How does the diagnosis rate of mental health disorders after COVID-19 compare to that of other respiratory infections?
The COVID-19 pandemic may have impacted our health in more ways than we realize.
Anywhere from 20-70% of persons who recover from acute COVID-19 infection can develop long COVID, prolonged symptoms that can be so detrimental to physical health that some sufferers are unable to complete even basic daily tasks. Even individuals who never contracted COVID-19 may have felt the mental health ramifications of prolonged isolation during quarantine or losing a loved one to the disease.
Despite being a respiratory virus, COVID-19 can affect multiple organs of the body, including the brain. Indeed, long COVID patients have a high prevalence of persistent neuropsychiatric symptoms after infection. However, it is unclear whether COVID-19 affects the brain similarly to other infections of comparable severity.
An original investigation, recently published in JAMA Psychiatry, estimated the risk of mental disorders and use of psychotropic medication among individuals with COVID-19 compared to persons not tested, persons who tested negative for COVID-19, and persons hospitalized for infections other than COVID-19.
The goal of the cohort study was to determine the subsequent risk of mental disorders among individuals with COVID-19, and whether these associations were specific to COVID-19.
The study included the total adult population of Denmark, comprising all COVID-19 polymerase chain reaction tests. The investigators used Danish registries to identify 4152792 individuals who were alive, at least 18 years of age, and living in Denmark between January 1-March 1, 2020. After excluding individuals with a history of mental disorder, the final analyses included 616546 persons, with follow-up continuing through December 31, 2021.
The investigators defined mental disorders according to the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision. They estimated the risk of new-onset mental disorders and redeemed psychotropic medication through survival analysis using a Cox proportional hazards model with a hierarchical time-varying exposure. All results were adjusted for age, sex, parental history of mental illness, Charlson Comorbidity Index, education level, job status, and income.
In the Danish population, 526749 tested positive for COVID-19 (averaging 50.2% male and 41.2 years of age), 3124933 tested negative (averaging 50.6% female and 49.4 years of age), and 501110 had no tests performed (averaging 54.6% male and 60.7 years of age). The average follow-up time was 1.83 years for 93.4% of the study population.
Compared to individuals never tested for COVID-19, the risk of newly onset mental disorders was increased in persons who tested either positive or negative for COVID-19. Compared to individuals who were negative for COVID-19, the risk of new mental health diagnoses in COVID-19—positive individuals was lower in the group aged 18-29 years, while COVID-19—positive individuals 70 years and older had an increased risk of new-onset mental disorders.
This age-based correlation was similar for psychotropic medicine use, as COVID-19—positive persons aged 18-29 years had a decreased risk while those 70 years and older had an increased risk. Additionally, the risk of new-onset mental disorders was significantly higher in hospitalized COVID-19 patients than in the general population. However, the study authors noted, this difference was not significant when compared to new diagnoses in patients hospitalized for non-COVID-19 respiratory tract infections.
This Danish cohort study found the overall risk of new-onset mental disorders in individuals who tested positive for COVID-19 was not higher than in those who tested negative for COVID-19, with the exception of COVID-19—positive individuals aged 70 years and older. “Future studies should include even longer follow-up time and preferentially include immunological biomarkers,” recommended the study authors, “to further investigate the impact of infection severity on postinfectious mental disorder sequelae.”