Tag: anxiety

Depressive and anxiety symptoms in current, previous, and no history of ME/CFS: NHIS 2022 analysis

Abstract:

Purpose: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is associated with anxiety and depressive symptoms. Psychological symptoms are predisposing factors for, as well as symptoms of, ME/CFS. Recovery from ME/CFS is poorly understood and heterogenous, and it is unclear how psychological symptoms may change with recovery. The aim of this study was to examine the associations of depressive and anxious symptoms among individuals with current, previous, and no history of ME/CFS.

Methods: National Health Interview Survey 2022 data were analyzed to assess ME/CFS status, as well as anxiety and depression burden. Adults (unweighted N = 27,651) in the United States reported sociodemographic and health behavior characteristics, with 453 adults reporting current ME/CFS, while 119 reported previous ME/CFS. Sample weights and variance estimation variables were implemented. Multivariable linear regression models were used to analyze the associations between ME/CFS status and anxiety and depression severity after adjusting for sociodemographic and health behavior variables.

Results: Participants were on average 48.1 years of age, and most identified as female (51.3%), white (76.6%), and not Hispanic or Latine (82.8%). Current and previous ME/CFS were associated with anxiety and depressive symptoms compared to individuals with no history of ME/CFS. Clinically significant levels of anxiety and depressive symptoms were substantial for individuals with current (37.6%; 49.0%) and previous (26.5%; 33.4%) ME/CFS compared to individuals with no history of ME/CFS (6.1%; 6.7%).

Conclusion: ME/CFS, regardless of current presence, was related to significantly greater anxiety and depressive symptom burden.

Source: Sirotiak Z, Adamowicz JL, Thomas EBK. Depressive and anxiety symptoms in current, previous, and no history of ME/CFS: NHIS 2022 analysis. Qual Life Res. 2024 Nov 23. doi: 10.1007/s11136-024-03854-2. Epub ahead of print. PMID: 39579271. https://link.springer.com/article/10.1007/s11136-024-03854-2 (Full text)

Psychological outcomes of COVID-19 survivors at sixth months after diagnose: the role of kynurenine pathway metabolites in depression, anxiety, and stress

Abstract:

Coronavirus disease 2019 (COVID-19) has resulted in long-term psychiatric symptoms because of the immunologic response to the virus itself as well as fundamental life changes related to the pandemic. This immune response leads to altered tryptophan (TRP)-kynurenine (KYN) pathway (TKP) metabolism, which plays an essential role in the pathophysiology of mental illnesses. We aimed to define TKP changes as a potential underlying mechanism of psychiatric disorders in post-COVID-19 patients.

We measured plasma levels of several TKP markers, including KYN, TRP, kynurenic acid (KYNA), 3-hydroxykynurenine (3-HK), and quinolinic acid (QUIN), as well as the TRP/KYN, KYNA/3-HK, and KYNA/QUIN ratios, in 90 post-COVID-19 patients (on the first day of hospitalization) and 59 healthy controls (on the first admission to the Check-Up Center). An online questionnaire that included the Depression, Anxiety and Stress Scale-21 (DASS-21) was used 6 months after the initial assessment in both groups.

A total of 32.2% of participants with COVID-19 showed depressive symptoms, 21.1% exhibited anxiety, and 33.3% had signs of stress at follow-up, while 6.6% of healthy controls exhibited depressive and anxiety symptoms and 18.6% had signs of stress. TRP and 3-HK were negative predictors of anxiety and stress, but KYN positively predicted anxiety and stress. Moreover, TRP negatively predicted depression, while KYNA/3-HK was a negative predictor of anxiety.

The correlation between depression, anxiety, and stress and TKP activation in COVID-19 could provide prospective biomarkers, especially the reduction in TRP and 3HK levels and the increase in KYN. Our results suggest that the alteration of TKP is not only a potential biomarker of viral infection-related long-term psychiatric disorders but also that the therapy targets future viral infections related to depression and anxiety.

Source: Kucukkarapinar M, Yay-Pence A, Yildiz Y, Buyukkoruk M, Yaz-Aydin G, Deveci-Bulut TS, Gulbahar O, Senol E, Candansayar S. Psychological outcomes of COVID-19 survivors at sixth months after diagnose: the role of kynurenine pathway metabolites in depression, anxiety, and stress. J Neural Transm (Vienna). 2022 Aug;129(8):1077-1089. doi: 10.1007/s00702-022-02525-1. Epub 2022 Jul 7. PMID: 35796878; PMCID: PMC9261222. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9261222/ (Full text)

Blood transcriptomic analyses reveal persistent SARS-CoV-2 RNA and candidate biomarkers in post-COVID-19 condition

Abstract:

With an estimated 65 million individuals affected by post-COVID-19 condition (also known as long COVID), non-invasive biomarkers are direly needed to guide clinical management. To address this pressing need, we used blood transcriptomics in a general practice-based case-control study. Individuals with long COVID were diagnosed according to WHO criteria, and validated clinical scales were used to quantify patient-reported outcomes.

Whole blood samples were collected from 48 individuals with long COVID and 12 control individuals matched for age, sex, time since acute COVID-19, severity, vaccination status, and comorbidities (appendix 1 p 2). Digital transcriptomic analysis was performed using the nCounter (Nanostring Technologies, Seattle, WA, USA) platform, as described for critical COVID-19.

Consequently, 212 genes were identified to be differentially expressed between individuals with long COVID and controls (figure A), of which 70 remained significant after adjustment for false discovery rate correction (appendix 1). Several viral RNAs were upregulated: nucleocapsid, ORF7a, ORF3a, Mpro (a nirmatrelvir plus ritonavir [Paxlovid] target), and antisense ORF1ab RNA. Specifically, the upregulation of antisense ORF1ab RNA suggests ongoing viral replication. SARS-CoV-2-related host RNAs (ACE2/TMPRSS2 receptors, DPP4/FURIN proteases) and RNAs prototypical for memory B-cells and platelets were also upregulated (figure A).

Multivariable logistic regression identified antisense SARS-CoV-2 and FYN RNA concentrations as independent predictors of long COVID (corrected for age and sex; appendix 1 p 2). Receiver operating characteristic curve analysis showed significant discrimination (area under curve [AUC] 0·94, 95% CI 0·86–1·00) between individuals with long COVID (n=48) and controls (n=12), with 93·8% sensitivity and 91·7% specificity (figure B).

Single biomarkers antisense SARS-CoV-2 (AUC 0·78, 0·65–0·90) and FYN RNA (AUC 0·89, 0·79–0·99) were significant predictors with lower sensitivity (52·1% and 72·9%, respectively) but similar specificity (91·7% and 100%, respectively; figure B). Upon summarising transcriptomic results into biological pathways, we found significantly decreased immunometabolism in individuals with long COVID, which was negatively correlated with the blood viral load (appendix 1 p 3).

A qualitative analysis of individual SARS-CoV-2 transcript positivity revealed significant differences between individuals with long COVID and controls for antisense (65% vs 25%), ORF7a (60% vs 25%), and nucleocapsid (50% vs 8%) RNAs (figure C). Similarly, the SARS-CoV-2 transcript positivity with respect to the total blood viral load was also significantly different (60% vs 8%).

By use of multivariable logistic regression, we found that age and sex were not associated with the distinction between a low and high viral RNA load status. Conversely, the number of comorbidities (odds ratio [OR] 1·61, 95% CI 1·14–2·49) and COVID vaccine doses (OR 0·36, 0·14–0·79) emerged as independent predictors of distinguishing between low and high viral RNA load status (appendix 2).

We found that viral and immune parameters, such as the antisense Orf1ab RNA concentrations and immunometabolism score, were also linked to the patient-reported anxiety or depression score. Individuals classified as having severe anxiety or depression (with a score of 4 and 5) displayed significantly higher antisense RNA concentrations and lower immunometabolism scores (p<0·05) than those categorised as mild (with scores of 1–3; figure D).

In conclusion, the associations among persistent viral RNA, immunometabolism, and patient-reported outcomes provide mechanistic insights for addressing the challenges posed by long COVID.

Source: Menezes SM, Jamoulle M, Carletto MP, Moens L, Meyts I, Maes P, Van Weyenbergh J. Blood transcriptomic analyses reveal persistent SARS-CoV-2 RNA and candidate biomarkers in post-COVID-19 condition. Lancet Microbe. 2024 Apr 24:S2666-5247(24)00055-7. doi: 10.1016/S2666-5247(24)00055-7. Epub ahead of print. PMID: 38677304. https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(24)00055-7/fulltext (Full text)

Microstructural brain abnormalities, fatigue, and cognitive dysfunction after mild COVID-19

Abstract:

Although some studies have shown neuroimaging and neuropsychological alterations in post-COVID-19 patients, fewer combined neuroimaging and neuropsychology evaluations of individuals who presented a mild acute infection. Here we investigated cognitive dysfunction and brain changes in a group of mildly infected individuals.

We conducted a cross-sectional study of 97 consecutive subjects (median age of 41 years) without current or history of psychiatric symptoms (including anxiety and depression) after a mild infection, with a median of 79 days (and mean of 97 days) after diagnosis of COVID-19. We performed semi-structured interviews, neurological examinations, 3T-MRI scans, and neuropsychological assessments. For MRI analyses, we included a group of non-infected 77 controls. The MRI study included white matter (WM) investigation with diffusion tensor images (DTI) and functional connectivity with resting-state functional MRI (RS-fMRI).

The patients reported memory loss (36%), fatigue (31%) and headache (29%). The quantitative analyses confirmed symptoms of fatigue (83% of participants), excessive somnolence (35%), impaired phonemic verbal fluency (21%), impaired verbal categorical fluency (13%) and impaired logical memory immediate recall (16%). The WM analyses with DTI revealed higher axial diffusivity values in post-infected patients compared to controls.

Compared to controls, there were no significant differences in the functional connectivity of the posterior cingulum cortex. There were no significant correlations between neuropsychological scores and neuroimaging features (including DTI and RS-fMRI).

Our results suggest persistent cognitive impairment and subtle white matter abnormalities in individuals mildly infected without anxiety or depression symptoms. The longitudinal analyses will clarify whether these alterations are temporary or permanent.

Source: Scardua-Silva, L., Amorim da Costa, B., Karmann Aventurato, Í. et al. Microstructural brain abnormalities, fatigue, and cognitive dysfunction after mild COVID-19. Sci Rep 14, 1758 (2024). https://doi.org/10.1038/s41598-024-52005-7  https://www.nature.com/articles/s41598-024-52005-7 (Full text)

Metabolomic and immune alterations in long COVID patients with chronic fatigue syndrome

Introduction: A group of SARS-CoV-2 infected individuals present lingering symptoms, defined as long COVID (LC), that may last months or years post the onset of acute disease. A portion of LC patients have symptoms similar to myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), which results in a substantial reduction in their quality of life. A better understanding of the pathophysiology of LC, in particular, ME/CFS is urgently needed.

Methods: We identified and studied metabolites and soluble biomarkers in plasma from LC individuals mainly exhibiting ME/CFS compared to age-sex-matched recovered individuals (R) without LC, acute COVID-19 patients (A), and to SARS-CoV-2 unexposed healthy individuals (HC).

Results: Through these analyses, we identified alterations in several metabolomic pathways in LC vs other groups. Plasma metabolomics analysis showed that LC differed from the R and HC groups. Of note, the R group also exhibited a different metabolomic profile than HC. Moreover, we observed a significant elevation in the plasma pro-inflammatory biomarkers (e.g. IL-1α, IL-6, TNF-α, Flt-1, and sCD14) but the reduction in ATP in LC patients. Our results demonstrate that LC patients exhibit persistent metabolomic abnormalities 12 months after the acute COVID-19 disease. Of note, such metabolomic alterations can be observed in the R group 12 months after the acute disease. Hence, the metabolomic recovery period for infected individuals with SARS-CoV-2 might be long-lasting. In particular, we found a significant reduction in sarcosine and serine concentrations in LC patients, which was inversely correlated with depression, anxiety, and cognitive dysfunction scores.

Conclusion: Our study findings provide a comprehensive metabolomic knowledge base and other soluble biomarkers for a better understanding of the pathophysiology of LC and suggests sarcosine and serine supplementations might have potential therapeutic implications in LC patients. Finally, our study reveals that LC disproportionally affects females more than males, as evidenced by nearly 70% of our LC patients being female.

Source: Saito Suguru, Shahbaz Shima, Luo Xian, Osman Mohammed, Redmond Desiree, Cohen Tervaert Jan Willem, Li Liang, Elahi Shokrollah. Metabolomic and immune alterations in long COVID patients with chronic fatigue syndrome. Frontiers in Immunology, Vol 15, 2024. DOI=10.3389/fimmu.2024.1341843  https://www.frontiersin.org/articles/10.3389/fimmu.2024.1341843/full (Full text)

Characteristics of long COVID and the impact of COVID-19 vaccination on long COVID 2 years following COVID-19 infection: prospective cohort study

Abstract:

This prospective cohort study aimed to identify characteristics of long COVID and any potential mitigating effects of COVID-19 vaccinations in patients 24 months following COVID-19 infection. Adult patients diagnosed with COVID-19 between February 17, 2020, and March 24, 2020, were scheduled to visit the study hospital four times (6, 12, 18, and 24 months after infection) to assess their symptoms, quality of life, and mental health. Among the 235 patients, 121 (51.5%) completed the study visits. Of these, 59.5% were female, with a median age of 52 years. Mild to moderate disease severity were identified in 101 (83.4%) patients.

A total of 75 participants (62.0%) were still experiencing long COVID symptoms 24 months after acute infection. Fatigue, amnesia, difficulty concentrating, and insomnia were the most common symptoms. The frequency of neuropsychiatric symptoms did not differ based on vaccination status or the number of doses received. Quality of life improved over time for the participants, but 32.2% of respondents still reported anxiety/depression at the end of the study. Overall, our cohort demonstrates that long COVID can persist up to 24 months after COVID-19 infection, affecting mental health and quality of life.

Source: Kim, Y., Bae, S., Chang, HH. et al. Characteristics of long COVID and the impact of COVID-19 vaccination on long COVID 2 years following COVID-19 infection: prospective cohort study. Sci Rep 14, 854 (2024). https://doi.org/10.1038/s41598-023-50024-4 https://www.nature.com/articles/s41598-023-50024-4 (Full text)

Exploring the central mechanism of mind-regulation electroacupuncture in treatment of chronic fatigue syndrome with anxiety and depression comorbidity based on functional magnetic resonance imaging

Abstract:

in English, Chinese

Objectives: To observe the changes in the regional homogeneity (ReHo) and functional brain network in treatment of chronic fatigue syndrome (CFS) with anxiety and depression comorbidity with the mind-regulation electroacupuncture (EA), using resting-state functional magnetic resonance imaging (rs-fMRI).

Methods: Thirty CFS patients with anxiety and depression comorbidity were enrolled from medical staffs as the observation group. The other 30 healthy subjects were recruited from medical university students as the control group, matching gender, age and education years with the observation group. No any acupuncture intervention was delivered in the control group, and EA for regulating the mind was operated in the observation group. Main points were the emotional area of Sun‘s scalp acupuncture, the regions 1 and 8 of Sun‘s abdominal acupuncture. Supplementary acupoints included Baihui (GV 20), Guanyuan (CV 4) and bilateral.

Results: The scores of the five domains in MFI-20 (i.e. general fatigue, physical fatigue, mental fatigue, reduced motivation and reduced activity), the total score of MFI-20, and the scores of SDS, SAS and PSQI in the observation group before treatment were higher than those of the control group (P<0.05). Except the score of reduced motivation in MFI-20, the scores of the other domains and the total score of MFI-20, as well as the scores of SDS, SAS and PSQI after treatment were lower than those before treatment in the observation group (P<0.05).

Compared with the values before treatment, ReHo value was increased in the the right precuneus and decreased in the left inferior temporal gyrus and the left angular gyrus of the brain in the observation group after treatment. In the observation group, when compared with the control group, ReHo values were increased in the left inferior cerebral lobe, the interhemispheric region, the right occipital lobe and the thalamus; and it was reduced in the left middle temporal gyrus, the right posterior central gyrus, the right middle temporal gyrus, the right orbital middle frontal gyrus, the paracentral lobule and the right fusiform gyrus before treatment.

In the observation group, the functional connectivity was decreased between the right thalamus and the left posterior central gyrus, the right hippocampus and the right fusiform gyrus before treatment, respectively; it was re-constructed after treatment between the right thalamus and the left posterior central gyrus, and the right fusiform gyrus.

Compared with the control group, the functional connectivity between the right thalamus and the left posterior central gyrus, the right hippocampus, and the right fusiform gyrus was reduced before treatment; while after treatment, the functional connectivity was reduced between the right thalamus and the hippocampus in the observation group. With Spearman correlation analysis between the differential brain regions and the scores of MFI-20, SAS, SDS and PSQI, it was found that the left middle temporal gyrus, the paracentral lobule, the right precuneus, and the left inferior temporal gyrus had a partial positive correlation with the above clinical scales; and the interhemispheric region, the thalamus, the right fusiform gyrus, and the right middle temporal gyrus showed a partial negative correlation.

Conclusions: There is the decrease of ReHo in many brain regions and the numbers of the local brain functional network connectivity in CFS patients with anxiety and depression comorbidity. The mind-regulation electroacupuncture therapy may relieve the clinical symptoms of the patients through adjusting the abnormal brain regions and activating emotion-related brain regions.

Source: Zeng X, Feng C, Zhang M, Cheng W, Sun Z, Yang T. Exploring the central mechanism of mind-regulation electroacupuncture in treatment of chronic fatigue syndrome with anxiety and depression comorbidity based on functional magnetic resonance imaging. Zhongguo Zhen Jiu. 2023 Jan 12;44(1):3-11. English, Chinese. doi: 10.13703/j.0255-2930.20230603-k0003. PMID: 38191152. https://pubmed.ncbi.nlm.nih.gov/38191152/

The effect of nirmatrelvir-ritonavir on the long-term risk of neuropsychiatric sequelae following COVID-19

Abstract:

The retrospective cohort was conducted to assess the effect of nirmatrelvir-ritonavir (NMV-r) on the long-term risk of neuropsychiatric sequela following COVID-19. TriNetX research network was used to identify nonhospitalized adult patients who tested positive for severe acute respiratory syndrome coronavirus 2 infection or were diagnosed with COVID-19 between March 1, 2020 and July 1, 2022. Further propensity score matching method was used to create two matched cohorts with and without receiving NMV-r.

The primary outcome was the incidence of neuropsychiatric sequela within a 90-day to 1-year period following a diagnosis of COVID-19. After screening 119 494 527 electronic health records, two matched cohorts of each 27 194 patients were identified. During the follow-up period, the NMV-r group demonstrated a reduced risk of any neuropsychiatric sequelae compared to the control group (odds ratio [OR], 0.634; 95% confidence interval [CI], 0.604-0.667).

In comparison with the control group, the patient treated with NMV-r exhibited a markedly diminished risk of developing neurocognitive sequela (OR, 0.377; 95% CI, 0.325-0.439) and psychiatric sequela (OR, 0.629; 95% CI, 0.593-0.666). In addition, patients treated with NMV-r had a significantly reduced risk of developing dementia (OR, 0.365; 95% CI, 0.255-0.522), depression (OR, 0.555; 95% CI, 0.503-0.612), insomnia (OR, 0.582; 95% CI, 0.508-0.668) and anxiety disorder (OR, 0.645 95% CI, 0.600-0.692). Moreover, the beneficial effect of NMV-r on the neuropsychiatric sequelae was observed across further subgroup analyses.

Among nonhospitalized COVID-19 patients, who at risk of disease progression, the use of NMV-r is associated with a reduction in the long-term risk of neuropsychiatric sequela, including dementia, depression, insomnia and anxiety disorder. It may be necessary to re-evaluate the use of NMV-r, as a preventive measure to reduce the risk of severe acute disease and post-acute adverse mental health outcomes.

Source: Liu TH, Wu JY, Huang PY, Tsai YW, Lai CC. The effect of nirmatrelvir-ritonavir on the long-term risk of neuropsychiatric sequelae following COVID-19. J Med Virol. 2023 Jul;95(7):e28951. doi: 10.1002/jmv.28951. PMID: 37436873. https://pubmed.ncbi.nlm.nih.gov/37436873/

Tryptophan catabolites, inflammation, and insulin resistance as determinants of chronic fatigue syndrome and affective symptoms in long COVID

Abstract:

Critical COVID-19 disease is accompanied by depletion of plasma tryptophan (TRY) and increases in indoleamine-dioxygenase (IDO)-stimulated production of neuroactive tryptophan catabolites (TRYCATs), including kynurenine (KYN). The TRYCAT pathway has not been studied extensively in association with the physiosomatic and affective symptoms of Long COVID.

In the present study, we measured serum TRY, TRYCATs, insulin resistance (using the Homeostatic Model Assessment Index 2-insulin resistance, HOMA2-IR), C-reactive protein (CRP), physiosomatic, depression, and anxiety symptoms in 90 Long COVID patients, 3–10 months after remission of acute infection.

We were able to construct an endophenotypic class of severe Long COVID (22% of the patients) with very low TRY and oxygen saturation (SpO2, during acute infection), increased kynurenine, KYN/TRY ratio, CRP, and very high ratings on all symptom domains. One factor could be extracted from physiosomatic symptoms (including chronic fatigue-fibromyalgia), depression, and anxiety symptoms, indicating that all domains are manifestations of the common physio-affective phenome.

Three Long COVID biomarkers (CRP, KYN/TRY, and IR) explained around 40% of the variance in the physio-affective phenome. The latter and the KYN/TRY ratio were significantly predicted by peak body temperature (PBT) and lowered SpO2 during acute infection. One validated latent vector could be extracted from the three symptom domains and a composite based on CRP, KYN/TRY, and IR (Long COVID), and PBT and SpO2 (acute COVID-19).

In conclusion, the physio-affective phenome of Long COVID is a manifestation of inflammatory responses during acute and Long COVID, and lowered plasma tryptophan and increased kynurenine may contribute to these effects.

Source: Al-Hakeim HK, Khairi Abed A, Rouf Moustafa S, Almulla AF, Maes M. Tryptophan catabolites, inflammation, and insulin resistance as determinants of chronic fatigue syndrome and affective symptoms in long COVID. Front Mol Neurosci. 2023 Jun 2;16:1194769. doi: 10.3389/fnmol.2023.1194769. PMID: 37333619; PMCID: PMC10272345. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10272345/ (Full text)

Prevalence of mental health problems among children with long COVID: A systematic review and meta-analysis

Abstract:

Introduction: The number of children with mental health problems has more than doubled since the COVID-19 pandemic. However, the effect of long Covid on children’s mental health is still debatable. Recognising long Covid as a risk factor for mental health problems in children will increase awareness and screening for mental health problems following COVID-19 infection, resulting in earlier intervention and lower morbidity. Therefore, this study aimed to determine the proportion of mental health problems post-COVID-19 infection in children and adolescents, and to compare them with the population with no previous COVID-19 infection.

Methodology: A systematic search was done in seven databases using pre-defined search terms. Cross-sectional, cohort and interventional studies reporting the proportion of mental health problems among children with long COVID in the English language from 2019 to May 2022 were included. Selection of papers, extraction of data and quality assessment were done independently by two reviewers. Studies with satisfactory quality were included in meta-analysis using R and Revman software programmes.

Results: The initial search retrieved 1848 studies. After screening, 13 studies were included in the quality assessments. Meta-analysis showed children who had previous COVID-19 infection had more than two times higher odds of having anxiety or depression, and 14% higher odds of having appetite problems, compared to children with no previous infection. The pooled prevalence of mental health problems among the population were as follows; anxiety: 9%(95% CI:1, 23), depression: 15%(95% CI:0.4, 47), concentration problems: 6%(95% CI: 3, 11), sleep problems: 9%(95% CI:5, 13), mood swings: 13% (95%CI:5, 23) and appetite loss: 5%(95% CI:1, 13). However, studies were heterogenous and lack data from low- and middle-income countries.

Conclusion: Anxiety, depression and appetite problems were significantly increased among post-COVID-19 infected children, compared to those without a previous infection, which may be attributed to long COVID. The findings underscore the importance of screening and early intervention of children post-COVID-19 infection at one month and between three to four months.

Source: Mat Hassan N, Salim HS, Amaran S, Yunus NI, Yusof NA, Daud N, et al. (2023) Prevalence of mental health problems among children with long COVID: A systematic review and meta-analysis. PLoS ONE 18(5): e0282538. https://doi.org/10.1371/journal.pone.0282538 https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0282538 (Full text)