Infections and anxiety and depression: a population-based matched cohort study

Abstract Background Each year, one in four UK adults experience common mental disorders (CMD), (i.e., anxiety or depression). While central nervous system infections are associated with an increased CMD risk, the relationship between infections at other sites and CMDs is unclear. Methods We conducted six matched cohort studies using data from the Clinical Practice Research Datalink Aurum (01/01/2007-31/03/2023). Adults with lower respiratory tract (LRTI), urinary tract (UTI) and skin/soft tissue (SSTI) infections, gastroenteritis (GE), sepsis, and meningitis/encephalitis (positive control) were matched on sex, age, general practice, and calendar period with up to five adults without that infection. We used Cox regression, stratified by matched set, adjusted for Charlson comorbidity index, alcohol, smoking, and body mass index to estimate hazard ratios (HRs) for incident CMD comparing adults with and without infection. Results Numbers of included individuals ranged from the smallest cohort of 12,758 with meningitis/encephalitis matched to 72,265 without, to the largest cohort of 303,425 with SSTI matched to 1,616,755 without. Median follow-up ranged from 3.9 in the sepsis cohort to 5.9 years in the LRTI cohort. Median age ranged from 43 (IQR 30,61) in the meningitis/encephalitis cohort to 74 (IQR 61,83) in the sepsis cohort; 46-55% of all cohorts were female, except for the UTI cohort (78%). After adjustment, each infection was associated with an increased CMD risk, ranging from HR 1.25 [95%CI1.24,1.26] for SSTI to HR 1.60 [95%CI1.56,1.63] for sepsis. Conclusions Our findings suggest adults with acute infections may be at greater risk of CMDs than adults without infection. Evidence was stronger for more severe infections, e.g. sepsis. Mental health screening and intervention following infections, active control of inflammation during infection, and vaccination, may improve mental health. Key messages • A large study using electronic health records of adults in the UK links acute infections to depression and anxiety, with stronger evidence for more severe infections such as sepsis. • Vaccination and mental health screening and interventions for those with infections, especially severe infections, may benefit mental health.