Attention Deficit Hyperactivity Disorder & Eating Disorders: Is There a Link?

Attention deficit hyperactivity disorder (ADHD), characterized by inattention, hyperactivity, and impulsivity, is a common childhood disorder. ADHD can often persist into adolescence and adulthood. The prevalence of ADHD is thought to be between 6-7% among children and adolescents and ~5% among adults (Willcutt, 2012).

Increasingly, evidence from multiple studies has pointed to comorbidity between ADHD and eating disorders (EDs). For example, one study found that young females with ADHD were 5.6 times more likely to develop clinical (i.e., diagnosable according to DSM-5) or subthreshold (i.e., sub-clinical) bulimia nervosa (BN) (Biederman et al., 2007). Another study found that found that 21% of female inpatients at an ED unit had six or more ADHD symptoms (Yates et al., 2009).

However, most previous studies are limited by the fact that they assessed comorbidity between ADHD and EDs among patients. This limits our ability to generalize these findings to community samples, where many may experience symptoms of the disorders at subthreshold levels. Moreover, most studies focused on bingeing/purging behaviours and did not investigate differences between ADHD subtypes.

In the current study, Jennifer Bleck and colleagues sought to expand upon a previous study (published in 2013) and address the following questions:

  1. Do clinical/subclinical ADHD and clinical/subclinical EDs co-occur in a nationally representative sample?
  2. Does the relationship differ by type of disordered eating behavior and or ADHD subtype?

Using data from the National Longitudinal Study of Adolescent Health, Bleck et al. analysed data from 12,262 participants (51% females). EDs were assessed when participants ranged from 18 to 27 years (average age was 21.8 years).  The majority of participants were Caucasian (67%), 15% were African-American, 11% were Hispanic, and 4% were Asian.

SUMMARY OF MAIN RESULTS

Clinical Disorders

  • 5.5% reported having been told by a health care provider that they had ADHD
  • 2.1% reported having been told that they have an ED

Subthreshold Disorders

Among those who were not told they had an ED or ADHD (i.e., excluding the above 827 participants):

ADHD:

  • 3.9% reported inattentive ADHD behaviours
  • 8.5% reported hyperactive/impulsive ADHD behaviours

Eating Disorders:

  • 7.1% reported bingeing and/or purging behaviours
  • 14.3% reported restricting behaviours

WHAT ABOUT COMORBIDITY BETWEEN ADHD and EDs?

Bleck and colleagues found that 4.2% of those who reported clinical ADHD also reported clinical EDs, compared to 2.0% of those without ADHD. Overall, those with clinically diagnosed ADHD were ~4 times more likely to engage in clinical-level restrictive and bingeing and/or purging behaviours.

Among those who reported ADHD behaviours but were not diagnosed with ADHD, between 10.6-11.7% also reported subthreshold bingeing and/or purging behaviours, compared to ~6-7% among those without ADHD symptoms. Conversely, there were no differences in subthreshold restrictive eating behaviours between those with subthreshold ADHD and those without. There were no differences between inattentive and hyperactive/impulsive ADHD subtypes.

The image below summarizes the main findings:

Bleck - 2014 - Figure 1

To summarize,

Findings from the current study suggest that those with clinical ADHD are more likely to experience (a) clinical EDs, (b) clinical-level binge and/or purge eating behaviors, and (c) clinical- level restrictive eating behaviors. On the other hand, those with subclinical ADHD are more likely to experience subclinical binge and/or purge eating behaviors while there was no evidence to suggest a relationship between subclinical ADHD and subclinical restrictive behavior.

WHAT DO THESE FINDINGS MEAN?

Since this was a cross-sectional study, we can’t make any conclusions about the nature of the relationship between ADHD and EDs. Thus far, we just know that there’s an association. There are, however, theories about how the two may be linked:

One theory states that the poor planning and difficulty monitoring one’s behavior manifestations of ADHD may lead to overeating, while another states that ADHD patients may be inattentive to internal signs of hunger and forget to eat when engaging in interesting activities leading to binge eating when less stimulated. An alternative explanation suggests that binge eating is a compensatory mechanism to help control the frustration associated with attention and organizational difficulties.

Not knowing much about ADHD, it is difficult for me to assess how plausible those theories sound. Although, to me, they sound a bit too simplistic. Importantly, the aforementioned theories are not mutually exclusive — it could very well be that all three (or more!) possible causes lead to disordered eating behaviours among individuals with ADHD.

LIMITATIONS

As always, the results must be interpreted with the study’s limitations in mind. Here are the main two:

  1. All disordered eating behaviours were self-reported and retrospective. Moreover, participants were asked to report on disordered eating behaviours within the previous week only, likely undercounting the amount of individuals engaging in those behaviours.
  2. An individual was categorized as having clinical-level ADHD if he/she reported being told by a health professional that he/she had ADHD, but the questionnaire did not assess who made the diagnosis and how the diagnosis was made (i.e., was it made using appropriate procedures). (A similar issue is true for the way individuals with clinical-level EDs were categorized as well).

TAKE-HOME MESSAGE FOR CLINICIANS & PARENTS

As findings from this paper suggest, a substantial portion of individuals with clinical-level and subthreshold ADHD exhibit disordered eating behaviours. Consequently, clinicians and parents should be aware of the increased prevalence of clinical and sub-clinical eating disorders among individuals with ADHD, especially bingeing and/or purging, and be particularly vigilant about assessing and/or monitoring children and adolescents diagnosed with ADHD for disordered eating behaviours.

For those of you with ADHD and EDs, what do you think of the findings and what do you think may be behind the association between ADHD and EDs? How do you feel your ADHD and ED relate and/or interact, if at all?

References

Bleck, J., DeBate, R., & Olivardia, R. (2014). The Comorbidity of ADHD and Eating Disorders in a Nationally Representative Sample The Journal of Behavioral Health Services & Research DOI: 10.1007/s11414-014-9422-y

Tetyana

Tetyana is the creator and manager of the blog.

10 Comments

  1. All three of the theories mentioned probably manifest in different people’s cases. They are all conclusions I and other people with ADD/ADHD I know have drawn at one point or another, though.

    I have ADD Inattentive, had diagnosed clinical Anorexia Nervosa multiple times and some periods of binge/purging although always accompanied with restriction and exercise. It may have been the ED alone which contributed to wonky hunger signals but it’s possible the ADD had an effect also. When I was younger I never really felt “full” until I was physically stuffed, and never felt very truly hungry unless I hadn’t eaten for almost 2 days or something. Desire to eat was mostly a pleasure/boredom thing. When I was engaged in a new video game I would just forget to eat the whole day or longer.

    Making rash decisions and indecisiveness is a common issue for people with ADD which could definitely lead to binge/purge behaviors.

    And yeah, the emotional eating or restricting could be used to cope with frustrations over those struggles. One girl I knew with ADHD had Bulimia, and for her I think she said it was mainly an issue of impulse control and using food to cope.

    Having ADD for me I think played a big part in my developing a perfectionist/neurotic personality, because people expect a lot from you because you hyper-focus and can show promising talent in things but then don’t have the ‘discipline’ to keep up your ‘gifts’ and it becomes very frustrating not to be able to perform under pressure. You can’t meet even your own projected goals. Diet and exercise can easily become an arena you try your hand at or hyper-focus in. Perfectionism in AN obviously has been linked before.

    But yeah. That’s just my experience, and again I have heard from other girls with ADD that they also struggle with EDs.

    I think it’s interesting how problems associated with ADD could maybe contribute to ED behaviors on both ends of the spectrum. Definitely one of the potential co-morbidites I hope gets more analysis!

    • Hi katherine i can relate exactly to what you wrote there. Hope you are coping better now.

    • Hi Katherine,

      Thanks for your comment. I agree that all three theories probably hold true to varying extents for different people.

      You wrote, “When I was engaged in a new video game I would just forget to eat the whole day or longer” and I am curious if you think that’s due to ADD and what effect do you feel it had on the ED? Would you binge or overeat after?

      “Having ADD for me I think played a big part in my developing a perfectionist/neurotic personality, because people expect a lot from you because you hyper-focus and can show promising talent in things but then don’t have the ‘discipline’ to keep up your ‘gifts’ and it becomes very frustrating not to be able to perform under pressure. You can’t meet even your own projected goals. Diet and exercise can easily become an arena you try your hand at or hyper-focus in.”

      That’s very interesting. Thanks for writing this; I never thought about it from this perspective but it makes perfect sense.

      If it is repeated, I am curious to find out why both restrictive and bingeing and/or purging behaviours are associated with clinical-level ADHD whereas only bingeing and/or purging (but not restricting) is associated with subthreshold ADHD. I wonder what might be happening there, assuming this finding holds up in future studies. Do you have any ideas?

      • Yeah, I don’t really know (about the forgetting to eat thing)! I feel like forgetting meals because I was getting more instant gratification from games was an ADD thing, but the fact that I’ve never really had strong hunger signals was and ED thing? And so they play off each other.
        I’m not sure about over-eating afterwards. I don’t think so. I just generally ate “a lot” as a kid because I loved food and played a lot. I never experienced “binge” feelings, like loss of control or force-feeding or any of that until I was older and had started deliberately dieting.

        And yeah, that difference between the clinical and sub-threshold is really interesting to me.
        To hazard a guess, it might come back to the matter of impulse control and perfectionism? (But I’m not sure, do sub-threshold ADHD and clinical-level ADHD have different traits, or just symptom severity?)
        Maybe both levels would have a propensity toward binge/purge behavior but restriction comes in with more intense struggles with self worth and perfectionism and everything?
        I hope more people comment with their experiences since I have a very limited perspective.

        Oh, another thought. Many go-to medications for ADD/ADHD are stimulants, which suppress appetite. I wonder how many people in the study were on stimulants or not.

        I’m also curious about biological links. I know there is a correlation between AN and Trichotillomania (and OCD in general) and I hear Trich/Derma/OCDs are common among those with ADHD. I also read a few places that females with ADHD metabolize glucose slower than the average person? Which I think occurs in AN but not sure if that’s in general or only during active restriction.
        (Sorry for rambling.)

        • I don’t know if not having strong hungers is an ED thing, actually, as it seems less psychological and more physiological, if that makes sense. (Fuzzy lines though.)

          I also hope more people comment with their thoughts, as it is quite interesting to think about. I don’t have any personal experiences with ADD/ADHD, so this is quite informative for me.

          “To hazard a guess, it might come back to the matter of impulse control and perfectionism? (But I’m not sure, do sub-threshold ADHD and clinical-level ADHD have different traits, or just symptom severity?) Maybe both levels would have a propensity toward binge/purge behavior but restriction comes in with more intense struggles with self worth and perfectionism and everything?”

          This is actually what I was thinking too. I am totally guessing, of course, but that’s what came to mind as a possible explanation. With regard to subthreshold, this is how it was defined in the study:

          “Participants were considered to have subclinical ADHD if they reported the presence of at least six* ADHD symptoms and had never been told by a health care professional that they had ADHD, thus meeting the symptomology requirement for a diagnosis but not all criteria (e.g., duration, level of impairment).”

          With regard to medications, the authors actually addressed this:

          “Additionally, findings from the current study help to clarify the association between ADHD and
          restrictive eating behavior. Results reveal that diagnosed ADHD is associated with restriction while
          the association did not exist with regard to subclinical ADHD. One explanation may be the role of
          ADHD psychostimulant medications. As the data did not assess the proportion of clinical ADHD
          cases that were using medication at the time the restrictive behaviors were reported, the current
          study is unable to determine the influence of these medications on the relationship. If an ADHD
          patient is using a psychostimulant medication to control their ADHD symptoms and experiences
          the side effect of loss of appetite, they may be more likely to report fasting or skipped meals.
          However, the data assessed behaviors regarding fasting and skipped meals specifically in order to
          lose weight, reducing the potential bias from skipped meals as a result of medication side effects
          rather than as a result of intentional weight loss. Moreover, past studies have found that just 12 to
          32% of those who meet diagnostic criteria use ADHD medications, further suggesting that the
          potential impact on the results based on the inability to control for psychostimulant medication use
          is very small. Nonetheless, future studies are needed to investigate the role of psychostimulants on
          the association between ADHD and restrictive eating behavior.”

          I’m not sure about glucose metabolism stuff, especially with regard to individuals with ADHD, and I don’t know about comorbidity between OCD and ADHD. I’d have to look into that.

          Again, thanks for your comment!

          • Haha, back again. Another thought. Issues with ADHD and needing instant gratification could add to going for extremes with calorie restriction or exercise.

    • Your experience is quite relatable to mine in so many ways. I would “disappear” into something I was fascinated by and, on the flip side, find myself completely lost and unable to focus on other things. What you said about food is spot on for me. I could eat and eat without realizing I should stop & not really feel hungry for days. Anorexia, for me, was glorious at the time. It was a way to get complete control of something (so I thought). Hunger felt beautiful. I liked the pain of it. It meant control, victory. Now, I have a fear of AN. It’s always lurking, even 30 years later. I’m just so afraid I’ll lose control again.

  2. I just read this article after seeing the discussion on your tumblr. I recently started seeing a new psychiatrist who diagnosed me with ADHD and put me on Adderall. I have been bulimic for 10 years. I have always been really up front about an inability to focus/ concentrate, but I’ve always been a straight-A student, well-behaved, etc so it seems that I’ve kind of flown under the radar. My peers would pull all nighters and sit in front of their books for hours, and I literally would have to get up every 20 minutes and like walk around the house looking for something to do. I would binge and purge in anticipation of a night of studying simply because I had nothing else to do and “wanted” to waste time because I couldn’t imagine sitting still for that long but would feel guilty if I was doing something fun. I was describing my experience to this new woman, and she told me that sometimes that is why it is detected so late in girls/ women but ADD/ADHD can come in all kinds of forms, and it doesn’t really have anything to do with intelligence. Sometimes, it is about having trouble getting activated with doing the laundry and doing the dishes and keeping your house clean, and I just nodded, and I was like “somebody finally gets me,” and it was so validating after all this time to feel heard and not like “well, you obviously are studying plenty because you test well so don’t worry about it” when I’m like “aaaah I’m losing my minddddd.” I still haven’t told anyone, including my parents, about the diagnosis or the meds, simply because I’m pretty sure they wouldn’t believe me, which is unfortunate because it feels really reflective of my internal experience, which is very chaotic. I still suck at taking my meds properly because when I am at work, I get so busy that I don’t have time to eat, drink, go to the bathroom, etc, let alone take meds. It feels like every day, someone is kicking me off the floor (I work in an ICU) like 3 hours after everyone else has gone to lunch and reminding me to take a lunch break. But I appreciate knowing that I am not alone in this, and I appreciated seeing some of the other articles about adult diagnosis of ADD/ADHD in women with eating disorders.

    • I’ve read a few places that women with ADHD are most likely under-diagnosed / are diagnosed way later in life than boys, because we tend to show symptoms under a, comparatively, more well-behaved nature or commitment to schoolwork, etc. And it totally sucks.
      ““well, you obviously are studying plenty because you test well so don’t worry about it” when I’m like “aaaah I’m losing my minddddd.” Yes exactly!! Ugh. So glad that woman you mentioned understood. Also I completely identify with the feeling you described around B/Ping adjunct study time.

  3. I (probably) have ADHD (inattentive type) and a restrictive eating disorder. I think they’re related in that the depression, lack of control over my life, and constantly feeling overwhelmed that resulted from my ADHD led to me trying to deal with that by restricting. Also, restriction helps with being understimulated, restless, and bored: it makes everything fuzzier and quiets my mind, sort of a way of self-medicating my ADHD symptoms

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