Heightened anxiety significantly predicts a decline in body mass index (BMI) in girls and young women with anorexia nervosa, according to new research published in the Journal of Psychiatric Research. This finding suggests that targeting anxiety could be key to improving treatment outcomes for those battling this condition.
Anorexia nervosa, characterized by a severe restriction of food intake and an altered perception of body weight, has long challenged the medical community. Despite numerous treatment approaches, many individuals with anorexia nervosa continue to struggle with residual symptoms or relapse. Recognizing the urgent need for more effective treatments, researchers embarked on a study to uncover factors that might predict and influence the course of this complex disorder.
“Anorexia nervosa is a potentially life-threatening psychiatric disorder that is often difficult to treat,” said study author Jamie D. Feusner, a senior scientist at the Centre for Addiction and Mental Health and director of the Brain, Body, and Perception Research Program at the University of Toronto.
“1/3 to 1/2 or more of patients will relapse after intensive treatment involving weight restoration, but we don’t fully understand what factors are predictive of relapse. In this study we tested what clinical and neurobiological factors are associated with worsening of symptoms after intensive treatment, focusing on factors related to reward and anxiety.”
The study involved a total of 64 female participants, with 33 diagnosed with anorexia nervosa and 31 healthy individuals serving as controls. The participants, aged between 10 and 19, were carefully selected to ensure a focus on early-stage anorexia nervosa patients who had recently undergone intensive treatment. This selection was aimed at understanding factors impacting those less affected by long-term effects of the disorder or immediate starvation.
The researchers employed a range of measures to conduct their study comprehensively. To diagnose and understand the severity of anorexia nervosa and any accompanying mental health conditions, the Mini-International Neuropsychiatric Interview for Children and Adolescents was used. They assessed anxiety through the Hamilton Anxiety Rating Scale and the patient-rated Depression, Anxiety, and Stress Scale. Eating disorder symptoms were measured using the Eating Disorder Examination, and the participants’ developmental stages were gauged using the Peterson Rating Scale for Pubertal Development. The team also recorded the participants’ heights and weights to calculate BMI at seven different time points over six months.
Feusner and his colleagues found that individuals with anorexia nervosa had significantly lower BMI percentiles compared to healthy controls and scored higher on measures assessing eating disorder symptoms and anxiety. Importantly, higher anxiety was linked to decreasing BMI over the follow-up period, highlighting anxiety’s role in the progression of anorexia nervosa.
“Adolescents with anorexia nervosa with high levels of anxiety after intensive treatment are more likely to worsen by losing weight in the subsequent 6-month period,” Feusner told PsyPost. “In addition, if their anxiety worsens over this 6-month period, their eating disorder symptoms also worsen. In sum, untreated anxiety plays a large role in the clinical course of adolescents with anorexia nervosa.”
The researchers also analyzed reaction times during specific tasks in a functional magnetic resonance imaging (fMRI) setting to understand reward-related behavior. But they found no association with changes in BMI or eating disorder symptoms. This suggests that while reward-related processes are crucial in anorexia nervosa, they might not directly influence the course of the disorder in the short term.
Similarly, when examining specific brain regions and their connectivity, these neural aspects did not significantly predict changes in BMI or eating disorder symptoms, indicating that the relationship between brain function and anorexia nervosa might be more complex than initially thought.
While these findings are significant, the study is not without limitations. The relatively small sample size is a key constraint, emphasizing the need for larger-scale studies to validate and expand upon these findings. Additionally, the potential influence of medications like selective serotonin reuptake inhibitors, commonly used by the participants, on reward processing and threat perception could not be ruled out. This factor could have affected the study’s outcomes and the predictive accuracy of the models used.
“The major caveats are that the sample size in this study was relatively small (n=33),” Feusner said. “Also, it was limited to girls with restricting-type anorexia nervosa so we don’t know if the results apply to boys, those with binge-purge type of anorexia nervosa, or adults. More work needs to be done in other samples and populations.”
Looking ahead, researchers stress the importance of further investigations into the intricate relationship between anxiety and anorexia nervosa. They suggest that future studies should focus on a larger and more diverse participant pool, including different stages of the disorder and variations in treatment types. Such studies could provide more comprehensive insights and aid in the development of more effective, personalized treatment strategies.
“Much of the anxiety in those with anorexia nervosa is tied to an intense fear of weight gain,” Feusner explained. “To reduce the anxiety, many with anorexia nervosa engage in activities to lose weight, thereby leading to relapse. ​In addition, some individuals with anorexia nervosa who have high anxiety may experience a reduction in their anxiety from food restriction .​The results from this study tell us that we must pay more attention to anxiety in patients with anorexia nervosa to understand and target it better.”
The study, “Testing anxiety and reward processing in anorexia nervosa as predictors of longitudinal clinical outcomes“, was authored by M. Derissen, D.-S.A. Majid, R. Tadayonnejad, R. Seiger, M. Strober, and J.D. Feusner.
