Are Eating Disorders and ADHD Two Peas in a Pod?

May 27, 2024 - Reading time: 6 minutes
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When it comes to impulsive behaviors, attention deficit/hyperactivity disorder (ADHD) and binge-eating disorders seem to be singing from the same songbook. Like two partners in crime, these conditions often go hand-in-hand, leaving a trail of evidence that has researchers hot on their heels.

ADHD, the poster child for impulsivity and inattention, is no stranger to the world of disordered eating. The binge-eating tendencies that characterize disorders like bulimia nervosa (BN) and the newly minted binge-eating disorder (BED) are often fueled by the same impulsive fire that burns bright in ADHD. The numbers don't lie – studies have found the prevalence of eating disorders in ADHD samples to range up to a staggering 12%.

It's a tangled web, but one that researchers are slowly unraveling. The neurobiological mechanisms behind this dynamic duo are still shrouded in mystery, but the clues point to a shared struggle with impulse control. As one researcher put it, "It's like they're playing a game of tug-of-war with their impulses, and sometimes, those impulses win."

The evidence is mounting, like a stack of damning case files. A 5-year prospective study found that children with the combined type of ADHD demonstrated more bulimia-like eating patterns down the road compared to their non-ADHD counterparts. Another study revealed that a whopping 9% of bulimic inpatients exhibited comorbid ADHD – a figure that screams "pay attention!"

But ADHD and binge-eating disorders don't just share impulsive tendencies; they're also partners in crime when it comes to obesity. Studies have shown that individuals with ADHD are more likely to be overweight or obese, with rates as high as 25% in treatment-seeking obese adults meeting criteria for ADHD. And the reverse is also true – those struggling with their weight are more likely to exhibit ADHD-like symptoms, with up to 50% of overweight youth meeting criteria for the disorder.

It's a vicious cycle, a dance between ADHD, binge-eating, and weight issues, each partner stepping on the other's toes. As one researcher quipped, "It's like a game of musical chairs, and no one wants to be left without a seat."

But the plot thickens. Binge-eating disorder, the new kid on the block, is still shrouded in mystery, but its ties to ADHD are becoming increasingly clear. From community samples to large-scale studies, the evidence is mounting – ADHD and BED are more than just casual acquaintances. One epidemiological study even reported an association between subclinical ADHD and binge-eating disorder behaviors, suggesting that even milder forms of the disorder can pave the way for disordered eating patterns.

And then there's the neuroimaging data, the smoking gun that might just crack the case wide open. Studies have shown that individuals with binge-eating tendencies exhibit brain activity in areas linked to impulse control and reward pathways – the same areas that light up like a Christmas tree in ADHD. It's like they're speaking the same neurological language, each condition influencing the other in a complex dance.

One PET study found increased cerebral blood flow in the frontal and prefrontal brain areas of women with BED when exposed to food stimuli, hinting at a potential role in cognitive control of eating behaviors. Another study using methylphenidate (a stimulant used to treat ADHD) found significant increases in dopamine levels in the caudate nucleus of women with BED compared to those without the disorder. It's a tantalizing clue, suggesting that dopamine transmission in this region may be a key player in both ADHD and binge-eating.

It's a complex dance, a tango between impulsivity, reward, and dysregulated eating patterns. As one researcher remarked, "It's like they're all following the same choreography, but with slightly different steps."

But the story doesn't end there. Researchers are now exploring potential treatments that could target both ADHD and binge-eating behaviors, like a one-two punch. Medications like lisdexamfetamine (LDX) and atomoxetine are showing promise, offering a glimmer of hope for those caught in the crosshairs of these intertwined conditions.

LDX, the first medication approved by the FDA to treat moderate to severe BED in adults, has been shown to decrease the number of binge-eating days per week in doses of 50-70 mg (but not 30 mg) in a recent industry-sponsored trial. In this 11-week study, a remarkable 50% of participants taking 70 mg of LDX daily achieved complete binge-eating cessation over a 4-week period, with a good effect size of 0.83-0.97. What's more, participants also lost around 5-6% of their body weight, a promising sign for those grappling with both binge-eating and weight struggles.

Atomoxetine, a selective norepinephrine reuptake inhibitor approved for ADHD treatment, has also shown potential in reducing binge-eating episodes in adults. While not FDA-approved for this purpose, a small study found that atomoxetine could help target impulsivity in both ADHD and BED through its effects on frontal and prefrontal brain circuitries.

As the curtain falls on this intricate tale, one thing is clear: ADHD and binge-eating disorders are more than just acquaintances; they're partners in crime, bound together by a shared struggle with impulse control and dysregulated behaviors. And as researchers continue to untangle this intricate web, they inch closer to uncovering the secrets that could unlock new treatment avenues for those caught in the crossfire.

In the words of one researcher, "The relationship between ADHD and binge-eating is novel, supported by growing evidence, and worthy of further research. By exploring the neurobehavioral underpinnings of these conditions, we may be able to develop targeted treatments that address the core issues at play, rather than just treating the symptoms."

marcDr. Marc Mandell, MD, Psychiatrist, is a well known expert in the field of psychiatry, bringing a wealth of knowledge and clinical acumen to our team at Renowned for his compassionate and patient-centred approach, Dr. Mandell is unwaveringly dedicated to directly supporting patients living with ADHD.