The deposit left by the covid in the body is still latent many months later.
As a burden that accompanies people who have passed the disease, the risk of developing some psychiatric and neurological ailments, such as psychotic episodes, dementia, brain fog or epilepsy, continues to rise up to two years after diagnosis, according to a study published in
The Lancet Psychiatry
Not all associated diseases, yes, have such a long shadow.
The risk of suffering from anxiety and mood disorders is not greater than that of people suffering from another respiratory infection, the researchers conclude.
There are many unknowns yet to be revealed about the possible impact of covid on the body in the short, medium and long term.
Like persistent covid, which draws heterogeneous clinical pictures with more than 200 different sequelae and it is still unknown why it arises, who it affects and for how long.
The most refined study on its prevalence calculated that one in eight infected people has prolonged symptoms, but why and who is affected by the different sequelae, to what degree or what effects the coronavirus infection will have is still up in the air.
The endless hangover of the coronavirus that affects millions: one in eight infected has prolonged symptoms
A new investigation, promoted by scientists from the University of Oxford, reopens that melon about how long that drag that covid leaves is.
In this case, specifically in neuropsychiatric ailments.
Since the beginning of the pandemic, the scientific community has warned that covid increased the risk of developing certain psychiatric and neurological diseases, but the Oxford researchers, they explain in their article, wanted to answer several unresolved questions: if these risks elevated levels returned to normal over time and when, if they were similar by age and in children, and if those risk profiles changed in the heat of the evolution of the different variants of the virus.
To do this, they collected clinical information in databases from 1.28 million people with covid, most of them from the United States, but also from Spain, Australia, Bulgaria and Malaysia, among other countries.
And they crossed them with a group made up of as many other participants who had had other respiratory infections.
“To our knowledge, this is the first study with a comparison cohort that assesses the risks of a variety of neurological and psychiatric outcomes of COVID up to two years after the index Sars-CoV-2 infection.
We found that the risks of post-Covid neurological and psychiatric outcomes follow different trajectories,” the scientists explain in the article.
Some conditions are going to be two or three times more common after dealing with covid than other respiratory infections
Paul Harrison, University of Oxford
Paul Harrison, professor at the University of Oxford and lead author of the study, has clarified, in a meeting with the media, that these risks are not dramatic and differ substantially according to age groups.
It is not about a risk 10 or 100 times higher, he has said.
“I think the worst odds ratio is two or three: Some things are going to be two to three times more common after dealing with covid than other [respiratory] infections.
But those things that are relatively more common also tend to be rare things, ”he pointed out.
The investigation revealed that the risks of common psychiatric disorders, such as anxiety or depression, disappeared within two months.
"Good news", assessed, in the same meeting with journalists, Max Taquet, a psychiatry researcher at the National Institute for Health Research and co-author of the study: "The excess risk of some disorders, in particular anxiety disorders , disappeared in three months with no general excess of cases in two years.
What that means is that two years after infection, the number of people with Covid who had a diagnosis of depression or an anxiety disorder was the same as people who had another respiratory tract infection.
And that is very reassuring,” he added.
There will be no tsunami of dementia
The downside, however, is that the same does not happen in some of the 14 ailments analyzed in the research.
The risks of cognitive deficits (such as brain fog), dementia, psychotic disorders, epilepsy and seizures continued to increase up to two years after diagnosis.
“From the risk horizons, if no anxiety disorder has been diagnosed within two months after the covid diagnosis, from that moment on, the patient can be sure that their risk is no longer higher than after another Respiratory infection.
If a patient had developed an ischemic stroke within two months of the covid diagnosis, it is plausible that the covid diagnosis contributed (either directly or indirectly) to the onset of it,
The researchers have clarified that their results do not mean, for example, "a tsunami" of cases of dementia and it may be that the increase in psychotic disorders is not chronic, but specific episodes that occur at a specific time.
But this potential increase in diagnoses should not be neglected, they add.
The scientists admit, however, that one of the limitations of their study is that they do not know "the severity or course of each disorder after diagnosis, or whether or not they are similar after covid and after other respiratory infections."
The scientists warn, in any case, that these risk trajectories "are informative for public health" and serve as a guide for patients and health professionals to be "attentive" to possible "late sequelae".
Harrison also warns, in terms of health planning, of his findings: "The results have important implications for patients and health services, since they suggest that new cases of neurological conditions related to covid infection are likely to occur during a considerable time after the pandemic has subsided.
Our work also highlights the need for more research to understand why this is happening after Covid and what can be done to prevent or treat these conditions."
Increased risk of seizures in children
By age, the researchers also found that the risk profiles and trajectories of developing some neuropsychiatric conditions changed within the adults themselves and also with respect to children.
For one thing, adults younger than 64 were at higher risk of brain fog or muscle ailments compared to those in the same age range who had other respiratory infections.
In the oldest, a higher incidence of brain fog, dementia and psychotic disorder was seen compared to the control group.
As for children, although the risk of neuropsychiatric diagnoses was lower than in adults, they were more likely to suffer from a psychotic disorder or seizures in the two years after the detection of covid.
"Children are three times more likely to develop psychotic disorders and are twice as likely to develop epilepsy or seizures," Taquet explained.
Even so, he clarified, the absolute risk was very low because the incidence of these ailments in the child population is negligible: for example, for psychotic disorders, the incidence was 0.18% after two years of covid compared to 0.063 % in the control group with other respiratory infections.
Regarding anxiety and mood disorders, the minors did not have a higher risk at any stage after passing the covid compared to the children who suffered other respiratory infections.
The mental fog, Taquet has added, was also "transient" and did not increase after two years.
This research refines a little more on the risks of developing certain ailments, but also leaves other questions still to be resolved.
For example, why it happens.
In children, the experts hypothesize, "the sequelae could be driven, in part, by a postinfectious immune-mediated mechanism, such as acute disseminated encephalomyelitis, as suggested in a prospective study of 52 children hospitalized with covid."
This supports, they explain, their observations "of an increased risk of encephalitis only in children and a higher rate of post-Covid epilepsy or seizures in children."
Across the entire cohort, the persistence of long-term risk for cognitive deficits, dementia, psychotic disorder, epilepsy, and seizures, the researchers add, "suggests that any underlying mechanisms must be at work long after acute infection."
Likewise, they weigh that the short-term disappearance of the added risk of anxiety in the case of children, or that it does not even exist, may be due to the fact that covid “precipitates mood and anxiety disorders in people with an underlying predisposition, through short-lived stress-related pathogenesis to which children are less susceptible.”
The weight of the variants
The researchers also found variations in the risk patterns for these diseases according to the evolution of the main covid variants: right after the appearance of the delta variant, they saw more risk of ischemic stroke, epilepsy or seizures, cognitive deficit, insomnia and anxiety disorders than before it appeared, all compounded by a higher mortality rate.
With omicron, although there was a lower rate of mortality before the appearance of this variant, the risks of neuropsychiatric outcomes remained similar.
“The observation of comparable neurological and psychiatric risks just after (compared to just before) the appearance of the omicron variant suggests an ongoing neuropsychiatric burden of covid,
For Josep Maria Tormos, head of Research at the Institut Guttman, a health center specializing in neurorehabilitation, the research is "super innovative" and reveals what they already suspected: "an increase in psychiatric and neurological diseases" after covid, points out the expert, who has not participated in the study.
“Today we know that some degenerative diseases and psychotic disorders are affected by inflammatory components.
We would therefore be seeing the secondary effect of having been exposed to a systemic inflammatory level and how this influences the development or unmasking of processes that perhaps already existed in a latent way”.
The toll of Covid on our mental health
Ana Rodríguez, a neurologist at the Hospital del Mar in Barcelona, urges caution with the data: “One limitation is that they are based on electronic health records and the information may be more biased.
For example, with cognitive impairment, cases of dementia: the question is whether that person already had incipient cognitive impairment before.
That a person is not diagnosed does not mean that he is not sick ”.
The neurologist also points out that “it cannot be said that it is well related to covid”: “It is an association, not a consequence.
The authors themselves say more studies should be done,” she adds.
The researchers acknowledge the limitations of the study: the sample may underrepresent asymptomatic cases, only those infected early in the pandemic had two-year follow-up data, and variants were not genotyped individually, among others.
However, the results are "relevant", the authors point out, to prepare and anticipate health policies: "The persistent increase in the risk of cognitive deficit, dementia, psychotic disorders and epilepsy or post-COVID seizures two years after the index infection requires a better provision of services to diagnose and manage these sequelae, and research to understand the mechanisms”, say the researchers in the article.
Tormos agrees, above all, on the need to have a health system with the capacity to respond to all the aspects derived from a pandemic: “What is striking is that if you subject the population to a pandemic, there is an acute impact [the covid] and another subacute, in the medium term, which has an effect in itself: the unmasking of other diseases.
We must develop strategies to support the health of the population to avoid this secondary impact”.
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