Eating Disorders

Overview of Eating Disorders

Eating disorders are serious psychiatric disorders characterized by abnormal eating or weight-control behaviors. Disturbing attitudes towards weight, body shape, and eating play a key role in their origin and maintenance. The form of these concerns varies by gender; in men, for example, body image concerns might focus on muscularity, whereas in women, these concerns might focus more on weight loss. Obesity per se is not framed as an eating disorder. All eating disorders considerably impair physical health and disrupt psychosocial functioning. Both the diagnostic and statistical manual (DSM-5) and the international classification of diseases (ICD-11) encompass six main feeding and eating disorders. These include the familiar diagnostic categories of anorexia nervosa, bulimia nervosa, and binge eating disorder. In addition, three disorders previously mainly viewed as childhood disorders have been included. These are avoidant-restrictive food intake disorder, pica, and rumination disorder. DSM-5 also provides subtype qualifiers, severity indicators, and definitions of remission.

Aetiology of Eating Disorders

Aetiology diagram of restrictive-type eating disorders

Biological factors Genetic predisposition Gender: female-male ratio=10:1 Obsessive-compulsive or autistic spectrum traits Behavioral susceptibility to appetite dysregulation Metabolic vulnerability Environmental influences in the perinatal period
Psychological factors Personality traits (rigidity, attention to detail, intolerance of uncertainty and mistakes, perfectionism) Cognitive rigidity with high cognitive control over drives High ability to delay reward Decreased facial expressivity and ability to decode non-verbal signals from others Reduced theory of mind Increased sensitivity to social ranking and threat Reduced ability to interpret and reciprocate in social interaction Body image disturbance Alexithymia
Psychosocial factors Parental eating problems Peer stress (eg., bullying) Trauma (exposure) Culture (industrialized/western) Thin idealization Middle-to-high socioeconomic status (high education of parents)	Behavioral factors Overcontrol of weight and eating Weight control behaviors Overconcern with body-mass index Coping by avoidance or perfectionism Social isolation Impaired physical and mental quality of life

Aetiology diagram of bulimic spectrum eating disorders

Biological factors Genetic predisposition (uncertain) Gender: female-male ratio=3:1 Metabolic vulnerability Ethnicity: increased prevalence in Asians Behavioral susceptibility to appetite dysregulation
Psychological factors Childhood adversity Attention-deficit hyperactivity disorder traits (impulsivity and difficulty paying attention) Inability to delay reward Social cognition problems with emotional avoidance Body image disturbance Alexithymia
Psychosocial factors Parental eating problems Peer pressure (e.g., bullying) Fat talk (i.e., conversations including negative and disparaging comments about body shape or eating behaviour) from peers, family, authority figures Trauma (exposure) Culture (industrialized/western) Thin idealization	Behavioral factors Weight control behaviours Overconcern with body-mass index Coping by avoidance or perfectionism Social isolation Impaired physical and mental quality of life

Treatment of Eating Disorders

Early intervention improves outcomes; therefore, rapid commencement of specialized eating disorder treatment and care rather than watchful waiting is essential. For mild or moderately severe cases, the first step is an outpatient psychological treatment involving family members in an age-appropriate manner. If the medical or psychological risk is high or there is an irresponsiveness to outpatient care, then the greater intensity of care can be provided by outreach, day, or inpatient facilities. Studies in the UK National Health Service suggest that about 20-35% of patients will need this higher level of care. There is uncertainty about the management of patients who continue to be symptomatic following these first-line treatments, although recovery remains possible for more than 60% of patients even after 20 years. Patients often request that their families and treatment teams should not give up on them. New forms of treatments are being considered for this group, but some aspects of management are controversial. Transitions between services for age, educational, or physical reasons need to be carefully managed.

Trend of Research

Over the past 50 years and in the context of major changes in our environment, eating disorders have evolved into a variety of forms with overlapping and distinct clinical and aetiological features, affecting people of all ages and social classes. The prevalence of eating disorders is moderately high, although most affected individuals do not present for treatment. Lengthy periods of untreated symptoms can lead to an entrenched form of illness, which is more difficult to treat. In brief, advances are needed to allow more precise elucidation of the mechanisms that underpin these problems and to develop more targeted treatments. At the same time, disseminable and scalable treatments are needed.