1. Dear Editor
The characteristics of schizophrenia, including delusions, hallucinations, poor insight, cognitive impairment, and disorganized behavior [1] and demographic characteristics including homelessness and living in communal homes [1] have provided the basis for COVID-19 infection in patients with schizophrenia. Due to impairments in insight and decision-making capacity, people with schizophrenia are less likely to adhere to protective measures [2].
Medical comorbidity is the norm rather than the exception in schizophrenia. More than 70% of patients with schizophrenia have one or more clinical conditions [3]including chronic pulmonary disease [4], high blood pressure [5], and diabetes type II [6]. In case of the need for hospitalization in care unit admissions, regardless of the cause, they are at greater risk for acute organ dysfunction [7]. It is also estimated that smoking in patients with schizophrenia is 40% to 90% [8], which can increase the risk of progression and severe complications of COVID-19 infection [9]. On the other hand, social distancing, which is an important measure to control COVID-19, has added an additional toll on schizophrenic patients [10] because individuals with schizophrenia have smaller and poorer-quality social networks than the general population [11]. Also, coronavirus infection may aggravate the psychotic symptoms [12] and even cause symptoms of schizophrenia. The dysregulated immune system is a potential mechanism linking schizophrenia to more severe COVID-19 infection [13, 14, 15]. It has also been reported that clozapine, as the only approved drug resistant to treatment of schizophrenia [16] is associated with an increased risk of COVID-19 infection [17]. This set of factors has made schizophrenia a highly vulnerable and risk group for COVID-19. Accordingly, Bitan et al. showed that people with schizophrenia were twice more likely to be hospitalized due to COVID-19 and three times more likely to experience COVID-19 mortality compared to controls [18]. What makes the situation more critical is that individuals with schizophrenia are less likely to be vaccinated than the general population [19]. Even the effectiveness of vaccination on severe mental illness is questionable [20]. Also, patients with COVID-19 schizophrenia are less likely to be admitted to the intensive care unit due to discrimination [21].
In Iran, many patients with schizophrenia have abandoned their treatments for reasons such as lack of knowledge and understanding of the nature of their disease, fear of COVID-19, lack of adequate infrastructure for telemedicine, and psychological effects of social isolation, which can be very worrying for the health of the community and the creation of subsequent waves. Accordingly, due to the high statistical population of people with schizophrenia, their role in the spread of the COVID-19 epidemic, the disobedience of the protective measures of COVID-19, and the serious consequences of COVID-19 on the health system and the country’s economy, it is necessary for health authorities to take special measures to prevent and treat COVID-19 in patients with schizophrenia. Also, the families of many schizophrenic patients have a socioeconomic vulnerability that has forced them to prioritize budgets for household affairs. Due to the cognitive impairment of people with schizophrenia, this issue has led to tension, destruction, and reduction of interpersonal and family relationships.
2. Conclusion
Due to the limited access and shortage of medicines, including psychiatric medicine in Iran, intensified by US economic sanctions and drastically reduced therapists’ treatment choices, international organizations, including the Red Crescent and the World Health Organization, are requested to take urgent action to provide the needed medicine.
Given that many psychotic patients have abandoned treatment and have doubts about the effectiveness of vaccination, it is recommended that the Ministry of Health of the Islamic Republic of Iran prioritize the treatment of schizophrenic patients to prevent future mutations of the COVID-19 virus.
It should be noted that these patients should be vaccinated with the vaccines that have the highest immunogenicity approved by the World Health Organization.
Since many people with schizophrenia have low socioeconomic status, they refer to public hospitals. It is requested that appropriate infrastructure be provided for telemedicine and e-mental health in public hospitals. Also, financial aid is necessary to provide medicine and the necessities of life.
It is recommended to reopen private mental health clinics and monitor the patients to provide specialized services and reduce patient traffic in public hospitals.

Ethical Considerations
Compliance with ethical guidelines
There were no ethical considerations to be considered in this research.

Funding
This research did not receive any grant from funding agencies in the public, commercial, or non-profit sectors.

Authors' contributions
Conceptualization and Supervision: Mohammad Reza Mousavi; Methodology: Mohammad Reza Mousavi; Investigation, Writing–original draft, and Writing–review & editing: Both authors; Funding acquisition and Resources: Mohammad Reza Mousavi. 

Conflict of interest
The authors declared no conflict of interest. 


References

1. Morgan VA, Waterreus A, Carr V, Castle D, Cohen M, Harvey C, et al. Responding to challenges for people with psychotic illness: Updated evidence from the survey of high impact psychosis. Australian & New Zealand Journal of Psychiatry. 2017; 51(2):124-40. [DOI:10.1177/0004867416679738] [PMID]
2. Larkin A, Hutton P. Systematic review and meta-analysis of factors that help or hinder treatment decision-making capacity in psychosis. The British Journal of Psychiatry. 2017; 211(4):205-15. [DOI:10.1192/bjp.bp.116.193458] [PMID]
3. Carney CP, Jones L, Woolson RF. Medical comorbidity in women and men with schizophrenia. Journal of General Internal Medicine. 2006; 21(11):1133-7. [DOI:10.1111/j.1525-1497.2006.00563.x] [PMID] [PMCID]
4. Zareifopoulos N, Bellou A, Spiropoulou A, Spiropoulos K. Prevalence of comorbid chronic obstructive pulmonary disease in individuals suffering from schizophrenia and bipolar disorder: A systematic review. Journal of Chronic Obstructive Pulmonary Disease. 2018; 15(6):612-20. [DOI:10.1080/15412555.2019.1572730] [PMID]
5. Sugai T, Suzuki Y, Yamazaki M, Shimoda K, Mori T, Ozeki Y, et al. High prevalence of obesity, hypertension, hyperlipidemia, and diabetes mellitus in Japanese outpatients with schizophrenia: A nationwide survey. Plos one. 2016; 11(11):e0166429. [DOI:10.1371/journal.pone.0166429] [PMID] [PMCID]
6. Subramaniam M, Chong SA, Pek E. Diabetes mellitus and impaired glucose tolerance in patients with schizophrenia. The Canadian Journal of Psychiatry. 2003; 48(5):345-7. [DOI:10.1177/070674370304800512] [PMID]
7. Shen HN, Lu CL, Yang HH. Increased risks of acute organ dysfunction and mortality in intensive care unit patients with schizophrenia: A nationwide population-based study. Psychosomatic Medicine. 2011; 73(7):620-6. [DOI:10.1097/PSY.0b013e3182280016] [PMID]
8. Hartz SM, Pato CN, Medeiros H, Cavazos-Rehg P, Sobell JL, Knowles JA, et al. Comorbidity of severe psychotic disorders with measures of substance use. JAMA Psychiatry. 2014; 71(3):248-54. [DOI:10.1001/jamapsychiatry.2013.3726] [PMID] [PMCID]
9. Vardavas CI, Nikitara K. Covid-19 and smoking: A systematic review of the evidence. Tobacco Induced Diseases. 2020; 18:20. [DOI:10.18332/tid/119324]
10. Dennis RA, Caceda R. Why covid-19 is especially difficult for those with schizophrenia: Reasons and solutions. The Primary Care Companion for CNS Disorders. 2020; 22(5):22(5):20com02739. [DOI:10.4088/PCC.20com02739]
11. Degnan A, Berry K, Sweet D, Abel K, Crossley N, Edge D. Social networks and symptomatic and functional outcomes in schizophrenia: A systematic review and meta-analysis. Social Psychiatry and Psychiatric Epidemiology. 2018; 53(9):873-88. [DOI:10.1007/s00127-018-1552-8] [PMID] [PMCID]
12. Severance EG, Dickerson FB, Viscidi RP, Bossis I, Stallings CR, Origoni AE, et al. Coronavirus immunoreactivity in individuals with a recent onset of psychotic symptoms. Schizophrenia Bulletin. 2011; 37(1):101-7. [DOI:10.1093/schbul/sbp052] [PMID] [PMCID]
13. Mehta P, McAuley DF, Brown M, Sanchez E, Tattersall RS, Manson JJ, et al. HLH across specialty collaboration. covid-19: Consider cytokine storm syndromes and immunosuppression. The Lancet. 2020; 395:1033-4. [DOI:10.1016/S0140-6736(20)30628-0]
14. Müller N, Weidinger E, Leitner B, Schwarz MJ. The role of inflammation in schizophrenia. Frontiers in Neuroscience. 2015; 9:372. [DOI:10.3389/fnins.2015.00372]
15. Zhou Z, Kang H, Li S, Zhao X. Understanding the neurotropic characteristics of SARS-CoV-2: From neurological manifestations of covid-19 to potential neurotropic mechanisms. Journal of Neurology. 2020; 67:2179-84. [DOI:10.1007/s00415-020-09929-7] [PMID] [PMCID]
16. Martini F, Spangaro M, Buonocore M, Bechi M, Cocchi F, Guglielmino C, et al. Clozapine tolerability in treatment resistant schizophrenia: Exploring the role of sex. Psychiatry Research. 2021; 297:113698. [DOI:10.1016/j.psychres.2020.113698] [PMID]
17. Govind R, De Freitas DF, Pritchard M, Hayes RD, MacCabe JH. Clozapine treatment and risk of covid-19 infection: Retrospective cohort study. The British Journal of Psychiatry. 2021; 219(1):368-74. [DOI:10.1192/bjp.2020.151] [PMID] [PMCID]
18. Bitan DT, Krieger I, Kridin K, Komantscher D, Scheinman Y, Weinstein O, et al. Covid-19 prevalence and mortality among schizophrenia patients: A large-scale retrospective cohort study. Schizophrenia Bulletin. 2021; 47(5):1211–7. [DOI:10.1093/schbul/sbab012] [PMCID]
19. Bitan DT. Patients with schizophrenia are under‐vaccinated for covid‐19: A report from Israel. World Psychiatry. 2021; 20(2):300-1. [DOI:10.1002/wps.20874] [PMID] [PMCID]
20. Mazereel V, Van Assche K, Detraux J, De Hert M. Covid-19 vaccination for people with severe mental illness: Why, what, and how? The Lancet Psychiatry. 2021; 8(5):444-50. [DOI:10.1016/S2215-0366(20)30564-2]
21. Fond G, Pauly V, Leone M, Llorca PM, Orleans V, Loundou A, et al. Disparities in intensive care unit admission and mortality among patients with schizophrenia and covid-19: A national cohort study. Schizophrenia Bulletin. 2021; 47(3):624-34. [DOI:10.1093/schbul/sbaa158] [PMID] [PMCID]