BMC Psychiatry
October 16, 2026
Morfeas Koumas, Markos Apostolakis, Evanthia Bella et al.
Abstract Background Opioid use disorder (OUD) is a chronic relapsing condition associated with substantial mortality. Although medications for opioid use disorder (MOUD) can be effective in reducing opioid use and improving treatment outcomes, relapse to drug use remains common, highlighting the need for adjunctive interventions that address relapse-relevant symptoms not fully targeted by MOUD...
Journal of Affective Disorders
March 15, 2025
Polymnia Georgiou, Cristan A Farmer, Gustavo C Medeiros et al.
24 citations
Subanesthetic doses of (R,S)-ketamine (ketamine) have demonstrated rapid and robust antidepressant effects in individuals with depression. However, individual variability in response to ketamine exists, and current biomarkers of ketamine treatment response are not entirely understood. Preclinical evidence suggests a link between hypothalamic-pituitary-adrenal (HPA) axis activation, a...
Biological Psychiatry
March 15, 2025
Anna Onisiforou, Andria Michael, Markos Apostolakis et al.
14 citations
Opioid use disorder (OUD) has reached epidemic proportions, with many countries facing high levels of opioid use and related fatalities. Although currently prescribed medications for OUD are considered lifesaving, they inadequately address negative affect and cognitive impairment, resulting in high relapse rates to nonmedical opioid use even years after drug cessation (protracted abstinence)....
Pharmacology, Biochemistry, and Behavior
February 1, 2023
Anna Onisiforou, Polymnia Georgiou, Panos Zanos
Major depression (MDD) is a serious neuropsychiatric disorder afflicting around 16-17 % of the global population and is accompanied by recurrent episodes of sadness and suicidal thoughts. Current pharmacological interventions take several weeks to even months for an improvement in depressive symptoms to emerge, with a significant percentage of individuals not responding to these medications at...
Journal of Neuroscience
January 3, 2023
Panos Zanos, Kyle A Brown, Polymnia Georgiou et al.
109 citations
Ketamine is a well-characterized NMDA receptor (NMDAR) antagonist, although the relevance of this pharmacology to its rapid (within hours of administration) antidepressant actions, which depend on mechanisms convergent with strengthening of excitatory synapses, is unclear. Activation of synaptic NMDARs is necessary for the induction of canonical long-term potentiation (LTP) leading to a...
Nature Neuroscience
August 30, 2022
Polymnia Georgiou, Panos Zanos, Ta-Chung M. Mou et al.
We show that the sex of human experimenters affects mouse behaviors and responses following administration of the rapid-acting antidepressant ketamine and its bioactive metabolite (2R,6R)-hydroxynorketamine. Mice showed aversion to the scent of male experimenters, preference for the scent of female experimenters and increased stress susceptibility when handled by male experimenters. This...
British Journal of Pharmacology
July 1, 2019
Panos Zanos, Jaclyn N. Highland, Xin Liu et al.
(R)-Ketamine (arketamine) may have utility as a rapidly acting antidepressant. While (R)-ketamine has lower potency than (R,S)-ketamine to inhibit NMDA receptors in vitro, the extent to which (R)-ketamine shares the NMDA receptor-mediated adverse effects of (R,S)-ketamine in vivo has not been fully characterised. Furthermore, (R)-ketamine is metabolised to (2R,6R)-hydroxynorketamine (HNK),...
Proceedings of the National Academy of Sciences
March 13, 2019
Panos Zanos, Jaclyn N. Highland, Brent W. Stewart et al.
153 citations
Significance Despite available medications for depression, currently approved antidepressants take months to exert therapeutic effects, and ∼30% of patients remain treatment resistant. In contrast, a single subanesthetic dose of ketamine exerts rapid (within hours) and sustained antidepressant actions. Preclinical studies indicate that the ketamine metabolite ( 2R , 6R )-hydroxynorketamine [(...
Pharmacological Reviews
June 26, 2018
Panos Zanos, Ruin Moaddel, Patrick J. Morris et al.
1,272 citations
Ketamine, a racemic mixture consisting of (S)- and (R)-ketamine, has been in clinical use since 1970. Although best characterized for its dissociative anesthetic properties, ketamine also exerts analgesic, anti-inflammatory, and antidepressant actions. We provide a comprehensive review of these therapeutic uses, emphasizing drug dose, route of administration, and the time course of these...
eNeuro
2017
Panos Zanos, Mackenzie E. Nelson, Jaclyn N. Highland et al.
109 citations
Abstract New antidepressant pharmacotherapies that provide rapid relief of depressive symptoms are needed. The NMDA receptor antagonist ketamine exerts rapid antidepressant actions in depressed patients but also side effects that complicate its clinical utility. Ketamine promotes excitatory synaptic strength, likely by producing high - frequency correlated activity in mood-relevant regions of...
Nature
April 24, 2016
Panos Zanos, Ruin Moaddel, Patrick J. Morris et al.
1,602 citations
Major depressive disorder affects around 16 per cent of the world population at some point in their lives. Despite the availability of numerous monoaminergic-based antidepressants, most patients require several weeks, if not months, to respond to these treatments, and many patients never attain sustained remission of their symptoms. The non-competitive, glutamatergic NMDAR (N-methyl-d-aspartate...