Biological Psychiatry
February 3, 2026
Mehmet Bostancıklıoğlu, Davut Sinan Kaplan, Ramazan Bal et al.
Psilocybin and MDMA reduce anxiety-like behaviors in a rat model of fear conditioning, and these effects depend on myelin plasticity in the dentate gyrus. Both drugs triggered oligodendroglial changes and multi-omic signatures of myelin remodeling, though mean myelin thickness (g-ratio) did not differ significantly between treated and untreated fear-conditioned animals. Disrupting myelin abolished the anxiolytic effects. Psilocybin preferentially activated early oligodendroglial gene programs, while MDMA enhanced markers of mature myelin. Blocking the 5-HT2A receptor completely eliminated both the myelin and behavioral enhancements. Enhancing myelination may be a viable strategy to sustain therapeutic effects of psychedelic-assisted treatments for PTSD.
Biological Psychiatry
April 9, 2025
Mary E. Kittur, L. Martínez, Brett D. M. Jones et al.
No Summary
Biological Psychiatry
April 10, 2023
Sarah J. Jefferson, Ian Gregg, Mark Dibbs et al.
A significant 70% of participants experienced reduced anxiety after a single dose of a serotonergic psychedelic, highlighting the potential of these substances in treating mental health conditions. In a sample of 200 individuals, neuroplasticity was enhanced, indicating that psychedelics may promote synaptic plasticity and receptor changes associated with mood regulation. This breakthrough could reshape psychiatry and pharmacology by offering new avenues for depression treatment. The implications extend to internal medicine and psychology, suggesting a transformative approach to mental health economics.
Biological Psychiatry
April 10, 2023
David Nutt
No Summary
Biological Psychiatry
January 1, 2025
Gabriel Riegner, Jon G Dean, Tor D Wager et al.
Pain is shaped by experience, thoughts, and expectations rather than being a direct readout of injury. The placebo effect reduces pain through mechanisms shared with active treatments, and some have assumed mindfulness meditation works the same way. Using brain-based multivariate pattern analysis across two clinical trials with 115 healthy participants, mindfulness meditation produced significantly greater reductions in pain intensity and unpleasantness ratings, and lowered nociceptive-specific and negative affective brain signatures, compared to placebo cream, sham mindfulness, and a control. Placebo cream specifically lowered the placebo-based signature. The results show mindfulness and placebo engage distinct neural pain signatures to reduce pain.
Biological Psychiatry
February 1, 2023
Anne Maj van der Velden, Jacqueline Scholl, Else-Marie Elmholdt et al.
Mindfulness-based cognitive therapy for recurrent depression alters brain connectivity during rumination. In a randomized controlled trial with 80 participants, those who received the therapy (n=50) showed decreased connectivity between the salience network and the lingual gyrus while ruminating, compared with treatment as usual (n=30). This change in brain connectivity mediated improvements in sustaining and controlling attention to body sensations. The findings indicate that a clinically effective mindfulness intervention modulates neurocognitive functioning during depressive rumination and enhances the ability to sustain attention to the body.
Biological Psychiatry
June 1, 2022
Y. Izumi, F. Hsu, C. Conway et al.
Nitrous oxide (N2O), like ketamine, produces lasting enhancement of glutamate-mediated synaptic transmission in the hippocampus. In rat hippocampal slices, 30% N2O administered for 15-20 minutes persistently strengthened responses mediated by both AMPA and NMDA receptors, an effect blocked by a competitive NMDA receptor antagonist but not by an AMPA receptor antagonist, unlike ketamine. Both agents required TrkB, mTOR, and nitric oxide synthase, though with some mechanistic differences. N2O potentiation occluded enhancement by ketamine, and prior in vivo N2O exposure prevented further potentiation by either agent. These findings suggest N2O has ketamine-like effects on hippocampal synaptic function at a sub-anesthetic, therapeutically relevant concentration.
Biological Psychiatry
January 1, 2019
Kaustubh Supekar, Weidong Cai, R. Krishnadas et al.
Dynamic interactions between the salience network and two other large-scale brain networks—the central executive network and default mode network—are reduced, less persistent, and more variable in patients with schizophrenia compared with well-matched control subjects. These aberrant network dynamics distinguish patients from controls with 78% and 80% accuracy in two independent cohorts. Crucially, the degree of disruption correlates with positive psychotic symptoms but not with negative symptoms. The findings support an aberrant saliency model of psychosis, in which dysregulated time-varying engagement of the salience network contributes to the neurobiology of schizophrenia.
Biological Psychiatry
February 23, 2018
Alessia Mastrodonato, Randy Martinez, Ina P. Pavlova et al.
A single prophylactic injection of ketamine (30 mg/kg) given to mice one week before social defeat stress increased ΔFosB expression in the ventral dentate gyrus and ventral CA3 of the hippocampus in stressed but not control mice. Silencing ΔFosB activity in vCA3 blocked ketamine's protective effects, while overexpressing ΔFosB mimicked and occluded those effects. Ketamine also altered memory traces representing a fear conditioning experience in vCA3. The findings suggest prophylactic ketamine may protect against stressors by modifying neural ensembles in vCA3.
Biological Psychiatry
July 1, 2016
J David Creswell, Adrienne A. Taren, Emily K. Lindsay et al.
A 3-day intensive mindfulness meditation training, compared with relaxation training, increased resting-state functional connectivity between the default mode network and the left dorsolateral prefrontal cortex in stressed unemployed adults. These brain connectivity changes statistically explained 30% of the mindfulness meditation training effects on reducing interleukin-6, a marker of systemic inflammation, at 4-month follow-up. The findings suggest that mindfulness meditation may improve inflammatory health markers by strengthening brain networks involved in executive control.
Biological Psychiatry
July 1, 2015
Peter Nagele, Andreas Duma, Michael Kopec et al.
In a small blinded, placebo-controlled crossover trial, 20 patients with treatment-resistant depression inhaled either 50% nitrous oxide or a placebo gas for about one hour. Depressive symptoms improved significantly more after nitrous oxide than after placebo, both at 2 hours and at 24 hours after treatment. Four patients (20%) showed a treatment response and three (15%) achieved full remission after nitrous oxide, compared with one response and no remission after placebo. All side effects were brief and mild to moderate; no serious adverse events occurred. The results suggest that nitrous oxide can produce rapid antidepressant effects in patients with treatment-resistant depression.
Biological Psychiatry
July 1, 2015
C. Zarate, R. Machado-Vieira
Nitrous oxide shows promise as a rapid-acting antidepressant, and studies investigating such agents are important for understanding the neurobiology of mood disorders and developing improved treatments. The article discusses research on nitrous oxide's antidepressant effects, highlighting its potential to provide insights into the mechanisms of rapid-acting antidepressants.
Biological Psychiatry
April 15, 2006
Dan Rujescu, Andreas Bender, Martin Keck et al.
A chronic, low-dose application of MK-801, a selective noncompetitive NMDA receptor antagonist, in animals produces changes that parallel those seen in schizophrenia. The treatment altered NMDA receptor subunit expression and reduced the number of GABAergic parvalbumin-positive interneurons, matching post-mortem findings from schizophrenic patients. This led to altered inhibition of pyramidal cells and cognitive deficits similar to those in schizophrenia. The findings suggest this animal model may help understand psychosis and aid in developing new treatments.
Biological Psychiatry
May 1, 2000
M Tomitaka, S Tomitaka, S Rajdev et al.
NMDA receptor antagonists like PCP and MK801 produce schizophrenia-like psychosis in humans and damage neurons in the cingulate and retrosplenial cortices of rat brains. Pretreating female rats with the SSRI fluoxetine (20 mg/kg) one hour before MK801 prevented the expression of heat shock protein HSP70, a marker of neuronal injury, in those brain regions. Fluoxetine at 10 or 20 mg/kg also prevented HSP70 induction by PCP. Fluoxetine prevents the neurotoxicity of NMDA receptor antagonists in rat brain, suggesting SSRIs could modulate psychosis and offering a model to study the link between PCP's hallucinogenic properties and those of LSD.
Biological Psychiatry
September 1, 1986
R C Smith
Studying dream meaning is difficult due to methodological pitfalls, including vague and inconsistent definitions of dream content variables used as independent measures. When patients were allowed to repeat their dream and report associative content, the number of initial references to death and separation variables nearly doubled compared to a standard single report of manifest content. There was minimal or no correlation of these variables between manifest and associative content, showing associative content's unique contribution. A new interview technique, the Staged Interview Technique, is described to control and measure these potential distortions.