phenomenal consciousness do not threaten physicalist or materialist ontologies but do inform our understanding of consciousness and its place in nature.
Acta neuropsychiatrica
July 25, 2025
Guillaume Thuery, Christopher Sheridan, Patricia Iusan et al.
4 citations
This narrative review synthesizes clinical and preclinical research on how 5-HT2A receptor psychedelics interact with the immune system. The evidence shows these compounds have direct immunomodulatory properties, including downregulation of gene regulators like NF-κB and reduced expression of cytokines such as TNF-α, IL-6, and IL-1β in both the central and peripheral nervous systems. These effects are accompanied by modulation of corticotrophin releasing hormone, adrenocorticotrophic hormone, and cortisol. The immunomodulation occurs through pathways involving serotonin receptors, the Sigma-1 receptor, and the TrkB receptor, as well as indirectly via the HPA axis. The review identifies that modulation of brain glia and glial-neuronal interactions remains to be determined, representing a promising direction for future research on the therapeutic potential of these psychedelics for mental health and brain disorders.
Acta neuropsychiatrica
April 25, 2024
Karl Sandström, Olli Kampman, Peter Asellus
1 citation
In a retrospective review of 46 patients who received intravenous ketamine for psychiatric treatment between 2015 and 2018, no significant difference was found in the number or duration of hospital admissions before versus after treatment. The response rate was 31% and the remission rate 21%. Although intravenous ketamine reduced depressive symptoms in complex patients in a real-world clinical setting, this did not lead to fewer hospitalizations, underscoring the multifaceted challenges of implementing this treatment in practice.
Acta neuropsychiatrica
June 10, 2026
Helerin Raikkerus, Andrea Bujour, Mark Kennedy et al.
A systematic review of research on psychedelics for ADHD identified only six studies meeting inclusion criteria. One randomized controlled trial found no statistically important difference compared to placebo. Three cross-sectional studies reported positive effects of psychedelics, and one found statistically important improvement measured by the Child Bipolar Questionnaire. A case study showed improvement in depressive symptoms and functioning with ketamine. The evidence is insufficient to recommend psychedelics for ADHD, and it remains unknown whether patients whose depression responds to ketamine also have ADHD. No research examined how psychedelics affect patient subgroups with different causes of symptoms.
Acta neuropsychiatrica
April 10, 2026
Ashkan Veysi, Daniela Atanasovski, Maryam Ardalan et al.
Psilocybin, a psychedelic known for hallucinogenic and potential therapeutic effects, alters gene expression in rat brains in a region-specific manner. Ninety minutes after injection, several genes were upregulated across multiple brain regions, including Nfkbia and Sgk1 in all studied areas and Ddit4 in four regions. Other genes like Gpd1, Apold1, Sox9, Tsc22d3, and Slc2a1 changed in two regions. Psilocybin did not affect genes related to serotonin signaling or other neurotransmitter systems. Many affected genes are known to be activated by glucocorticoids, suggesting a link to stress hormone pathways.