ADHD, Impulsivity, and Bulimia Nervosa

The existence of distinct links between attention deficit/hyperactivity disorder (ADHD) and bulimia nervosa (BN) is still being debated. Patients with BN commonly have histories of increased impulsive behavior, such as loss of control binge eating and purging (Child Adolesc Psychiatry Clin N Am. 2009; 18:31). And, 40% of BN patients reportedly also have deficits in impulse control in non-eating-related areas of their lives, for example, increased sensation-seeking (Eur Eat Disord Rev. 2009; 17:408). However, thus far no good tally of the frequency of ADHD-like symptoms in patients with BN has been established.

Dr. Jochen Seitz from the University Hospital, Aachen, Germany, and a team of German researchers investigated the possible connection between BN and ADHD in a sample of 57 consecutive normal-weight female patients with BN (age range: 15 to 35 years) from inpatient and outpatient admissions at three university hospitals in Germany (PLOS ONE. 2013; 8:e63891.doi:101371). They also recruited an age-matched control group of 40 women without eating disorders who had normal body mass indexes (BMIs).

The researchers used one ADHD interview and two ADHD questionnaires to diagnose patients and controls. To assess impulsivity and attention, they used the TAP (Testbatterie zur Aufmerksamkeitprufung), a German computer-based battery of tests featuring go/no-go tasks, divided attention, and congruent/incongruent executive functions. The Eating Disorders Inventory II and the Structured Interview for Anorexia and Bulimia were used to confirm the diagnosis and to test the severity of the individual eating disorder. The Beck Depression Inventory and the Structured Clinical Interview for DSM-IV were among other tests administered to both groups.

A history of childhood ADHD was found in 20% of BN patients

Among the patients with BN, the prevalence of former childhood ADHD was 21.0%, compared with 2.5% among the controls. The researchers also found that 10.5% of BN patients scored above the cutoff on all three ADHD measures given, compared to 2.5% of controls. When the researchers evaluated neurocognitive deficit scores in both groups, they found that, in general, patients with BN and childhood ADHD had a tendency toward lower neuropsychological test scores than did those without childhood ADHD, indicating more inattentive and impulse response patterns,.

The researchers also analyzed the relative impact of impulsivity, inattention, and hyperactivity on the severity of eating disorder symptoms. Inattention in adulthood explained most of the variance within the eating pathology for patients with BN—the authors believe theirs is the first study to directly show such a relationship. The authors also pointed out several possible ways in which ADHD and BN may interact. ADHD impulsiveness likely contributes to binge eating and purging; however, they note this is only one possibility. The authors found only a weak correlation between impulsivity measures and BN symptoms. In addition, binge eating/purging subscales were not correlated with impulsivity measures.

Many questions remain, and the authors note that the study was limited because it was cross-sectional and thus they could not make causal or developmental inferences. The findings might also partly reflect the effects of possible previous or concurrent substance abuse, which is common among patients with BN.

The authors suggest that because of the high comorbidity between BN and ADHD, clinicians should screen all BN patients for possible ADHD.