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  3. ADHD
  4. /
  5. Resources
  6. /
  7. Diagnosing ADHD
  8. /
  9. Other conditions

Other conditions

ADHD is a brain-based disorder the symptoms of which are associated with the chemistry of the brain not functioning as it should. Because brain measures are not useful for diagnosing ADHD, it is assessed primarily through a life history of behaviour during a clinical diagnostic interview.

While the diagnostic criteria for ADHD call for very specific observations, other conditions can result in similar behaviours as exhibited by people with ADHD. During initial diagnosis, the healthcare team will work to isolate the root cause of observed behaviours, and aim to establish whether they are best accounted for by ADHD, by another look-alike condition, or whether one or more other conditions may be present as well as ADHD. When other conditions co-exist with a primary Attention Disorder, they exacerbate the symptoms of and complicate the diagnosis and treatment of ADHD, and in many cases necessitate a referral to a sub-specialist such as a psychiatrist, psychologist or paediatric neurologist, if they are not already part of the diagnosing team.

Possibilities to consider:

  • Thyroid problems
  • Lead poisoning
  • Sleep disorders
  • Anxiety disorders
  • Learning disabilities
  • Issues related to poverty
  • Hunger
  • Family instability
  • Immaturity
  • A middle ear infection or other hearing problems
  • Problems with vision
  • Seizures
  • A reaction to a trauma or major change, like a divorce or major loss in the family
  • Depression, anxiety, or other mental health issues
  • Any other medical condition that could affect behaviour

What kinds of non-psychiatric medical problems commonly occur among people with ADHD?

A relatively new area of research into ADHD is examining what types of medical problems are more common than expected among people with ADHD. As you read this section, keep in mind that not all people with ADHD will suffer from any of these disorders.

Obesity

  1. A Swedish national register study of over 2.5 million people found ADHD patients had a threefold greater risk of obesity relative to their non-ADHD siblings and cousins. It also found a familial co-aggregation of ADHD and clinical obesity, the strength of which varied directly with the degree of genetic relatedness.
  2. A meta-analysis found that compared with typically developing people, children and adolescents with unmedicated ADHD were about 20% more likely to be overweight or obese (15 studies, over 400,000 participants), and adults with unmedicated ADHD almost 50% more likely to be overweight or obese (9 studies, over 45,000 participants). Meta-analyses of twelve studies with over 180,000 participants found that people with unmedicated ADHD were about 40% more likely to be obese, whereas those who were medicated were indistinguishable from typically developing people.

Allergies and asthma

  1. A Swedish national register study of over 1.5 million people found that those with asthma were 45% more likely to have ADHD even after adjustment for relevant variables. A cohort study of almost a million births using the Danish national registers found that children born to asthmatic mothers were 40% more likely to develop ADHD.
  2. In a meta-analysis of six longitudinal studies with over 50,000 participants, those with asthma or atopic eczema were a third more likely to have ADHD than controls. A meta-analysis of three studies with over 48,000 participants found that those with allergic rhinitis were about 50% more likely to have ADHD.

Diabetes Mellitus

  1. A retrospective analysis of over 650,000 children and adolescents in German diagnosis and prescription databases found ADHD was 40% more likely to be diagnosed among children with type 1 diabetes (T1DM).
  2. A German multi-centre registry study of over 56,000 children and adolescents found that those with both ADHD and T1DM suffered twice as often from diabetic ketoacidosis compared with diabetic patients without ADHD. They also found significant differences in HbA1c, and concluded, “Pediatric patients with ADHD and T1DM showed poor metabolic control compared with T1DM patients without ADHD”.
  3. A longitudinal study using the Taiwan National Health Insurance Research Database enrolled over 35,000 patients with ADHD and over 70,000 age- and sex-matched controls. Adolescents and young adults with ADHD were about three times more likely to develop type 2 diabetes mellitus.
  4. A cohort study using multiple Swedish national registers looked at over 1.6 million adults aged 50–64 years. Prevalence of type 2 diabetes mellitus was 70% greater among adults with ADHD.
  5. A meta-analysis found that maternal pre-existing type 1 diabetes was associated with a small increased risk of ADHD in offspring (4 studies, over five million people). So was paternal pre-existing type 1 diabetes (3 studies, 4.7 million people), and maternal pre-existing type 2 diabetes (2 studies, 2.6 million people). A Swedish study looked at all 15,615 children born after their parents were diagnosed with type 1 diabetes. After controlling for confounders, it found that these children had a 30% greater chance of being diagnosed with ADHD.

Other somatic disorders

  1. A meta-analysis of 18 studies with more than 2500 children and adolescents found a moderate association between sleep-disordered breathing and ADHD.
  2. A meta-analysis of sleep in adults with ADHD found no significant differences with normally developing adults, as measured by polysomnography. In four studies with 178 participants, sleep onset latency, stage 1 sleep, stage 2 sleep, slow wave sleep, REM, and sleep efficiency were all comparable. Same with total sleep time (3 studies, 130 persons), and with REM latency and wake after sleep onset (3 studies, 121 persons). As measured by actigraphy, there were no significant differences for time in bed and actual wake time (3 studies, 159 persons) and true sleep (4 studies, 222 persons). However, sleep onset latency was much greater for those with ADHD, and sleep efficiency was moderately lower (4 studies, 222 persons). Nevertheless, subjective evaluations by those with ADHD reported moderately greater difficulty in falling asleep (8 studies, over 1700 persons), moderately greater frequency of night awakenings and moderately lesser likelihood of being rested at wake-up (5 studies, over 1100 persons), and moderately worse sleep quality (5 studies, over 800 persons).
  3. In a Norwegian national registry study of over 1.2 million males and over 1.2 million females, males with ADHD were 30% more likely to be diagnosed with psoriasis, and women with ADHD more than 50% more likely to be diagnosed with psoriasis, than normally developing controls.
  4. A Taiwan nationwide population cohort study of over 8000 people with ADHD and 32,000 matched controls explored associations with autoimmune diseases. It reported that those with ADHD had well over twice the prevalence of ankylosing spondylitis, ulcerative colitis, and autoimmune thyroid disease, and over 50% greater likelihood of asthma, allergic rhinitis, and atopic dermatitis. A Danish national register study of almost a million people found that children with autoimmune disease were 24% more likely to develop ADHD. Maternal autoimmune disease was associated with a 12% greater likelihood of ADHD in their offspring. Paternal autoimmune disease was not associated with any significant effect.
  5. A population-based cohort study of over 900,000 Danish children found that epilepsy was associated with a 2.7-fold increased risk for ADHD. Another population-based cohort study, of over 12,000 Taiwanese, reported that epilepsy was associated with a 2.5-fold increased risk for ADHD. Conversely, a linked cohort study of over 18,000 Taiwanese found ADHD was associated with a fourfold increase in epilepsy. A countrywide registry study of 1.9 million Swedes reported that those with epilepsy were three and a half times more likely to have ADHD. The risk of having ADHD was 85% greater if the person’s mother had epilepsy, 50–60% greater if the father or a brother or sister did, 15% greater for cousins. Genetics explained 40% of the variance, with non-shared environmental factors explaining another 50%.
  6. A longitudinal study using the Taiwan Health Insurance Research Database compared almost 18,000 adolescents and young adults with ADHD with over 70,000 age- and sex-matched controls. Those with ADHD were over three times more likely to develop STIs, after adjusting for demographic data, other psychiatric disorders, and ADHD medications.
  7. A Danish national register cohort study of 1.1 million people found that hospitalisation for serious infections was associated with a subsequent doubling in the rate of ADHD diagnosis. Among those treated with anti-infective agents, the risk of subsequent diagnosis with ADHD was halved.
  8. Using Taiwan’s nationwide population-based dataset, over 116,000 children with ADHD were compared with the same number of randomly selected children without ADHD. Those with ADHD were much more likely to have significant abnormalities of the eye: almost 90% more likely to have amblyopia (“lazy eye”), over 80% more likely to have astigmatism, and twice as likely to have heterotropia, in which the eyes diverge at rest. A study using the same database matched 6817 youths diagnosed with amblyopia to over 27,000 age- and sex-matched controls. Those in the amblyopia group had 1.8 times the risk of developing ADHD.
  9. In a study of over 2.5 million German youth, those with ADHD were nine times more likely to have metabolic disorders, five times more likely to develop viral pneumonia, four times more likely to have white blood cell disorders, three times more likely to have kidney failure, high blood pressure, or be obese, two and a half times more likely to have type 2 diabetes or migraines, twice as likely to have asthma or atopic dermatitis, and 50% more likely to have glaucoma. A Brazilian population-based study including 5671 children found those with migraine about four times more likely to have ADHD.
  10. A nationwide population cohort study using the Swedish national registers compared over 19,000 children with a diagnosis of biopsy-verified celiac disease with over 95,000 matched child controls. It found a subsequent 29% increased risk of ADHD in the celiac patients, rising to 39% when restricting to adult diagnoses of ADHD. However, when comparing 13,000 children diagnosed with celiac disease to their 18,000 non-celiac siblings, the increases became nonsignificant, suggesting the increases were primarily attributable to confounders.

Sources

  1. International Consensus Statement on ADHD