ADHD: co-occurring health conditions

Anxiety is the most common co-occurring health condition with Adult ADHD. Individuals diagnosed with ADHD and anxiety disorders have more severe anxiety symptoms than those without ADHD (Katzman et al, 2017)[1]. We can all be affected by situational anxiety from the stresses of daily life: meeting deadlines, managing relationships, and balancing work and home life causes anxiety for many of us. But for those with ADHD, they are facing all the same stresses while battling time blindness, consistent inconsistency[2], poor memory, and exaggerated emotions. It’s not purely psychological either: the coexistence of ADHD and anxiety is described by both biological as well as psychological models. Studies have also shown that anxiety in ADHD may make working memory worse, and be different from pure anxiety (Gnanavel et al, 2019)[3].

As well as anxiety, a recent study has also considered the link between ADHD and chronic fatigue. The researcher found that the degree of central fatigue and associated changes in tryptophan (a brain chemical) may intensify the severity of symptoms in ADHD - although more studies in adults are needed to confirm this (Yamamoto, 2022)[4]. We know there's a link between the fatigue signal in people who have chronic fatigue and tryptophan in the brain (Castell et al, 1999)[5]. Other studies have shown that adults with ADHD have lower levels of tryptophan (and its metabolites) than neurotypical individuals, suggesting that these are connected with the severity of current ADHD symptoms (Aarsland et al, 2015)[6].

Other studies have also looked at the connections between CFS and ADHD, with fatigue reported as a common symptom of ADHD in adults, although it is not part of the diagnostic criteria. By consulting data from outpatient services, a 2017 study concluded, “Adults with ADHD experience greater fatigue than healthy controls. Adults with CFS and ADHD share many trans-diagnostic clinical characteristics, including difficulties with low mood, anxiety, and reduced self-efficacy, which impact upon their overall functioning” (Rogers et al, 2017)[7].

Additionally, as we’ll discuss later, individuals with ADHD have a higher risk of diabetes and long term medication use leads to higher risk of cardiovascular diseases as well.

Footnotes

  1. Katzman, M. A., Bilkey, T. S., Chokka, P. R., Fallu, A., & Klassen, L. J. (2017). Adult ADHD and comorbid disorders: clinical implications of a dimensional approach. BMC Psychiatry, 17(1), 302

  2. 'Consistent inconsistency' is distrust and uncertainty in one’s self that builds up over years of dealing with the symptoms of ADHD, doubting one’s own ability to accomplish something.

  3. Gnanavel S, Sharma P, Kaushal P, Hussain S. Attention deficit hyperactivity disorder and comorbidity: A review of literature. World J Clin Cases. 2019 Sep 6;7(17):2420-2426

  4. Yamamoto T. The relationship between central fatigue and Attention Deficit/Hyperactivity Disorder of the inattentive type. Neurochem Res. 2022 Sep;47(9):2890-2898.

  5. Castell LM, Yamamoto T, Phoenix J, Newsholme EA (1999) The role of tryptophan in fatigue in diferent conditions of stress. Adv Exp Med Biol 467:697–704.

  6. Aarsland, T.I.M., Landaas, E.T., Hegvik, TA. et al. Serum concentrations of kynurenines in adult patients with attention-deficit hyperactivity disorder (ADHD): a case–control study. Behav Brain Funct 11, 36 (2015).

  7. Rogers DC, Dittner AJ, Rimes KA, Chalder T. Fatigue in an adult attention deficit hyperactivity disorder population: A trans-diagnostic approach. Br J Clin Psychol. 2017 Mar;56(1):33-52.