Association of Streptococcal Throat Infection With Mental Disorders: Testing Key Aspects of the PANDAS Hypothesis in a Nationwide Study
Sonja Orlovska 1, Claus Høstrup Vestergaard 2, Bodil Hammer Bech 3, Merete Nordentoft 1, Mogens Vestergaard 2, Michael Eriksen Benros 1
Streptococcal infection has been associated with the development of obsessive-compulsive disorder (OCD) and tic disorders, a concept referred to as pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS). This hypothesis is supported by findings of autoantibodies targeting the basal ganglia in the serum of children with PANDAS compared to controls. However, previous studies have been limited in size, and their results have been conflicting, with some not supporting the PANDAS hypothesis. Therefore, the purpose of this study was to investigate the risk of mental disorders following strep throat infection using the largest population-based cohort study to date, utilizing data from nationwide Danish registers that included more than 1 million children.
The population comprised individuals born between 1996 and 2013, who were followed for up to 17 years. During the study period, 40,435 children received a diagnosis of a mental disorder, with 38.1% of them having a previous positive streptococcal test result. Of the 1,078 individuals diagnosed with OCD, 51.6% had a previous positive streptococcal test, while 2,177 individuals were diagnosed with a tic disorder, with 45.6% having a previous positive strep test result.
Those with a positive strep test result had an 18% higher risk of any mental disorder, a 51% higher risk of OCD, and a 35% higher risk of tic disorder compared to individuals who did not undergo a strep test. Interestingly, individuals with a negative streptococcal test result, likely indicating a non-streptococcal throat infection, also showed an increased risk of mental disorders. The study revealed that those with streptococcal throat infections had the highest risk of all mental disorders, particularly OCD, compared to those with non-streptococcal infections. Although an association was found, the absolute risk of OCD and tic disorders following streptococcal throat infection remains small.
Reference:
Orlovska, S., Vestergaard, C. H., Bech, B. H., Nordentoft, M., Vestergaard, M., & Benros, M. E. (2017). Association of Streptococcal Throat Infection With Mental Disorders: Testing Key Aspects of the PANDAS Hypothesis in a Nationwide Study. JAMA psychiatry, 74(7), 740–746. https://doi.org/10.1001/jamapsychiatry.2017.0995
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