Association of pre-existing psychiatric disorders with post-COVID-19 prevalence: a cross-sectional study

Speakers

Participants who contracted the novel coronavirus were interviewed using web-based cross-sectional analysis from July to September 2021. The study sample came from the pooled panels of an internet research agency (Rakuten Insight, Inc.), which had approximately 2.2 million panelists in 2019. All participants provided informed consent online during registration. Only participants who answered “yes” to the first question, “Have you ever been infected with COVID-19?” were asked to complete the questionnaire. We excluded participants who completed the questionnaire (n = 7760) who (1) answered the dummy question incorrectly (n = 1195); (2) reported not being infected during the survey (n = 6); (3) gave inconsistent responses on physical symptoms (n = 454); (4) gave unlikely answers about the post-infection period (not within 0-20 months) judging from the confirmation date of the first case of COVID-19 infection in Japan (January 15, 2020)¹⁶ (n=84); (5) responded in the open section, which could not categorize existing questionnaire choices (n = 5); and (6) identified an error in the data (n=1). The organizational chart of participants is shown in Fig. 1. Finally, 6015 individuals (response rate = 77.5%) were included in the analyses. The study was in accordance with the Declaration of Helsinki. All methods were performed in accordance with current guidelines and regulations. Participation was anonymous. A credit point that could be used for internet purchases and cash conversion was provided to participants with an incentive. We have used the term gender according to the SAGER guidelines¹⁷. This study was approved by the Ethics Board of the National Center for Neurology and Psychiatry in Japan (A2021-34).

The measure

Result variables

Post-COVID-19

Post-COVID-19 has been dichotomized into “yes” and “no”. We have identified post-COVID-19 based on the WHO definition². We asked the question, “What symptoms do you have?” Participants could choose multiple responses from the symptom options based on the WHO definition of post-COVID-19. Responses were ranked as “yes” when participants chose one of these physical symptoms that were considered (menstrual and menstrual problems, altered smell, altered taste, blurred vision, chest pain, cough, dizziness, fatigue, [intermittent] fever, gastrointestinal problems [diarrhea, constipation, or acid reflux], headache, muscle aches or spasms or neuralgia, shortness of breath, tachycardia or palpitations, and tinnitus and other hearing problems). Post-COVID-19 participants described in the open section were reviewed by four researchers and assigned the type of symptoms they should apply to.

Exposure variables

Pre-existing psychiatric disorders

Pre-existing psychiatric disorders were categorized by responses to the question: “Have you ever been diagnosed or had any psychiatric problems before the COVID-19 pandemic?” Participants chose multiple responses from the following symptom options: “Nothing”, “Depressive disorder”, “Bipolar disorder”, “Panic attack or panic disorder”, “Anxiety disorder or anxiety-related problems (e.g. , hypersensitivity, worry, fear, obsessive-compulsive symptoms), “Alcohol use disorder or alcohol abuse/dependency”, “Use of illicit substances or non-prescription psychotropic drugs”, “Syndrome of ‘burnout’ and ‘Other’ (with an optional comment field). Pre-existing psychiatric disorders were dichotomized into “yes” and “no” based on the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5)¹⁸. Those who have chosen one of these disorders (depressive disorder, bipolar disorder, panic attack or panic disorder, anxiety disorder or anxiety-related problems [e.g., hypersensitivity, worry, fear, and obsessive–compulsive symptoms]) were classified in the “yes” group pre-existing psychiatric disorders. Those who selected only the options ‘Nothing’, ‘Use of illicit substances or non-prescription psychotropic drugs’ or ‘Burnout syndrome’ were assigned to the ‘no’ pre-existing psychiatric disorder group. We considered ‘use of illicit substances or non-prescription psychotropic drugs’ to not meet the diagnostic criteria for alcohol use disorder without information on duration, amount of use and symptoms. Also, the DSM-5 does not include burnout syndrome. Of those who selected “Other” only, those whose comments in the comments field matched the DSM-5 diagnosis were categorized as “yes” pre-existing psychiatric disorders.

Covariates

Covariates were selected based on previous studies of factors associated with post-COVID19^18,19,20,22 and psychiatric disorders.

Kesler6 (K6)

Psychological distress was measured using K6²³. It consists of six items assessing the frequency of psychological distress that has occurred over the past 30 days. Response choices range from 0 (never) to 4 (always), and the total score ranges from 0 to 24. Total K6 scores were categorized as: no (≤ 4), mild, or moderate (5 –12) and severe (≥ 13).

Generalized Anxiety Disorder-7 (GAD-7)

Anxiety symptom was measured using GAD-7²⁴. It consists of seven items assessing the frequency of anxiety symptoms that have occurred over the past 2 weeks. Response choices range from 0 (not at all) to 3 (almost every day), and the total score ranges from 0 to 21. GAD-7 total scores were categorized as follows: no (≤ 4), mild (5–9), moderate (10–14) and severe (≥ 15).

Other covariates

We measured other covariates as follows: post-infection period (<1 month, ≥1 to <3 months, ≥3 to <6 months, ≥6 to <12 months, or ≥12 months), early COVID-19 dyspnea (yes or no), more than five early symptoms of COVID-19 (yes or no)²¹COVID-19 treatment (no hospitalization, hospitalization without ICU stay or hospitalization with ICU stay), age (20-29, 30-39, 40-49, 50-59 or ≥ 60 years old), sex ( male, female, or other), level of education (high school or below, college [e.g., junior college], or university graduate or higher), professional status (self-employed, permanent job, temporary job, unemployed or student), cohabitation (yes or no) and medical history (yes or no). Responses were categorized as “yes” when participants answered that they had any of the following medical histories during the survey: hypertension, diabetes, asthma, bronchitis or pneumonia, atopic dermatitis, angina pectoris, heart attack heart disease, chronic obstructive pulmonary disease or cancer. .

statistical analyzes

Prevalence ratios (PR) post-COVID-19 were estimated using Poisson regression analysis with robust error variance. We used this model because the post-COVID-19 prevalence is greater than 10% and the odds ratio could overestimate the PRs²⁵. The variance inflation factor (VIF) was used to check for multicollinearity. Most of the VIF values ​​were less than 2, and the model mean VIF was < 2. We entered K6 and occupational status as covariates because we considered these to be important covariates, even though they were greater than 2 (K6: ≥ 13 = 2.18; professional status: independent = 2.28 and permanent job = 2.01). We also estimated the interaction between pre-existing psychiatric disorders and post-infectious periods. We then performed a subgroup analysis by post-infection periods because the interaction between pre-existing psychiatric disorders and post-infection periods was significant. All analyzes were performed using Stata 17.0 (Stata Corp, College Station, TX, USA).