Genetics, Mental Health May Be Risk Factors for Teen Eating Disorders
Genetic predisposition, mental health symptoms, personality traits, substance abuse, and high body mass index (BMI) all are early risk factors for eating disorders in adolescence, a study has determined.
These findings may have clinical implications for preventing and treating disordered eating behaviors, especially among teenagers, the investigators said.
Titled “Association of Genetic and Phenotypic Assessments With Onset of Disordered Eating Behaviors and Comorbid Mental Health Problems Among Adolescents,” the study appeared in the journal JAMA Network Open.
Eating disorders or EDs are psychiatric diseases characterized by so-called disordered eating behaviors (DEBs), such as bingeing, purging, and food restriction or avoidance. Other symptoms include an abnormal fixation on body weight and healthy food. The disorders are more common in young women, with peak onset between the ages of 16 and 19.
Most patients with eating disorders experience milder symptoms before the onset of clinical DEBs. Other psychiatric disorders, including anxiety and attention deficit hyperactivity disorder (ADHD), may coexist with EDs. Identifying factors that increase an individual’s risk of developing an ED can help in prevention, early diagnosis, and targeted treatment.
Here, an international team of researchers sought to identify genetic, behavioral, and mental health risk factors that predispose adolescents to DEBs, defined as dieting, binge eating, and purging. Data from the IMAGEN study of 1,623 healthy adolescents from eight European sites were included in the study. Participants were age 14 at the start of the study, 16 at the first follow-up, and 19 at the second follow-up.
The study included 829 girls (51.1%) and 794 boys. Information about DEBs was available for 1,509 participants at age 14, 1,317 at age 16, and 853 at 19.
A total of 278 adolescents (17.1%) reported binge eating in their lifetime and 334 (20.6%) reported purging. More than one-fifth — 356 or 21.9% — said they had dieted. DEBs were more common in girls than in boys.
The mean BMI of 14-year-olds was 20.9, and a higher BMI was associated with DEBs. BMI at age 14 was associated with dieting at ages 16 and 19, but there was no link with binge eating and purging. In turn, dieting at age 14 was linked to future binge eating.
Mental health disorders were more common in adolescents with DEBs than in those without, the results showed. Depression, generalized anxiety, self-harm, post-traumatic stress disorder, and conduct disorders were associated with all three DEBs. Obsessive-compulsive disorder and social phobia were tied to binge eating and dieting. ADHD and oppositional defiant disorder — characterized by frequent anger, irritability, arguing, defiance, or vindictiveness toward authority figures — were associated with purging.
Adolescents with DEBs were at a significantly higher risk of engaging in substance abuse than were healthy teenagers (controls). Individuals who purged had the highest risk of alcohol and drug use, and of smoking. High levels of neuroticism — characterized as a tendency to experience negative emotions such as sadness, anxiety, and mood swings — and low levels of agreeableness, as associated with lack of empathy and selfishness, were linked to all three DEBs.
Self-harm and conduct problems at age 14 were linked to binge eating and purging at ages 16 or 19. Neuroticism at 14 was associated with binge eating in later adolescence while conduct disorder, drug and alcohol abuse, and low agreeableness were all associated with purging.
Adolescents with low agreeableness and conduct problems at age 14 were more likely to be overweight. In addition, adolescents who were normal weight and had conduct problems at 14 had a higher likelihood of being overweight by ages 16 or 19.
Polygenic risk scores (PRS) were calculated to predict the risk of developing a condition based on associated genetic variations. The PRS for BMI — which explained 5.15% of the variance in BMI at age 14 — was associated with dieting and purging at 14 and 16 years. In turn, the score for ADHD was associated with purging at 16 and 19. Also, the PRS for neuroticism was linked to binge eating at 14 and 16 years.
These results indicate that genetic risk factors for obesity, ADHD, and neuroticism are correlated with DEBs.
Dieting at age 14 was associated with future depression, generalized anxiety, self-harm, emotional problems, and smoking. Likewise, purging at 14 was associated with depression and anxiety symptoms later in adolescence.
“To our knowledge, this is the first study combining a large array of assessments, including genetics, personality, behavior, and mental health symptoms … to identify factors that were associated with the development of DEBs before their onset,” the researchers wrote.
“These results may have clinical implications for targeted ED prevention programs,” they wrote, adding that genetic and physical trait assessments of BMI, impulse control problems, and personality “may inform early and differential diagnoses of eating disorders.”
Among the study’s limitations, the investigators said, was the small number of male participants, which prevented an analysis of sex differences in DEB development. A lack of inclusion of other demographic factors that might affect analysis and potential inconsistencies in used measures also were cited as study limitations.