Increased incidence of comorbid diseases in adults with ADHD

According to an analysis of population and multigenerational registries, adults with attention-deficit hyperactivity disorder (ADHD) often have comorbid physical conditions, underscoring the importance of assessing adults with ADHD for comorbid conditions. These results were published in The Lancet Psychiatry.

This study included data from full-sibling and maternal half-sibling pairs born in Sweden between 1932 and 1995 (N = 4,789,799). The diagnoses were obtained from the Swedish national patient registry.

The cohort comprised 51% men, 87% of the couples were full siblings, the mean age difference between the siblings was 5.84 (SD, 4.04) years, and 1.29% were diagnosed with ADHD.

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Adjusted for year of birth and gender, ADHD was associated with all physical diseases except rheumatoid arthritis (all P <0.007). The most strongly associated diseases were alcohol-related liver diseases (odds ratio [OR], 4.70), sleep disorders (OR, 4.62), chronic obstructive pulmonary disease (COPD; OR, 3.24), epilepsy (OR, 2.99), fatty liver (OR, 2.94) and obesity (OR, 2.67).

In broader disease groups, ADHD was most strongly associated with conditions of the nervous system (OR, 3.27), respiratory tract (OR, 2.49), musculoskeletal system (OR, 2.03), and metabolism (OR, 2.02).

Researchers using quantitative genetic analysis of the link between ADHD and nervous system disorders found that genetic factors accounted for 28% and the common environment accounted for 13% of the correlation. In diseases of the respiratory tract, musculoskeletal system and metabolism, the genetic components explained 60 to 69% of the correlations.

It remains unclear what role ADHD drugs can play in these patterns. ADHD drugs were not approved for use in adults in Sweden until 2008. The long-term results of taking ADHD drugs in adulthood and the effects on comorbidities remain unclear.

These results suggest that adults with ADHD are more likely to have coexisting conditions than their full or maternal half-siblings, underscoring the importance of screening people with ADHD for comorbidities. Additional studies are needed to assess the biological mechanism that links ADHD to the respiratory, locomotor, and metabolic systems.

Disclosure: Some authors stated links with biotech, pharmaceutical, and / or device manufacturers. For a full list of the author’s disclosures, see the original reference.


Du Rietz E., Brikell I., Butwicka A, et al. Mapping Phenotypic and Etiological Associations between ADHD and Physical Disease in Adulthood in Sweden: a Genetically Informed Registry Study. Lancet psychiatry. Published online July 6, 2021. doi: 10.1016 / S2215-0366 (21) 00171-1

This article originally appeared on Psychiatry Advisor

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