The Association between ADHD and Obesity: Intriguing, Progressively More Investigated, but Still Puzzling

Abstract

This narrative review is aimed at presenting the most recent evidence on the association between attention-deficit/hyperactivity disorder (ADHD) and obesity. The review is informed by previous relevant systematic reviews and a search in Pubmed and PsycINFO up to 1 August 2019. Although the association between ADHD and obesity would seem, at first, paradoxical, in the past two decades there has been an increasing number of studies on this topic. The present review shows that there is meta-analytic evidence supporting a significant association between these two conditions, at least in adults. Growing evidence is also being published on the genetic and environmental factors underlying the association. However, the cause–effects paths, as well as the exact mechanisms explaining the association, remain unclear. Additionally, empirical evidence guiding the management/treatment of patients with the two conditions is still limited. Therefore, after almost 20 years from the first report of a link between ADHD and obesity, this association continues to be puzzling.

Global prevalence of obesity, overweight and underweight in children, adolescents and adults with autism spectrum disorder, attention‐deficit hyperactivity disorder: A systematic review and meta‐analysis

“…The cause-effects path underlying the links of obesity and ASD/ADHD remained largely unclear. 141,142 There has been arguing about whether ASD/ADHD contributes to obesity or the opposite.…”

Associations between attention deficit hyperactivity disorder symptoms and eating behaviors in early childhood

“…The mechanisms linking ADHD and problematic eating behaviors and BMI or obesity need further attention and investigation . Twin and siblings studies suggest that there may be a shared genetic association between obesity and ADHD symptoms or executive functions and genome‐wide association studies also show overlap in genetic loci between these two traits .…”

Psychiatric Aspects of Obesity: A Narrative Review of Pathophysiology and Psychopathology

“…Attention deficit and hyperactivity disorder (ADHD) is a common neurodevelopmental divergence characterized by inattention, hyperactivity and impulsivity as the cardinal triad. The association between obesity and ADHD, which has been systematically investigated for several years now, is seemingly critical for a better understanding of the psychopathologic dysfunctions that may drive the development of obesity [73][74][75]. Some authors have challenged the association between obesity and ADHD, but these results seem to be outshone by the overwhelming majority of favorable data [76][77][78].…”

“…Structurally, obesity and ADHD have been hypothesized to share common underlying neurobiological and neuropsychological abnormalities such as dysfunctions in brain reward pathways, emotion regulation processes and executive functions [80]. Adults with ADHD often exhibit unhealthy eating habits and feeding anomalies [75]. For instance, difficulty in planning, as a consequence of inattentiveness, often translates into skipping meals and eating between meals or at inappropriate times (night eating) [81].…”

“…Such affective disposition may explain many phenomenological features of BED patients, namely emotional dysfunction (affective instability and reactivity) and dysregulation (alexithymia, avoidance, suppression, lack of reappraisal), impulsivity and motivational disturbances [72]. Many of these behavioral-affective problems, along with other dysexecutive symptoms, are also part and parcel of ADHD's psychopathology, suggesting that a shortage of executive ("cold executive") and motivational-emotional ("hot executive") resources underlies a major subset of non-normative eating behaviors, in which food intake is subverted by supra-homeostatic, affective-hedonic mechanisms that overpower its fine-tuned, homeostatic-hypothalamic regulation (Figure 2) [75].…”