8 Beh interventions and Eating dis Flashcards
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Abstract
• Food cue reactivity is a strong motivation to eat, even in the absence of hunger. T
• Therefore, food cue reactivity might sabotage healthy eating, induce weight gain and impede weight loss or weight maintenance.
• Food cue reactivity can be learned via Pavlovian appetitive conditioning:
- It is easily acquired but the extinction of appetitive responding seems to be more challenging.
• Several properties of extinction make it fragile:
- extinction does not erase the original learning and extinction is context-dependent.
- . These properties threaten full extinction and increase the risk of full relapse
• Extinction procedures are discussed to reduce or prevent the occurrence of rapid reacquisition, spontaneous recovery, renewal and reinstatement after extinction
• A translation to food cue exposure treatment is made and suggestions are provided, such as conducting the exposure in relevant contexts, using occasional reinforcement and targeting expectancy violation instead of habituation
• A new hypothesis proposed here is that the adding of inhibition training to strengthen inhibition skills that reduce instrumental responding, might be beneficial to improve food cue exposure effects
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Intro
• Appetitive responses to cues that signal the availability of food are collectively called food cue reactivity; the responding prepares the body for food intake and increases one’s motivation to eat
• Food cue reactivity during exposure to tasty foods is a normal and healthy response
• However, compared to people without eating concerns, food cue reactivity is significantly stronger in concerned eaters, such as unsuccessful dieters, bulimia nervosa patients, binge eaters and obese people
• Increased food cue reactivity motivates eating, even in the absence of hunger and in excess of calories physically needed, and therefore easily results in overeating and weight gain
- the amount eaten correlated strongly with increased salivary responding during exposure to the food
• Food cue reactivity not only contributes to the maintenance of overeating and weight gain – it also increases the risk of relapse during and after weight loss
• Though there exist individual differences in food cue reactivity [14,50], increased reactivity to food cues usually follows from Pavlovian appetitive conditioning, i.e., associative learning
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Acquisition of food cue reactivity Pt.1
• Food cue reactivity is easily learned.
• The early observations of Ivan Petrovich Pavlov are the most well-known: Pavlov observed digestive preparatory responses (e.g., salivation) in response to stimuli that signaled dog food, for example specific sounds or footsteps of the person feeding the dog
- During Pavlovian conditioning - or associative learning - the organism learns that a neutral stimulus predicts the occurrence of a second stimulus (e.g., the eating of dog food). The neutral stimulus will soon produce the same response in the organism as the second stimulus – in the above mentioned case of Pavlov’s dog: salivation.
- A large number of animal studies show that physiological responses elicited by food intake (e.g. insulin release, blood sugar increase and salivation) can be brought under the control of any stimulus predictive of food intake, such as odors, sounds, lights and time of the day
- Context cues are also able to drive consumption: Rats consume significantly more lesspreferred food (chow) when exposed to context cues that were previously paired with the intake of highly palatable foods
- Cue-conditioned overeating is quickly learned and particularly strong when palatable foods (high in calories, fat, salt and sugar) are involved in the cue - intake associations
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Acquisition of food cue reactivity Pt.2
- Similarly, it is relatively easy for humans to learn food cue reactivity and cued eating through associative learning
- Environmental contexts can also act as signals for intake.
- Potentially every stimulus or context can act as a food-predicting signal: food preparing rituals, the seeing, smelling and tasting of foods, interoceptive contexts like physical state (hunger/deprivation, satiety), hormonal state, mood state, expectations, thoughts about foods, physical contexts like a room, specific location, shopping mall, furniture, television, music, computer, and so on
- When cues or contexts reliably predict intake, they are able to elicit mental representations76 of the US (food).
- When confronted with the cue or context (CS), memories of the tasty foods are activated and desires to eat, or food cravings, are triggered - even in the absence of hunger
- To summarize, in our current society, highly rewarding calories are easy-to-get: fast food is available everywhere and most people like it.
- Palatable high-calorie foods are primary positive reinforcers and have high potential for conditioning
- Any time food is ingested, the cues and contexts that are present at the time can become associated with eating
- Associative learning will be stronger when the probability relationship between exposure to cues/contexts and reinforcement increases and when the US is more intense (e.g., more calories, higher palatability)
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Extinction of food cue reactivity Pt.1
• Cued cravings might easily sabotage healthy eating.
• Dieting, losing weight and the maintenance of lost weight will also be more difficult with increasing levels of food cue reactivity
• A reduction in reactivity to tempting food cues could eliminate the primary motivation for eating and might facilitate healthy eating, adherence to restrictive diets, weight loss and weight loss maintenance
- . Indeed, obese individuals who have successfully lost weight salivated significantly less during food cue exposure compared to unsuccessful obese dieter
• Pavlovian learning theory posits that Pavlovian extinction is the royal road to learn that a cue or context predicts no longer predicts intake.
• During a most straightforward Pavlovian extinction procedure, the cue or context that once signaled intake remains systematically unreinforced, i.e., the associated tasty foods are no longer eaten
- Consequently, cue reactivity or learned appetitive responding should diminish
• When a person is on a restrictive diet during which he is exposed to all kinds of food cues but he does not eat (i.e. he is not reinforcing the cues that signal eating), his cue reactivity should, in the end, extinguish. However, this may take a while and as long as the person remains cue reactive his dieting efforts are easily undermined
• In addition to natural extinction by restrictive dieting being a lengthy process, many dieters do not expose themselves to powerful foodsignaling cues as long as they are on a diet
• . For successful dieting and a reduction of overeating, decreased cue reactivity seems necessary
- But even when cue reactivity successfully extinguishes, food cue reactivity can easily return
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Extinction of food cue reactivity Pt.2
Bouton
• Bouton [11–13,26] discusses several properties of extinction that make it fragile:
- Extinction does not erase the original learning and extinction is context-dependent
1. Extinction is not unlearning. - Extinction is not simply the forgetting or unlearning of an existing cue - intake association.
- Instead, extinction adds a new memory to the existing one: During extinction, the individual gradually learns that the cue (CS) might also predict no US, no eating.
2. Extinction is context-dependent. - Whereas the acquisition of CS - US associations readily generalizes, extinction is largely context dependent.
- Context is a broad concept: It includes exteroceptive background cues like the physical environment as well as interoceptive cues such as mood states, hormonal states, states of deprivation (hunger or satiety), drug states, time, passage of time and specific thoughts
- One implication of context-dependent extinction is that a return of cue reactive responding is possible when the context changes.
- extinction procedures that reduce or prevent the occurrence of rapid reacquisition, spontaneous recovery, renewal and reinstatement after extinction are necessary to prevent full relapse.
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Dieting and learning Pt.1
• Diets differ in many respects. For example, some diets are very strict and rigid, while others are more flexible. Some people just try to eat less of many food items during regular meals, others only drink shakes, and others skip meals, and so on. Although we do not know much about behavioral dieting strategies], people who lost weight successfully do report that they are continually strict dieters who show little variety in their diets
• In line with these findings, Van den Akker et al. [76,78] proposed that dieters who frequently alternate restriction and eating in response to food cues may develop a learning schedule (partial reinforcement) that results in a slowed extinction of food cue reactivity (partial reinforcement extinction effect) and a greater difficulty to diet successfully.
• However, learning principles also predict that some flexibility in dieting can have beneficial effects by tackling rapid reacquisition of appetitive responding.
• The occasional reinforcement of a CS during acquisition and extinction was found to result in less rapid responding during reacquisition in humans, meaning that reacquisition (or relapse in clinical terms) was slower
- Occasionally cued eating during acquisition [76,78] or extinction [77] slowed down the extinction of expectancies and desires and also reduced the speed of the reacquisition of expectancies, but not eating desires.
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Dieting and Learning Pt.2
trials enable reinforced trials (cued intake) to be associated with extinction trials which could lead to more generalization between extinction and reacquisition contexts, thereby slowing reacquisition
- Thus, during occasional reinforced extinction, one learns that a reinforced cue might mean that the next trials will not be reinforced.
- In other words, eating in response to a cue does not automatically mean that additional reinforcements follow.
- The learning of occasionally reinforced trials might protect against this diet-breaking “what-the-hell effect”; the occasional reinforcement findings imply that dieters would benefit from occasional lapses in their diet because they learn that one reinforced cue (“lapse”) does not mean that all cues will be reinforced or even that a reinforced cue means that following cues are not reinforced
- Occasional reinforcement (lapses) will only be helpful when followed by new restriction; in occasionally reinforced extinction trials, one learns that lapses are infrequent and do not mean a full relapse
• The counterintuitive conclusion is that during dieting (extinction), occasionally eating ‘forbidden’ foods (US) in response to a food-signaling cue (CS) is actually helpful for achieving full abstinence.
• An interesting question here is how large the US should be in occasional reinforcement.
• These dieters should thus learn to associate the eating of a small appetizer with no further eating (unreinforced trial), and sometimes they should associate the eating of an appetizer with more eating (reinforced trial).
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Inhibition training
• Extinction is inhibitory learning and not unlearning, suggesting that extinction might be related to one’s ability to inhibit responding.
• Extinction procedures might therefore be more effective with stronger inhibition skills
• One study in our lab indeed demonstrated that participants with weak inhibition skills show worse extinction of appetitive responses compared to participants with stronger inhibition skills
• This is especially worth mentioning because a robust finding is that obesity and overeating are associated with weak inhibition skills
• It has been suggested that overeating follows in particular from a lack of inhibitory control over the hedonic, appetitive system
• In other words, people with weak inhibition skills usually show low eating restraint might need extinction procedures to extinguish their heightened food cue reactivity and appetitive responding, but they profit less from extinction procedures because they have weak inhibition skills.
• It is a new and interesting idea to test whether a simultaneous strengthening of inhibition skills would enhance extinction effects during food cue exposure.
- A series of studies into the effects of a computerized training to inhibit responses to food stimuli, using the Go-NoGo task, systematically shows reduced desires to eat and decreased snack intake
- During the Go-NoGo inhibition training, participants learn to respond to neutral stimuli or healthy foods (Go) while inhibiting responses to unhealthy foods (NoGo).
- The computer training consists of hundreds of trials in which the participant has to respond as quickly as possible (to healthy foods or neutral stimuli) - or to inhibit responding (to high calorie foods). Such training is effective in weakening operant responding.
• Another fascinating way to weaken operant responding could be the use of imagery.
- Just imagining consuming specific foods (M & M’s, cheese) by performing repetitive actions to bring the imagined food to one’s mouth (no actual food, no actual eating) decreased desires to eat and actual consumption
- The study shows that repeatedly simulating the act of eating without actual eating (i.e., without reinforcement) leads to decreased desires and decreased intake.
- In other words, repeated nonreinforcement of an eating response might lead to a suppression of actual eating behavior.
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Translation to the clinic: exposure therapy
• The clinical analogue of extinction is exposure with response prevention, a well-known behavioral intervention during which participants are repeatedly exposed to unreinforced cues.
• The food cue exposure with response prevention aims to extinguish food cue reactivity and decrease cued overeating.
• A recent neuroimaging study showed that prolonged food cue exposure (smelling chocolate) without eating leads to reduced reward-related activity in the chocolate lover’s brain
• It is argued that the violation of CS - US expectancies during exposure is more important for its effectiveness than the habituation of anxiety instead of habituation
• In line with the findings on anxiety from Craske’s lab, Schyns et al. [70]) showed that within-session habituation of cue reactivity (craving and salivation) did not correlate with food intake after prolonged exposure, whereas a significant correlation was found between the violation of expectancies and intake:
- Participants who successfully reduced their belief in “If CS then US” expectancies such as ‘If I have tasty foods in front of me, then I cannot resist eating them’ ate significantly less of the foods they were exposed to than participants whose beliefs were not reduced.
• Based on the new insights into extinction discussed in this paper, we propose some techniques that might improve current exposure for overeaters in clinical practice:
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Exposure therapy
Clinical Practice
- Do exposure in the overeating context
- When exposure is done in treatment settings, it is predicted that when a patient returns to the original (over)eating context, renewal will take place.
- For clinical practice, this means that extinction should be done in the contexts that best predict overeating.
- They can also include specific furniture, watching television, using the computer and several interoceptive contexts like physical states (hunger/deprivation, satiety), hormonal states, mood states, expectations, thoughts about foods, and so on.
- Cues used in isolation but also diverse combinations - Repeat exposure frequently
- The learning of new inhibitory pathways (CS means no US) is fragile at the start of exposure therapy.
- After exposure therapy, the CS is ambiguous and signals two possible USs: (over)eating or no (over)eating.
- The original association still exists and, if activated, the appetitive responding returns and a lapse or relapse might occur.
- One way to strengthen the new CS - no US memory, and to make it stronger than original CS - US memory, is to do frequent exposures and to include exposure homework in treatment.
- Frequent exposures might also reduce the risk of spontaneous recovery. - Eat ‘favorite foods’ under conditions that do not cue overeating- Demi lovato
- One risk for relapse is reinstatement that may occur when confronted with the US after extinction, e.g., when one eats favorite foods after extinction when cues or contexts are not present.
- During the exposure intervention, the individual should practice eating some ‘favorite foods’ (US) when the CS is not present (unpaired), for example eating them in contexts that would not quickly be associated with overeating. for example at work amongst colleagues, or with the therapist in a cafe.
- This is alternative overeating
- A normal overeating episode reinforces the link between cues and overeating, while the alternative overeating will not.
- Once an alternative overeating episode has been used, a new one is designed (e.g., eating some nuts in the garage).
- The alternative overeating episode is discussed in detail in advance and put in writing (flash cards) to make it easier to use. In this way, reinstatement can be prevented. - Eat ‘favorite foods’ under conditions that do cue overeating
- Another risk for relapse is the quick return of responding to the CS when a CS - US pairing is repeated after extinction (= rapid reacquisition).
- For example, if, after successful extinction, one overeats (US) again when confronted with a cue or context (CS) that used to predict overeating, a full-blown relapse is possible.
- Occasionally reinforcing the CS during extinction slows reacquisition (relapse)
- During exposure, the individual can practice eating some of the ‘favorite foods’ (US) when confronted with the CS.
- Disconfirmation of the belief that the “CS means US” (a full blown overeating episode or ‘always’ overeating) at the same time could be helpful to prevent relapse - Violate “If CS, then US” beliefs
- Habituation appears to be less important for the success of exposure than disconfirmation of “If CS, then US” beliefs.
- Strong, frequent and repeated violation of those beliefs does strengthen the learning of CS - no US associations
- For example, beliefs like “If I am alone at home with a box of chocolate, I will eat it all” or “If I eat one bite, I will eat it all” will be violated if the individual does not eat the entire box, or if only one bite is taken.
- The violation of these beliefs, which do maintain the undesired eating, seems to be important for effective exposure.
- Violation can be done by asking how big the chance is that the “If CS, then US” belief will happen during the exposure, and how long it will take to occur.
- For instance, when one predicts that eating the entire box of chocolate will occur within 10 min, the belief will be disconfirmed after 10 min of exposure.
- Thus, the end of an exposure session is guided by the time needed for disconfirmation of the belief, not by the time needed for habituation. - Add inhibition training
- A simultaneous strengthening of inhibition skills and inhibitory learning may enhance extinction effects during food cue exposure.
- This could be done by adding Go-NoGo training, the administration of D-cycloserine, transcranial electrical brain stimulation or the use of imagery
- It should be noted that it has not yet been studied whether adding these inhibition techniques indeed improves exposure effects
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Conclusion
• To conclude, food cue reactivity motives overeating and weight gain and impedes weight loss (maintenance).
• Food cue reactivity is easily learned but the extinction of appetitive responding is challenging.
• Food cue exposure treatment might benefit from new insights from the anxiety disorders field that can be translated into procedures to improve the extinction of learned food cue reactivity,
- like doing the exposure in relevant contexts,
- the using of occasional reinforcement,
- and expectancy violation.
• We propose that adding inhibition training can improve exposure effects by strengthening inhibition skills and thereby reducing instrumental responding.
Lec
Goals of CBT for eating disorders
• Helping the patient decide to change
• Normalizing the eating pattern
- Quit dieting, binging, purging, excessive exercise
- Eating regularly, eating enough, vary in products
• Tackle the core psychopathology of over-evaluation eating, shape, weight and their control
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Helping patients decide to change
• Try to help patients:
- Become interested in making a fresh start
- Becoming intrigued about discovering their true personality
- Be hopeful about the future
- Be keen to escape the effects of being underweight
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Body checking
• Problem: magnifying perceived imperfections and feeling out of control
• Weight checking is already addressed
• Patients need to become aware
• Help patients stop non-normative forms of shape checking
• Help patients modify/reduce normative forms of shape checking
• Think first:
- What am I trying to find out?
- Can I find it out this way?
- Will doing this make me feel better about myself?
- Does it make sense to do it so often?
• Educate about mirror use
