**3. Post-COVID-19 conditions and mental health**

Of the diverse constellation of symptoms that make up post-COVID-19, some are found in the mental health arena. Neurological and psychiatric symptoms include fatigue, weakness after exertion, cognitive complaints, sensorimotor symptoms, headaches, insomnia, depression, and PTSD [25]. The mechanisms involved in post-COVID-19 development and the factors influencing recovery from COVID-19 are still at an early stage. Current hypotheses include psychological factors, inflammatory and immune responses, and physical deconditioning [26, 27].

Human coronaviruses (including SARS-CoV and MERS-CoV) are one of several groups of viruses thought to be potentially neurotrophic. It has been observed from previous outbreaks that respiratory coronaviruses can penetrate the brain and cerebrospinal fluid, permeating the central nervous system in less than a week, and can then be detected in the cerebrospinal fluid [28]. The perturbation of the immune system caused by the infection could cause psychopathology, and psychiatric consequences have also been observed after previous outbreaks of the coronaviruses. The spread of the pandemic caused by the SARS-CoV-2 virus could be associated with psychiatric implications. Cognitive difficulties are symptomatic features of all psychological disorders [16].

In one cohort study examining the cognitive profile after infection with COVID-19, it was found that 34.3% of patients had cognitive complaints after infection with COVID-19. Patients with headache, anosmia, dysgeusia, diarrhea, and those requiring oxygen therapy had lower scores on subtests of memory, attention, and executive function compared to asymptomatic patients. Patients with headache and clinical hypoxia had lower scores in the global cognitive index, while higher scores in anxiety and depression were found in patients with cognitive complaints. Emotional stress,

#### *Post-COVID-19 and Mental Health DOI: http://dx.doi.org/10.5772/intechopen.110409*

such as anxiety, depression, and insomnia, can play a role in subjective cognitive complaints. These findings emphasize the importance of early detection of anxiety and depression in order to avoid later neuropsychological impairments in patients with COVID-19 [8].

Cognitive impairment with or without fluctuations, including brain fog, which may manifest as difficulty with concentration, memory, receptive language, and/ or executive function, has been observed in patients with COVID-19 [29–31]. Post-COVID brain fog in critically ill patients with COVID-19 may develop from mechanisms such as deconditioning or PTSD. However, reports of COVID-19-induced brain fog following mild COVID-19 illness suggest that dysautonomia may also contribute. Finally, long-term cognitive impairment is well recognized in the post-critical phase of the disease, occurring in 20–40% of patients discharged from intensive care units [31–34].

Numerous studies have been published on mental health of people around the world during the COVID-19 pandemic reporting varying rates of mental health problems. Findings from extensive scientific literature indicate that the outbreak of the COVID-19 pandemic increased the prevalence of mental health problems by a massive 25%, worldwide [35].

A large body of evidence suggests that there is a mixed but significant increase in mental health problems among general population [36–40], but also among other specific populations, such as patients with preexisting chronic health conditions [41–43], patients with preexisting severe mental disorders [44–47], and alcohol addicts [48–50]. Also, an increased prevalence of anxiety and depression symptoms was noted in the population of health-care workers during the pandemic [51], with psychological distress and insomnia [52], as well as physical and mental exhaustion and burnout [53–56].

Individuals with COVID-19 experience a range of psychiatric symptoms that persist or occur months after the initial infection [57].

In a study conducted in Italy on a sample of 402 people who recovered from COVID-19, the psychopathological impact of COVID-19 on survivors was examined taking into account the effect of clinical and inflammatory predictors. It showed that one month after hospitalization, a significant proportion of patients self-rated in the psychopathological range: 28% for PTSD, 31% for depression, 42% for anxiety, 20% for symptoms of obsessive-compulsive disorder (OCD), and 40% for insomnia. Approximately 56% of COVID-19 survivors were positive in at least one of the domains assessed for psychiatric sequelae (PTSD, depression, anxiety, insomnia, and obsessive-compulsive symptomatology). Patients with a previously confirmed psychiatric diagnosis showed increased scores on most psychopathological measures [58].

One systematic review included peer-reviewed studies reporting on neuropsychiatric symptoms at post-acute or later time points after COVID-19 infection and in control groups where available. The total number of subjects was 18,917 patients and the average duration of follow-up after recovery from COVID-19 was 77 days. The quality of the studies was mostly moderate. The most common neuropsychiatric symptom was sleeping disturbance (total prevalence = 27.4%), followed by fatigue (24.4%), objective cognitive impairment (20.2%), anxiety (19.1%), and PTSD (15.7%). Two studies in the review compared COVID-19 patients with controls and found that COVID-19 patients had higher levels of mental health symptoms. Based on hospitalization status, infection severity, or length of follow-up, there was no difference in the prevalence of mental health problems among COVID-19 patients across the studies in the review [59].

There are numerous obstacles in the literature to date regarding the mental health aspects of the post-COVID-19 condition, including the dearth of studies with active control groups for attributing COVID-19 illness symptoms, the lack of consensus on the term "post-COVID-19 condition," and diverse participant selection criteria [60].

In addition to seriously affecting mental health and well-being of people around the world, the COVID-19 pandemic has also raised concerns about increased suicidal behavior. Factors that may increase suicidal risk during a pandemic, especially in vulnerable groups (such as people with a previous history of psychiatric disorder, people over 65, people who have already attempted suicide, COVID-19 frontline health-care workers, people infected with the coronavirus, and people who are recovering from COVID-19, as well as people whose family member or friend died of COVID-19), are social isolation; anxiety; fear of infection; prolonged stress; job insecurity and unemployment; and access to food, education, and health care in the non-COVID system [61, 62].

The few available studies on the mental status of patients with COVID-19 provide us with preliminary information about how psychiatric symptoms associated with COVID-19 develop and change. During the hospital stay, a significantly high proportion of patients reported depression (60.2%), anxiety (55.3%) [63], and PTSD (96.2%) [64]. Liu et al. [65] found that the prevalence rate of clinically significant depression, anxiety, and PTSD symptoms in COVID-19 patients after hospital discharge was 19%, 10.4%, and 12.4%, which is a significant drop compared to the findings of the previously mentioned studies. The adverse effects of COVID-19 on mental health are evident after discharge from hospital, with sleep difficulties highlighted as a central issue. Also, Liu et al. pointed out that perceived discrimination is a central predictor of mental illness and that preventing and addressing the social stigma associated with COVID-19 can be crucial for improving the mental health of recovered patients [65].

High rates of mental health problems, especially anxiety, depression, suicidal behavior, and PTSD, have been reported in general population and after previous coronavirus epidemics, regardless of infectious status [66, 67]. One study conducted in South Korea on a sample of patients quarantined for suspected or confirmed MERS-CoV found that 40% of patients were given a psychiatric diagnosis while in the hospital and that 70.8% of confirmed patients who survived the illness displayed psychiatric symptoms, including hallucinations and psychosis. None of the individuals who had MERS-CoV that was suspected but not yet confirmed displayed any symptoms suggesting a possible viral mechanism underlying psychiatric disorders, a dose-response effect, or a greater psychological effect of receiving a confirmed diagnosis of respiratory disease [68]. A study involving 90 cases with SARS-CoV similarly showed high levels of psychological distress with 59% diagnosed with psychiatric disorders and a continued prevalence of 33% at thirty-month follow-up. The severity of psychological symptoms was found to be related to disease severity and functional impairment [69, 70].

Several long-term health complications in previous coronavirus infections are well documented. A review that included 34 studies and aimed to assess physical and mental health after problems with COVID-19, with a follow-up period longer than one month after discharge or after the onset of symptoms, showed that the most frequently reported mental health problems were anxiety (ranging from 6.5% to 63%), depression (4–31%), and PTSD (12.1–46.9%). Patients and people admitted to critical care noted higher levels of exhaustion, pain, anxiety, and depression. Up to three months following COVID-19, a general decline in quality of life was observed.

Up to three months following COVID-19, various physical and mental health issues were present, according to this review. Findings indicate the necessity of thorough evaluation and rehabilitation following COVID-19 to improve the quality of life [71].

Sleep problems are another prominent post-COVID-19 mental health problem, especially insomnia, which has been observed in both the acute and chronic stages of the disease [24, 72–74]. Other studies have also suggested that sleep problems are a central complication perceived among COVID-19 survivors [65, 75, 76]. Sleep difficulties, anxiety, and depression were present in approximately one-quarter of patients at six-month follow-up after acute COVID-19 in a study conducted in China [77].

Clinically significant depression and anxiety have been reported in approximately 30–40% of patients following COVID-19, similar to patients with previous severe SARS, starting in 2002, and MERS, starting in 2012 [78–81]. Clinically significant PTSD symptoms have been reported in approximately 30% of COVID-19 patients requiring hospitalization and may occur early during acute infection or months later [58, 81].

An analysis of a large-scale data set that included 62,354 patients who survived COVID-19 from 54 health-care organizations in the United States estimated that between days 14 and 90 following diagnosis, there were 18.1% first-time and recurrent cases of psychiatric disorder. More significantly, it revealed that among a subset of 44,759 patients without a history of psychiatric illness, the estimated overall probability of developing a new psychiatric illness within 90 days of a COVID-19 diagnosis was 5.8% (anxiety disorder = 4.7%; mood disorder = 2%; insomnia = 1.9%; dementia (among those under 65 years) = 1.6%). All these values were significantly higher than in the corresponding control cohorts of patients diagnosed with influenza and other respiratory infections. Survivors of COVID-19 appear to be at increased risk for psychiatric sequelae, and a psychiatric diagnosis may be an independent risk factor for COVID-19 [82].

The prevalence of mental health issues varies significantly across studies, which may be a result of variations in the measures used to assess these outcomes as well as regional variations in the influence of cultural or spiritual beliefs on attempts to manage the psychological impact of coronavirus disease [83].

Although higher rates of psychiatric symptoms can be expected in the general population after a pandemic due to exposure to traumatic life events such as death of friends and relatives, loss of income, fear, and general psychological distress, within this group there may also be individuals whose cognitive and psychological disorders are directly related with brain changes caused by the coronavirus. For this reason, the question can be raised as to how the mentioned group will respond to standard treatment, for example, antidepressants, anxiolytics, and cognitive therapies [30].

Treatments such as cognitive-behavioral psychotherapy (CBT) are recommended for various psychiatric manifestations of the post-COVID condition, such as chronic fatigue syndrome [84]. However, face-to-face cognitive-behavioral psychotherapy is a time-intensive treatment and the question is how applicable it is during the pandemic due to various government restrictions that include physical and social distancing to prevent further spread of the virus [85]. Despite this, new modern ways of digital communication can enable effective support in the form of rehabilitation services provided through information and communication technologies, especially in the situation of an infectious disease pandemic and among COVID-19 survivors [86–88]. Computer-based interventions target improvement of physical and emotional functioning in patients with chronic pain and functional somatic syndromes [89]. Internet-delivered cognitive behavioral therapy (I-CBT) has been reported to

be an effective and efficient treatment for psychiatric problems and musculoskeletal symptoms, compared to waiting lists or usual care settings, and may be equivalent to traditional (face-to-face) forms of provision [90–92].

Therefore, telehealth (telerehabilitation and telepsychiatry) could be considered as a follow-up treatment in an effort to prevent long-term physical and mental health complications in post-COVID-19 patients [93].

## **4. Mental health issues in the post-COVID-19 era**

Evidence suggests that there is a significant increase in mental health problems among general population and vulnerable groups. Previous major public health crises have shown that more than half of the population developed mental health problems and needed mental health intervention [94].

In the post-pandemic era, it may be difficult to identify mental disorders etiologically related to COVID-19 (e.g. cytokine storm anxiety) due to the lack of specific diagnostic or screening tools. Due to limited scientific understanding of the link between COVID-19 and mental health so far, post-pandemic preparedness is difficult. Clinicians, researchers, and policymakers are expected to be prepared for these mental health issues in terms of assessment, interventions, and models of care in the post-pandemic era [94].

Given the global scale of the pandemic, it is clear that health-care needs for patients affected by the effects of COVID-19 will continue to grow for the foreseeable future. Meeting this challenge will require leveraging existing and developing new health-care models and interdisciplinary collaboration to improve both the physical and mental health of COVID-19 survivors in the long term [95].

Data reporting mental health consequences of coronavirus infection, especially long-term, are needed to improve treatment, mental health-care planning, and preventive measures during the COVID-19 pandemic. It is necessary to conduct active medical monitoring of patients post-COVID-19, and since post-COVID-19 physical and mental health problems that can reduce the quality of life can persist for three months or longer after the illness, early examination and comprehensive planning of rehabilitation of patients may be needed to effectively prevent and manage post-COVID-19 complications, which could reduce economic and clinical health consequences and prevent long-term disability [96].
