Partial Eating Disorder Syndromes Among Teens

Some 20 years ago, results of community surveys identified a profile of eating disorders that differed from those reported in treatment settings. In the community samples, fully fledged anorexia nervosa (AN) and bulimia nervosa (BN) appeared to be relatively rare, from about 0.5% for AN and 1.0% for BN. However, rates for partial syndromes, where some, but not all, of the criteria for diagnosis were present, ranged from 3% to 5%.

George C. Patton, MD, and colleagues at the University of Melbourne, Victoria, Australia, recently reported the results of their prospective study of the outcome of adolescent partial eating disorder syndromes in nearly 2000 participants (Br J Psychiatry 2008; 192:294). Between August 1992 and March 2003 Dr. Patton and his coworkers conducted an eight-wave cohort study of adolescent and young-adult health in the state of Victoria, Australia.

The group studied outcomes that included persisting eating disorders, symptoms of depression and anxiety, body mass, sexual and reproductive health, and social role transitions. One class from each school entered the cohort in the latter part of the 9th grade (wave 1). A second class entered the study 6 months later, early in the 10th grade (wave 2). The participants were then re-interviewed at four six-month intervals during their teen years (waves 3 to 6), with two follow-up waves when they were 20 to 21 years of age and 24 to 25 years of age.

Measurements

Height and weight were measured at baseline and at waves 7 and 8, using self-report forms. The Branched Eating Disorders Test (BET) was used to assess Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) criteria for eating disorders. The BET is designed to be used in teenagers in community samples, and covers symptoms of eating disorders over the past 4 weeks. Partial eating disorder syndromes were based on the DSM-IV criteria for BN and AN. A partial syndrome of AN was defined as meeting two of the following criteria: (a) low body weight, defined on the basis of a body mass index (BMI) z-score below the 5th percentile for age and gender; (b) an intense fear of gaining weight or becoming fat when under the 25th percentile BMI Z-score for age and gender; (c) disturbed experience of body weight, or size and shape when under the 25th percentile BMI Z-score for age and gender; or (d) amenorrhea, defined as missing three consecutive menstrual periods.

Defining a partial syndrome of BN

A partial syndrome of BN was defined as meeting at least two of the following criteria: (a) objective binge eating at least weekly for at least 4 weeks; (b) use of any of the following for at least 4 weeks: self-induced vomiting, laxative use, or use of diuretics at least twice weekly, daily fasting (12 hours or longer) for at least 4 weeks, or daily vigorous exercise to control weight; or (c) reporting that weight and shape were extremely important to sense of self.

Symptoms of depression and anxiety were studied from waves 1 to 7 using the Revised Clinical Interview Schedule (CIS-R). Specific anxiety and depressive syndromes were also defined with the CIS-R. The 12-item General Health Questionnaire was used to assess these symptoms at wave 8, or at the final interview. A cutoff score of 2/3 was used to define individuals with high psychiatric morbidity. Alcohol misuse and dependence were assessed with the Composite International Diagnostic Interview 2.1, 12-month version, to define DSM-IV categories. Cannabis use was assessed on the basis of self-reports of use over the past year; high use was defined as smoking cannabis at least once a week. Amphetamine use was defined as self-reported use in the past 12 months.

What the researchers found

Between the ages of 15 and 17 years (waves 3 to 6), nearly 1 in 10 of the female participants had some of the criteria for an eating disorder. One participant fulfilled all criteria for AN, and 4 fulfilled all criteria for BN. Eight participants fulfilled criteria for partial syndromes of AN and BN at different points in time. The prevalence rate for partial syndromes in male participants was low, just over 1%. The risk of developing an eating disorder was from 4 to 15 times greater for female participants than for male participants.

Health outcomes for the participants

When the group reviewed health outcomes of the participants at age 20 or age 24, partial eating disorders were identified in 14% of those who had a bulimic partial syndrome, and 21% of those who had an anorexic partial syndrome during adolescence. New partial syndromes were uncommon in young women without a diagnosis during their teens. Forty-four percent of those with a partial syndrome during adolescence reported significant psychiatric morbidity by the time they were 20, compared with 20% of other cohort participants. The same pattern was evident at the age of 24: 40% of those with an adolescent partial syndrome reported high levels of morbidity on the General Health Questionnaire, compared with 25% of those who had no partial syndromes as adolescents.

The results of the study confirmed that partial eating disorder syndromes are common during adolescence. About one in 6 adolescents with a partial eating disorder in their teens had a persisting partial syndrome as a young adult. There was little evidence to suggest that partial syndromes progress to clinical eating disorders between adolescence and young adulthood; nevertheless, female participants with a partial syndrome during their teens had a wide range of ongoing health and social problems as young adults.

Early intervention is important

According to the authors, their findings indicate the value of early intervention for teens who have depression and anxiety, substance misuse and sexual health problemsall common in those with partial syndromes. Self-help interventions in community settings, tied to promotion of better knowledge about eating disorders, might be one way to reduce the high physical and psychological costs of eating disorders during adolescence.