If there’s a link between asthma and ADHD (and there might be)… I’m on “the A-team”

I was diagnosed with asthma when I was sixteen, and attention deficit hyperactivity disorder (ADHD) when I was 21. The first headline I read about a link between the two diagnoses kind of blew my mind: what connection could my hyperREactive lungs possibly have with my sort of hyperACTIVE and inattentive brain? When I thought for a second, though, I realized that of my many friends with asthma, I know of four or five other people with both asthma and ADHD—and that is just of the people that I personally know (see also, not a scientific sample!)
A study of the overlap between medication prescriptions for ADHD and asthma indicated that there was a 65% greater chance of, reciprocally, someone with a prescription for asthma medicine to provided a prescription for ADHD medication, or vice versa: a person with a prescription for ADHD to develop asthma and require a prescription med for their breathing.1 So, prescription trends indicate a “marked comorbidity”, or chance of developing both, between ADHD and asthma. The strongest link was found in 20-49-year-old women, and 30 to 49-year-old men.1 Now, remember every research methods class ever: correlation does not equal causation. But, it does spark curiosity, no?
I consider both my ADHD and asthma to likely be linked to my prematurity. But, what could other causes be for the connection between asthma and ADHD? Why is there such a link?
2008 research indicates that there may be reason to consider ADHD an “allergic disorder”, or allergic-related disorder.2 If you consider that ADHD is referred to, by the Diagnostic and Statistical Manual of Mental disorders (DSM) as a neurodevelopmental disorder3, this is certainly perplexing. The reason for this association is based on a few things. First, asthma and ADHD are both considered to have a genetic component associated with who develops these conditions, as well as environmental influences on the development of asthma—these are not studied as extensively regarding ADHD, but instead, the writers speculate that the combined environmental and genetic factors, as with—and including—asthma, could “trigger” the development of ADHD.2 For instance, we know that asthma in some individuals is triggered after exposure to pollen, or eating certain foods (an allergic or IgE response—referred to in the article as a hypersensitivity response)—however, the authors consider that exposure to certain “triggers” can, perhaps, have a cascade effect and induce ADHD symptoms2 (or, I would presume, analogous to an asthma exacerbation, an intensification of ADHD symptoms—inability to focus, hyperactivity, impulsivity). It is not only well documented but also well noted anecdotally the worsening of behavioral ADHD symptoms children may have in response to food additives, such as colorings (one study, however, noted that some of these agents improved ADHD symptoms)2,4,5, which could provide further evidence of a “triggering” effect of certain stimuli (allergens or otherwise) on ADHD, similar to what is experienced when people with asthma are exposed to a trigger and experience a worsening in breathing.
It is important to note that the above considerations are only that: considerations or hypotheses.2 Further testing and research into genetics of both ADHD and asthma, immune system changes present in both ADHD and asthma, blood markers (including those for inflammation, also demonstrated to be elevated for those with ADHD6, determining the impacts of environment and diet on both conditions, and evidence of allergic processes in ADHD: this last component would mean that ADHD treatment would, instead of primarily targeting neurotransmitters through medication as is done now through both stimulant and non-stimulant drugs, work on the allergic component of the disorder—if it is indeed true.2 Diet has yet to be a proven strategy for dealing with ADHD or asthma, in absence of a clear allergy or sensitivity, but if the link proves to be correct, could be a cornerstone of future ADHD management like it is in asthma.
More to consider, children with asthma—like children with ADHD—often have more behavioral issues than kids without asthma.6 Could this, perhaps, be ADHD symptoms manifesting… and not actually related to asthma? Both conditions also come with an increased risk of mood and anxiety disorders.6
Now, there is no clear-cut evidence here to say that there is a certain link between ADHD and asthma, and vice versa. However, it is interesting to consider—at least if you have both diagnoses, anyways. I look forward to seeing where research takes this discussion in years to come. Who knows, maybe one day I’ll be able to take one medication to alleviate both my ADHD and asthma symptoms? (Yeah, right! Pipe dreams!)

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