January 10th, 2018
Diagnostic criteria for Anorexia Nervosa
AN is mainly characterized using criteria advanced in two instruments – the Diagnostic and Statistical Manual for Mental Disorders – IV (DSM-IV) and the International Classification of Diseases – version 10 (ICD-10) (Bulik et al., 2005). Although differing in detail, both instruments consider weight, behavioral manifestations, body perception and hormonal fluctuations in characterizing AN. With respect to weight, AN is indicated by a weight level below 85% of an individual’s expected ideal weight (Bulik, et al., 2005, p. s3). Alternatively, AN may present itself in an individual’s failure to attain the expected weight gain during the growth period, especially during the prepubertal stages (Bulik, et al., 2005, p. s3). ICD-10 has an additional weight-based metric for AN i.e. a Quetelet’s body mass index lower than 17.5 kg/m2 (Bulik, et al., 2005, p. s3). Accordingly, a clinician could make a diagnosis of AN by inquiring about the past weight and weight-loss patterns of the individual s/he suspects to be suffering from AN.
DSM-IV and ICD-10 also use behavioral manifestations to characterize AN. The instruments for instance advance that individuals with AN intensely fear gaining weight thus become overly preoccupied with avoiding foods they perceive to be fattening (Bulik, et al., 2005, p. s3). The individuals could also engage in habits such as self-induced vomiting, excessive exercise, self-induced purging, binge eating and use of appetite suppressants (Bulik, et al., 2005, p. s3). Unlike ICD-10, DSM-IV distinguishes between restricting AN (where AN is not accompanied by binge eating or purging) and Binge-eating/purging AN – where such behaviors are a feature of the resultant AN (Bulik, et al., 2005, p. s3). To diagnose AN based on behavioral-informed criteria, a clinician can inquire about an individual’s eating habits; for instance, asking the individual what s/he ate the previous day and whether s/he engages in binge-eating.
Patients with AN also have a distorted perception of their body. In this respect, they place excessive importance on body weight or shape during self-evaluation, thus impose low weight thresholds on themselves (Bulik, et al., 2005, p. s3). Such a perception influences the way one experiences one’s weight and shape in a way that makes one dread the idea of gaining weight (Bulik, et al., 2005, p. s3). To make a diagnosis based on this criterion, a clinician can inquire whether an individual perceives oneself to be fat. Other manifestations of AN include hormonal fluctuations where amenorrhea (“the absence of at least three consecutive menstrual cycles”) occur in females and loss of sexual interest and potency in males (Bulik, et al., 2005, p. s3). Hormonal fluctuations may also include increases in levels of growth hormone and cortisol and impairment in peripheral metabolism of thyroid hormone as advanced in the ICD-10 criteria (Bulik, et al., 2005, p. s3). Use of amenorrhea as a criterion to diagnose AN may however be misleading when individuals suspected to have AN are on birth control pills to regulate their menstrual cycle (Bulik et al., 2005). ICD-10, additionally characterizes AN based on pubertal development, advancing that a delayed sequence of events (e.g. breast development in girls and genital development in boys) following prepubertal onset may indicate a case of AN (Bulik, et al., 2005, p. s3). Go to part 3 here.