Comorbidity in ADHD
1.1. What is comorbidity
Comorbidity refers to mental disorders that coexist (conditionally independently) and typically often occur together.
Comorbid disorders are characterized by the fact that their joint occurrence is supercoincidental. It follows that the respective disorders have at least partly common causes or must be mutually (co-)caused. This opens a view on the possible causes of ADHD.
Mental disorders are very common. Experts estimate a lifetime prevalence of up to 66% for mental disorders. This means that 2/3 of all people suffer from a mental disorder at some point in their lives, with many merely going undetected because those affected do not seek treatment.1
Many of the disorders listed as comorbidities under 2. for children and under 3. for adults arise just as ADHD does
- Purely genetic (frequent)
- By environmental stress alone (quite rare)
- Due to an interaction of genes + environment (frequent)
ADHD is often accompanied by comorbid disorders. Which disorder should be treated first is likely to be determined by the degree of distress.
1.2. Comorbidity in ADHD
Children with ADHD are 60-100% likely to suffer from at least one psychopathological comorbidity (e.g., tic disorder, depression, social behavior disorder, and others).23
Among n = 174 ADHD-affected adults studied, an average of 1.4 comorbidities were found.4
Among 575 ADHD-affected adults, one study found 52.4% had at least one comorbidity (32.9% had one, 12.7% had two, 3.8% had three, and 3% had four comorbidities).5
One study found mental health comorbidities in 53.9% of 5,840 ADHD sufferers.6
As a particularly good book on comorbidities in ADHD, Müller et al. recommend:7
Jules Angst (2001), persönlicher Brief an H. Hinterhuber, aus P. Hofmann (Hrsg.) (2002): Dysthymie. Anmerkung: Prof. Dr. Jules Angst von der Psychiatrischen Universitätsklinik Zürich gehörte während seiner aktiven Zeit als Arzt und Wissenschaftler zu den international bekanntesten und renommiertesten epidemiologisch tätigen Psychiatern. Seine oben dargestellte Überzeugung wird von vielen Fachkollegen geteilt.“ Zitiert aus Faust, DYSTHYMIE: CHRONISCHE DEPRESSIVE VERSTIMMUNG ↥
Gillberg, Gillberg, Rasmussen, Niklasson (2004): Co-existing disorders in ADHD—Implications for diagnosis and intervention; Article in European Child & Adolescent Psychiatry 13 Suppl 1(S1):I80-92 · February 2004; DOI: 10.1007/s00787-004-1008-4 ↥
Ohnishi, Kobayashi, Yajima, Koyama, Noguchi (2020): Psychiatric Comorbidities in Adult Attention-deficit/Hyperactivity Disorder: Prevalence and Patterns in the Routine Clinical Setting. Innov Clin Neurosci. 2019 Sep 1;16(9-10):11-16. PMID: 32082943; PMCID: PMC7009330. ↥
Slaby, Hain, Abrams, Mentch, Glessner, Sleiman, Hakonarson (2022): An electronic health record (EHR) phenotype algorithm to identify patients with attention deficit hyperactivity disorders (ADHD) and psychiatric comorbidities. J Neurodev Disord. 2022 Jun 11;14(1):37. doi: 10.1186/s11689-022-09447-9. PMID: 35690720; PMCID: PMC9188139. ↥