INFORMATION PROCESSING BIASES IN MUSCLE DYSMORPHIA AND ANOREXIA NERVOSA

SCOTT GRIFFITHS

PROF STEPHEN TOUYZ

DR STUART MURRAY

PROF DAVID ALAIS

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Men are no longer “immune” to eating disorders

› Men no longer "immune" to eating and body image disorders

- 15-30% of anorexia and bulimia diagnoses (Hoek & Hueken, 2003; Hudson et al. 2007)

- 30-40% of binge eating disorders (Muise et al. 2003)

- 25% of early onset eating disorders (Madden et al. 2009)

- 100% increase in binge eating, purging and strict dieting from 1995 to 2005 (Hay et al. 2008)

- Young Australian males rate body image as their most significant concern (Mission Australia, 2007, 2010)

- Men with EDs feel that society believes EDs to be a "female issue" (Robinson et al. 2012)

- "Overlooked, understudied and underreported" (p464, Greenberg & Schoen, 2008).

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Men want to be lean and muscular, not “thin”

› The ideal Western male body (as desired by most men)

- V-shaped torso (Pope et al. 2000)

- Broad shoulders, narrow waist

- Well-developed, visible musculature

- Especially in the upper body (chest, arms, shoulders)

- Big biceps especially important (McCreary et al. 2006)

- 6-pack (Nikellen et al. 2012)

› Men pursue a muscular ideal, not a thin ideal (Bergeron & Tylka, 2007)

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What’s causing all this?

› The media is probably at fault.

- Action figures have gone from regular-guy to jacked (Baghurst et al. 2006; Pope et al. 1999)

- Male analogue for barbie dolls getting thinner and bustier.

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What’s causing all this?

› The media is probably at fault.

- Video game characters promulgate the hypermuscular male ideal (Barlett & Harris, 2008)

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What’s causing all this?

› On campus at the University of Sydney

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Not yet classified an eating disorder.

Muscle dysmorphia (Pope et al. 1997)

› Originally named "reverse anorexia" (Pope, Katz & Hudson, 1993)

› Criteria

- Preoccupation with being lean and muscular

- At least 2 of the following:

- Giving up important actities due to a compulsive need to work out and diet

- Avoiding body exposure/enduring body exposure with intense anxiety and distress

- The preoccupation with body size/musculature causes impairments in important activities

- Continuing to work out, diet or use steroids/PEDs despite knowledge of adverse physical or psychological outcomes

- Not better accounted for by anorexia nervosa or body dysmorphic disorder.

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The drive for thinness taken to the extreme

Anorexia nervosa

› Criteria

- A refusal to maintain body weight at or above a minimally normal weight for age and height (BMI <= 17.5)

- Intense fear of gaining weight or becoming fat, even though underweight

- Disturbance in the way in which one's body weight or shape is experienced, undue influence of body weight or shape on self-evaluation, or denial of the seriousness of the current low body weight.

- In post-puberty females, amennorrhea (no period for at least 3 conseuctive menstrual cycles

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› Set shifting difficulties (Danner et al. 2012; Darcy et al. 2012; Oldershaw et al. 2011; Roberts, Tchanturia & Treasure, 2012; Tchanturia et al. 2012)

- An inability to adapt to changins to situational demands

› Weak central coherence (Danner et al. 2012; Harrison et al. 2011; Lopez et al. 2009; Oldershaw et al. 2011; Southgate et al. 2008).

- A preferential bias for processing detail at the expense of global processing

› Thought to be traits, not states (Kanakam et al. 2012; Danner et al. 2012; Roberts, Tchanturia & Treasure, 2012; Tenconi et al. 2010).

› Incorporated into recent aetiological, maintenance and treatment models of eating disorders (Baldock & Tchanturia, 2007; Schmidt & Treasure, 2006; Southgate & Tchanturia, 2005).

Information processing biases in the eating disorders

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› Studies of information processing biases almost always performed on women, using measures that are oriented toward the thin-ideal.

› No study has investigated information processing biases in men with anorexia, or men with muscle dysmorphia.

› Furthermore, no study has investigated information processing biases as they relate to the predominant male experience of body dissatisfaction

- I.e., Insufficient muscularity and muscularity-oriented disordered eating.

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› Study 1

- "Information processing biases in muscle dysmorphia and anorexia nervosa"

› Clinical population

› Participants

- 25 men diagnosed with AN

- 25 men with MD

- 25 controls

Two studies on set shifting difficulties and weak central coherence

› Study 2

› "The drive for muscularity and muscularity-oriented disordered eating in men: The role of set shifting difficulties and weak central coherence

› Non-clinical population

› Participants

- 91 male undergraduates

- Fluent in English

- No current or previous diagnosis of depression, OCD,

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› Participants

- 91 male undergraduates

- All fluent in English

- Mean age of 20

- Mean BMI of 23

- Mean predicted IQ of 109

- No current or previous history of an eating disorder

- No current diagnosis of depression or obsessive-compulsive disorder

- No history of a serious head injury involving ongoing complications

Study 1: “Set shifting difficulties and weak central coherence predict drive for muscularity and disordered eating in men”

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› Participants connect the dots as fast as possible:

- Trail A (1-2-3-4-5-6 etc.)

- Trail B (1-A-2-B-3-C-4 etc.)

The Trail Making Task (Reitain, 1959)

Tests of set shifting

Wisconsin Card Sort Test (WCST; Heaton et al. 1993)

› Stimulus card is matched to 1 of the 4 category cards (according to a categorisation rule (colour, shape or number).

› Rule changes after 3 consecutive correct responses

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Rey-Osterrieth Complex Figure (ROFC; Osterrieth, 1944).

› Participants copy the figure and then recall it from memory without warning after a delay period.

› Figure contains both local and global elements.

› Coherence index (Booth, 2006)

Tests of central coherence

Matching Familiar Figures Test (MFFT; Kagan, 1964)

› "I will be recording both your speed and your accuracy" (word order is counterbalanced).

› Performance based on latency to first response and total number of errors.

› Calculate "efficiency index" (Southgate, Tchanturia & Treasure, 2008)

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Hierarchichal multiple regression analyses

Results from Study 1: Set shifting and central coherence in male undergraduates

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› Evident in the instruments used to measure disordered eating

- EDE-Q (Fairburn & Beglin, 1984)

- "Have you been deliberately trying to limit the amount of food that you eat?"

- "Have you wanted your stomach to be empty?"

- "Have you gone for long periods of time (8 hours or more) without eating anything in order to influence your shape or weight?"

- "Have you had a definite fear that you might gain weight or become fat?"

- "Have you definitely wanted your stomach to be flat?"

- "Have you had a strong desire to lose weight?"

- "Have you felt fat?"

- "Have you taken diuretics to control your shape or weight?"

- "Have you taken laxatives to control your shape or weight?"

The current conceptualisation of disordered eating is synonymous with body fat, fat loss, weight loss and calorie restriction.

Study limitation: The dilemma of disordered eating

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- Macronutrient targets, with heavy emphasis on high protein consumption.

- Consumption of meal replacement shakes and protein shakes to increase calorie/protein intake

- Interrupting important activities to accommodate frequent eating (often every 3 hours)

- Importance placed on the functionality of food as opposed to the taste.

- Cooking meals for days (or weeks) in advance.

- Refusal to eat food for which calorie information is unknown (e.g. at restaraunts)

- Forcing food down when not hungry,

- Liquifying/blending food for easier food intake

- Restrictive food choices ("the chicken, brown rice and brocolli diet") or total elimination of carbohydrates or fats (Higher in MD than in AN [Murray et al. 2012])

- Use of steroids, "testosterone boosters" and other supplements

Eating behaviours motivated by the desire to gain muscle are not captured by existing measures, but can be extremely disordered.

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› Researchers have reversed problematic items on the EDE-Q (Murray et al. 2012).

- E.g. "Have you gone for long periods of time (8 hours or more) without eating to influence your shape or weight?"

-> "Have you gone for short periods of time (3 hours or less) whilst eating to influence your shape or weight?"

› The ideal male body is high in muscularity + low in body fat.

- Constant balance between eating behaviours aimed at shed body fat and eating behaviours to gain muscle.

› What makes eating disordered is the rule underlying the behaviour, not the direction.

- "Do you eat meals based on time intervals, rather than based on feeling hungry?"

We need to revisit our conceptualisation of disordered eating

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› 3 hypothetical factors:

- Behaviours

- "I eat meals throughout the day based on time intervals rather than based on feeling hungry"

- Attitudes

- "The taste of the food is more important than the functionality" (reverse coded)

- Concerns/Anxiety

- "I would feel anxious eating food that I had not prepared myself"

The Muscularity-Oriented Eating Test (MOET)

Future research: Beyond information processing biases in muscle dysmorphia and anorexia nervosa