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

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 COVERED: A scoping review of the literature on HPPD was completed from inception to July 2021. Topics covered in the review herein include treatments for HPPD, prevalence or incidence data on HPPD among different classes of hallucinogens, risk factors for HPPD, and data pertaining to the pathophysiology of HPPD. EXPERT OPINION: Hallucinogen persisting perception disorder appears to be an uncommon yet serious event associated with prior hallucinogen exposure. The renewed interest in psychedelics as potential treatment options for select mental disorders, especially agents with hallucinogenic potential, provides the impetus to characterize HPPD in its frequency, risk and protective factors, key characteristics, as well as other clinical and treatment-related factors.

Fatigue and cognitive impairment in Post-COVID-19 Syndrome: A systematic review and meta-analysis.

IMPORTANCE: COVID-19 is associated with clinically significant symptoms despite resolution of the acute infection (i.e., post-COVID-19 syndrome). Fatigue and cognitive impairment are amongst the most common and debilitating symptoms of post-COVID-19 syndrome. OBJECTIVE: To quantify the proportion of individuals experiencing fatigue and cognitive impairment 12 or more weeks following COVID-19 diagnosis, and to characterize the inflammatory correlates and functional consequences of post-COVID-19 syndrome. DATA SOURCES: Systematic searches were conducted without language restrictions from database inception to June 8, 2021 on PubMed/MEDLINE, The Cochrane Library, PsycInfo, Embase, Web of Science, Google/Google Scholar, and select reference lists. STUDY SELECTION: Primary research articles which evaluated individuals at least 12 weeks after confirmed COVID-19 diagnosis and specifically reported on fatigue, cognitive impairment, inflammatory parameters, and/or functional outcomes were selected. DATA EXTRACTION & SYNTHESIS: Two reviewers independently extracted published summary data and assessed methodological quality and risk of bias. A meta-analysis of proportions was conducted to pool Freeman-Tukey double arcsine transformed proportions using the random-effects restricted maximum-likelihood model. MAIN OUTCOMES & MEASURES: The co-primary outcomes were the proportions of individuals reporting fatigue and cognitive impairment, respectively, 12 or more weeks following COVID-19 infection. The secondary outcomes were inflammatory correlates and functional consequences associated with post-COVID-19 syndrome. RESULTS: The literature search yielded 10,979 studies, and 81 studies were selected for inclusion. The fatigue meta-analysis comprised 68 studies, the cognitive impairment meta-analysis comprised 43 studies, and 48 studies were included in the narrative synthesis. Meta-analysis revealed that the proportion of individuals experiencing fatigue 12 or more weeks following COVID-19 diagnosis was 0.32 (95% CI, 0.27, 0.37; p < 0.001; n = 25,268; I2 = 99.1%). The proportion of individuals exhibiting cognitive impairment was 0.22 (95% CI, 0.17, 0.28; p < 0.001; n = 13,232; I2 = 98.0). Moreover, narrative synthesis revealed elevations in proinflammatory markers and considerable functional impairment in a subset of individuals. CONCLUSIONS & RELEVANCE: A significant proportion of individuals experience persistent fatigue and/or cognitive impairment following resolution of acute COVID-19. The frequency and debilitating nature of the foregoing symptoms provides the impetus to characterize the underlying neurobiological substrates and how to best treat these phenomena. STUDY REGISTRATION: PROSPERO (CRD42021256965).

Prevalence of type 2 diabetes mellitus, impaired fasting glucose, general obesity, and abdominal obesity in patients with bipolar disorder: A systematic review and meta-analysis.

OBJECTIVES: The study herein aimed to assess the prevalence of type 2 diabetes mellitus (T2DM), impaired fasting glucose (IFG), as well as general and abdominal obesity in patients with bipolar disorder (BD). We also compared the prevalence of T2DM and general obesity in patients with BD with age- and gender-matched healthy controls. METHODS: A systematic search of Embase, Medline, PubMed, and APA PsycArticles was conducted from inception to June 2021 without language restrictions. Methodological quality was assessed using the Newcastle-Ottawa Scale (NOS) modified for case-control studies. RESULTS: A total of forty-nine studies were included in this analysis. The pooled prevalence of T2DM was 9.6% (95% CI, 7.3-12.2%). Patients with BD had a nearly 1.6 times greater risk of developing T2DM compared to their age- and gender-matched controls (RR=1.57, 95% CI 1.36-1.81, p<0.001). In the present analysis, IFG is defined as a fasting plasma glucose (FPG) ≥ 100 mg/dL (FPG≥100) with a prevalence of 22.4% (95% CI, 16.7-28.7%), or as an FPG equal to or greater than 110 mg/d (FPG≥110) with a prevalence of 14.8% (95% CI, 10.8-19.3%). The prevalence of general obesity (BMI≥30 kg/m2) was 29.0% (95% CI, 22.8-35.6%); the risk of obesity was almost twice the rate reported in patients with BD compared to controls (RR=1.67, 95% CI 1.32-2.12, p<0.001). We also observed that more than half of the BD participants had abdominal obesity (i.e., prevalence of 51.1%; 95% CI, 45.0-57.3%). LIMITATIONS: A significant degree of heterogeneity was detected. Sources of heterogeneity included differences in study designs, inclusion criteria, measurement tools, and data analysis methods. CONCLUSION: Bipolar disorder is associated with a higher prevalence of T2DM, IFG, general obesity, and abdominal obesity. Type 2 diabetes mellitus and obesity are significantly more prevalent in patients with BD than in their age- and gender-matched controls. STUDY REGISTRATION: CRD42021258431.

Molecular Mechanisms of Psilocybin and Implications for the Treatment of Depression.

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 non-selective agonist at many serotonin receptors, especially at serotonin 5-HT2A receptors, and is found in the Psilocybe genus of mushrooms. Preliminary studies with psilocybin have shown therapeutic promise across diverse populations including major depressive disorder. The pharmacodynamic mechanisms mediating the antidepressant and psychedelic effects of psilocybin are currently unknown but are thought to involve the modulation of the serotonergic system, primarily through agonism at the 5-HT2A receptors and downstream changes in gene expression. It is also established that indirect effects on dopaminergic and glutamatergic systems are contributory, as well as effects at other lower affinity targets. Along with the direct effects on neurochemical systems, psilocybin alters neural circuitry and key brain regions previously implicated in depression, including the default mode network and amygdala. The aim of this review is to synthesize the current understanding of the receptor pharmacology and neuronal mechanisms underlying the psychedelic and putative antidepressant properties of psilocybin.

Trace amine-associated receptor 1 (TAAR1): Potential application in mood disorders: A systematic review.

There is a need for innovation with respect to therapeutics in psychiatry. Available evidence indicates that the trace amine-associated receptor 1 (TAAR1) agonist SEP-363856 is promising, as it improves measures of cognitive and reward function in schizophrenia. Hedonic and cognitive impairments are transdiagnostic and constitute major burdens in mood disorders. Herein, we systematically review the behavioural and genetic literature documenting the role of TAAR1 in reward and cognitive function, and propose a mechanistic model of TAAR1's functions in the brain. Notably, TAAR1 activity confers antidepressant-like effects, enhances attention and response inhibition, and reduces compulsive reward seeking without impairing normal function. Further characterization of the responsible mechanisms suggests ion-homeostatic, metabolic, neurotrophic, and anti-inflammatory enhancements in the limbic system. Multiple lines of evidence establish the viability of TAAR1 as a biological target for the treatment of mood disorders. Furthermore, the evidence suggests a role for TAAR1 in reward and cognitive function, which is attributed to a cascade of events that are relevant to the cellular integrity and function of the central nervous system.

CO: A chemical ontology for identification of functional groups and semantic comparison of small molecules.

A novel chemical ontology based on chemical functional groups automatically, objectively assigned by a computer program, was developed to categorize small molecules. It has been applied to PubChem and the small molecule interaction database to demonstrate its utility as a basic pharmacophore search system. Molecules can be compared using a semantic similarity score based on functional group assignments rather than 3D shape, which succeeds in identifying small molecules known to bind a common binding site. This ontology will serve as a powerful tool for searching chemical databases and identifying key functional groups responsible for biological activities.