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Roger Ho

National University of Singapore, National University Hospital

27 papers in the library · 1,447 citations · publishing 2016-2026

Papers

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Cardiac Consequences Associated with Psychedelic Use: A Systematic Review of Lysergic Acid Diethylamide, 3,4-Methylenedioxymethamphetamine, and 5-Hydroxytryptamine 2B-Mediated Valvular Heart Disease.

Pharmacopsychiatry February 5, 2026 Tianyi Xu, Sabrina Wong, Gia Han Le et al.

Serotonergic psychedelics, such as lysergic acid diethylamide, and psilocybin, and the entactogen 3,4-methylenedioxymethamphetamine exhibit agonist activity at the 5-hydroxytryptamine 2B receptor, a signalling pathway known to mechanistically mediate drug-induced valvular heart disease. This systematic review evaluates whether chronic or repeated use of psychedelics and...

Effects of glutamatergic modulators on striatal activation, functional connectivity and reward in persons with major depressive disorder and healthy controls: A systematic review of fMRI studies.

Journal of Affective Disorders February 1, 2026 Kayla M Teopiz, Sabrina Wong, Gia Han Le et al.

Convergent evidence suggests that disrupted reward processing may be associated with observed alterations in frontostriatal activity in persons with major depressive disorder (MDD). Replicated evidence suggests that glutamatergic modulators may benefit persons experiencing disrupted reward function compared to healthy controls (HC). Herein, we systematically reviewed functional magnetic...

Is the antidepressant efficacy of ketamine and esketamine mediated via opioid mechanisms?

European Psychiatry 2026 Andy Lu, Heidi Xu, Gia Han Le et al. 4 citations

The reported mixed findings suggest that the opioid system may exert a partial mediating effect of ketamine in TRD. However, given the inconsistent attenuation of ketamine's antidepressant effects by opioid receptor antagonists, the opioid system likely functions as a context-dependent modulator rather than a primary mediator, particularly at standard antidepressant doses.

A Global Population-Based Study on the Association Between Ketamine and Esketamine With Suicidality Using WHO VigiBase.

The Journal of Clinical Psychiatry July 7, 2025 Angela T H Kwan, Moiz Lakhani, Joshua D. Rosenblat et al. 2 citations

Background: Ketamine and esketamine have been reported to rapidly alleviate various parameters of suicidality, with antisuicidal effects that may be independent of their rapid-acting antidepressant effects. However, it remains unclear whether ketamine and/or esketamine are associated with the emergence or worsening of suicidality. Methods: In this global observational pharmacovigilance cohort...

The sigma-1 receptor: a mechanistically-informed therapeutic target for antidepressants.

Expert Opinion on Therapeutic Targets June 1, 2025 Naomi Xiao, Liyang Yin, Kayla M Teopiz et al. 5 citations

The mechanism of action of antidepressants is not fully ascertained. In addition to monoamines, disparate other effectors are also implicated in the molecular and cellular effects of chronic stress including neurogenesis, neurodifferentiation, and neuroplasticity. Evidence suggests sigma-1 receptors (S1Rs) as a putative target and possible mediator of antidepressant activity. Data from...

Hepatic adverse events associated with ketamine and esketamine: A population-based disproportionality analysis.

Journal of Affective Disorders April 1, 2025 Angela T H Kwan, Moiz Lakhani, Kayla M Teopiz et al. 11 citations

To determine whether there is disproportionate reporting of hepatobiliary disorders in the United States (US) FDA Adverse Event Reporting System (FAERS) for individuals prescribed ketamine or esketamine. We identified Medical Dictionary for Regulatory Activities (MedDRA) terms in the FAERS related to hepatobiliary disorders. Formulations of ketamine and esketamine were evaluated for the...

Efficacy of esketamine for perinatal depression: a systematic review and meta-analysis.

CNS Spectrums October 31, 2024 Sabrina Wong, Gia Han Le, Angela T H Kwan et al. 10 citations

Postpartum depression (PPD), now referred to as perinatal depression, is a prevalent and debilitating mood disorder that reduces health-related quality of life (HRQoL) and psychosocial functioning. Esketamine, which is efficacious in adults with treatment-resistant depression and individuals with depression and suicidality, is also analgesic in pain management during childbirth labour. Herein,...

A replication study using the World Health Organization pharmacovigilance database (VigiBase®) to evaluate whether an association between ketamine and esketamine and alcohol and substance misuse exists.

Journal of Affective Disorders October 15, 2024 Angela T H Kwan, Joshua D. Rosenblat, Rodrigo B. Mansur et al. 13 citations

Ketamine and esketamine are increasingly prescribed in the treatment of resistant mood disorders and persons at risk of suicide. Ketamine is a drug of misuse with increasing non-therapeutic use in the general population. Herein, our aim was to determine whether ketamine and/or esketamine are disproportionately associated with reports of substance and/or alcohol misuse. Replicating a similar...

Number needed to treat (NNT) for ketamine and esketamine in adults with treatment-resistant depression: A systematic review and meta-analysis.

Journal of Affective Disorders July 1, 2024 Cameron N Calder, Angela T H Kwan, Kayla M Teopiz et al. 31 citations

Ketamine has been established as efficacious in adults living with Treatment-resistant Depression (TRD). Toward providing a quantifiable estimate of the clinical meaningfulness of the therapeutic benefit of ketamine, herein, we conduct a systematic review that aims to report the Number Needed to Treat (NNT) and the Number Needed to Harm (NNH). This systematic review searched Embase,...

Spectral signatures of psilocybin, lysergic acid diethylamide (LSD) and ketamine in healthy volunteers and persons with major depressive disorder and treatment-resistant depression: A systematic review.

Journal of Affective Disorders June 15, 2024 Gia Han Le, Sabrina Wong, Sebastian Badulescu et al. 25 citations

Electrophysiologic measures provide an opportunity to inform mechanistic models and possibly biomarker prediction of response. Serotonergic psychedelics (SPs) (i.e., psilocybin, lysergic acid diethylamide (LSD)) and ketamine represent new investigational and established treatments in mood disorders respectively. There is a need to better characterize the mechanism of action of these agents. We...

A comparison between psilocybin and esketamine in treatment-resistant depression using number needed to treat (NNT): A systematic review.

Journal of Affective Disorders April 1, 2024 Sabrina Wong, Angela T H Kwan, Kayla M Teopiz et al. 19 citations

Inadequate outcomes with monoamine-based treatments in depressive disorders are common and provide the impetus for mechanistically-novel treatments. Esketamine is a proven treatment recently approved for adults with Treatment-Resistant Depression (TRD) while psilocybin is an investigational treatment. Translation of the clinical meaningfulness for these foregoing agents in adults with TRD is...

Dextromethorphan-Bupropion for the Treatment of Depression: A Systematic Review of Efficacy and Safety in Clinical Trials.

CNS Drugs October 1, 2023 Dania Akbar, Taeho Greg Rhee, Felicia Ceban et al.

A significant proportion of adults with major depressive disorder (MDD) do not respond to treatments which are currently used in clinical practice such as first-generation monoamine-based antidepressants. The objective of this systematic review was to assess the efficacy, safety, and mechanisms of action of AXS-05, a combination of the NMDA-receptor antagonist dextromethorphan with bupropion,...

Treatment‐resistant depression: definition, prevalence, detection, management, and investigational interventions

World Psychiatry September 15, 2023 Roger S McIntyre, Mohammad Alsuwaidan, Bernhard T Baune et al. 712 citations

Treatment‐resistant depression (TRD) is common and associated with multiple serious public health implications. A consensus definition of TRD with demonstrated predictive utility in terms of clinical decision‐making and health outcomes does not currently exist. Instead, a plethora of definitions have been proposed, which vary significantly in their conceptual framework. The absence of a...

Features of urban green spaces associated with positive emotions, mindfulness and relaxation

Scientific Reports November 30, 2022 Agnieszka Olszewska-Guizzo, Angelia Sia, Anna Fogel et al. 95 citations

There is an established consensus among researchers that contact with nature improves mental health, wellbeing, and quality of life in urbanised environments. Studies tend to examine the health impacts of nature without identifying specific physical and spatial landscape features that could guide health-promoting design of urban green spaces. A growing body of evidence suggests that landscape...

Ketamine as Potential Treatment for Postpartum Depression: A Narrative Review

Annals of Clinical Psychiatry November 1, 2022 David C J Chen-Li, Leanna M.W. Lui, Joshua D. Rosenblat et al. 22 citations

BACKGROUND: Postpartum depression (PPD) is a severe, debilitating mood disorder with consequences for both mothers and children, highlighting the need for rapid-acting and effective treatments for PPD. The aim of this narrative review is to synthesize the available literature on the administration of ketamine for PPD and propose ketamine as a viable and advantageous treatment. METHODS: A search...

A Research Domain Criteria (RDoC)-Guided Dashboard to Review Psilocybin Target Domains: A Systematic Review.

CNS Drugs October 1, 2022 Niloufar Pouyan, Zahra Halvaei Khankahdani, Farnaz Younesi Sisi et al. 16 citations

Preliminary results from randomized controlled studies as well as identified molecular, cellular, and circuit targets of select psychedelics (e.g., psilocybin) suggest that their effects are transdiagnostic. In this review, we exploit the Research Domain Criteria (RDoC) transdiagnostic framework, to synthesize extant literature on psilocybin. We aimed to identify RDoC-based effects of...

A review of potential neuropathological changes associated with ketamine

Expert Opinion on Drug Safety May 3, 2022 Danica Nogo, Hana Nazal, Yuetong Song et al. 17 citations

INTRODUCTION: Ketamine is an established intervention for treatment-resistant depression (TRD). However, long-term adverse effects with repeated doses remain insufficiently characterized. Although several animal models have shown N-methyl-D-aspartate glutamate receptor antagonists to produce various neuropathological reactions, attention surrounding the risk of brain lesions has been minimal....

Hallucinogen persisting perceptual disorder: a scoping review covering frequency, risk factors, prevention, and treatment

Expert Opinion on Drug Safety April 15, 2022 Marcus A. Doyle, Susan Ling, Leanna M.W. Lui et al. 24 citations

INTRODUCTION: Hallucinogen persisting perception disorder (HPPD) affects a subset of persons who use hallucinogens and is defined as the repeated experience of hallucinations and other perceptual disturbances as a result of prior intoxications. As select hallucinogens are under development for the treatment of selectmental disorders, there is a need to better characterize this disorder. AREAS...

Frequency analysis of symptomatic worsening following ketamine infusions for treatment resistant depression in a real-world sample: Results from the canadian rapid treatment center of excellence.

Psychiatry Research 2022 Joshua D. Di Vincenzo, Orly Lipsitz, Nelson B Rodrigues et al. 11 citations

Antidepressants are associated with symptomatic worsening in a subgroup of patients. Replicated evidence has demonstrated rapid and robust antidepressant effects with intravenous (IV) ketamine in treatment resistant depression (TRD); however, the risk of ketamine worsening depressive symptoms in a subgroup of patients remains unknown. Herein we report a retrospective analysis on the rates of...

Molecular Mechanisms of Psilocybin and Implications for the Treatment of Depression

CNS Drugs November 17, 2021 Susan Ling, Felicia Ceban, Leanna M.W. Lui et al. 123 citations

Therapeutic deficiencies with monoaminergic antidepressants invites the need to identify and develop novel rapid-acting antidepressants. Hitherto, ketamine and esketamine are identified as safe, well-tolerated rapid-acting antidepressants in adults with treatment-resistant depression, and also mitigate measures of suicidality. Psilocybin is a naturally occurring psychoactive alkaloid and...

Do sleep changes mediate the anti‐depressive and anti‐suicidal response of intravenous ketamine in treatment‐resistant depression?

Journal of Sleep Research June 16, 2021 Nelson B Rodrigues, Roger S McIntyre, Orly Lipsitz et al. 28 citations

Summary Sleep disturbances are commonly reported in patients with treatment‐resistant depression (TRD). Available data have shown that intravenous (IV) ketamine is an effective treatment for patients with TRD and growing data suggest ketamine may improve overall sleep architecture. In the present study, we evaluated whether changes in sleep symptoms mediated the anti‐depressive and/or...

Efficacy of dextromethorphan for the treatment of depression: a systematic review of preclinical and clinical trials

Expert Opinion on Emerging Drugs January 2, 2021 Amna Majeed, Jiaqi Xiong, Kayla M Teopiz et al. 48 citations

INTRODUCTION: The large percentage of adults with major depressive disorder (MDD) insufficiently responding and/or tolerating conventional monoamine-based antidepressants invites the need for mechanistically novel treatments. Convergent evidence implicates glutamatergic signaling as a potential therapeutic target in MDD. AREAS COVERED: The synthesis herein of preclinical and clinical studies...

Effectiveness of intravenous ketamine in mood disorder patients with a history of neurostimulation

CNS Spectrums December 10, 2020 Nelson B Rodrigues, Ashley N. Siegel, Orly Lipsitz et al. 17 citations

BACKGROUND: Patients unsuccessfully treated by neurostimulation may represent a highly intractable subgroup of depression. While the efficacy of intravenous (IV) ketamine has been established in patients with treatment-resistant depression (TRD), there is an interest to evaluate its effectiveness in a subpopulation with a history of neurostimulation. METHODS: This retrospective, posthoc...

The effectiveness of intravenous ketamine in adults with treatment-resistant major depressive disorder and bipolar disorder presenting with prominent anxiety: Results from the Canadian Rapid Treatment Center of Excellence

Journal of Psychopharmacology October 11, 2020 Roger S McIntyre, Nelson B Rodrigues, Orly Lipsitz et al. 19 citations

Background: Individuals meeting criteria for treatment-resistant depression (TRD) are differentially affected by high levels of anxiety symptoms. Aims: There is a need to identify the efficacy of novel rapid-onset treatments in adults with mood disorders and comorbid anxious-distress. Methods: This study included patients with treatment-resistant major depressive disorder (MDD) or bipolar...

The emerging role of psilocybin and MDMA in the treatment of mental illness

Expert Review of Neurotherapeutics September 21, 2020 Hartej Gill, Barjot Gill, David C J Chen-Li et al. 62 citations

Psychedelics, such as psilocybin and MDMA, offer an alternative avenue of therapy for many mental health disorders. Available evidence indicates that psychedelics may offer a single-dose, rapid effect model that have robust effects with treatment-resistant mental disorders and a unique advantage as a possible monotherapy for mental illness. Novel clinical trials that evaluate the safety,...