Star Study: Psychological research into eating disorders ...



Star Study: Psychological research into eating disorders: Wonderlich et al (1996)

Read the introduction first and answer the following questions:

1. What is the prevalence of Bulimia nervosa according to this article?

2% of adolescent and young adult females.

2. What are the symotoms of bulimia?

recurrent binge eating, a lack of control over eating during such episodes, the purging of food to regulate body weight, and excessive concern about body shape and weight

3. Name 5 frequently identified risk factors

sociocultural pressure for women to be thin, histories of dieting, low self-esteem, body dissatisfaction, mood instability.

4. What do the authors think may also be an important risk factor?

childhood sexual abuse

5. What does existing research evidence suggest about this idea?

Contradictory evidence about the relationship between childhood sexual abuse and bulimia nervosa some studies support the relationship while others fail to find such an association. Supporting literature criticized due to problems with the control groups; Pope and Hudson meta analyses; evidence against:

6. What do the authors think of this conclusion?

Premature: some of the studies that found no relationship looked at mixed sample of both anorexic and bulimic individuals and thus did not adequately evaluate whether childhood

sexual abuse was related specifically to bulimia nervosa.

Another study9 that did not find an increased rate of eating disturbance in sexual abuse victims included subjects who were abused as adults; moreover, 68% of the victims were abused on only one occasion, which is not representative of the typical childhood sexual abuse experience, especially that involving intrafamilial abuse.

Furthermore, all but one of the studies reviewed by Pope and Hudson relied on clinical samples of women who were seeking treatment for eating disorders, which may limit the generalisability of the findings.

Finally, the available studies are unable to show how necessary sexual abuse is as a risk factor for bulimia.

7. How do the authors propose to overcome the methodological problems of previous studies?

Using detailed, structured questions to assess the history of childhood sexual abuse and selected bulimic behaviours in a representative sample of US women in the general population.

8. What was the general hypothesis and what further predictions are made? What are the reasons behind these predictions?

Childhood sexual abuse is a risk factor for bulimic behaviour.

(1) Sexually abused women will be more likely to report binge eating behaviour.

Clinical theories suggest that psychological traumas such as sexual abuse result in long-term psychobiological deficits in affect regulation that may in turn increase the risk of binge eating as a coping strategy.

(2) Sexually abused women will be more likely to express excessive concern about body shape and weight.

Clinical studies suggest that victims of childhood abuse often express low self-esteem and body dissatisfaction.

(3) Sexually abused women will be more likely to combine both binge eating and purging behaviours (such as vomiting, laxative abuse, and extreme forms of dieting or exercise).

If sexual abuse victims are prone to both binge eating and concerns about body shape and weight (as predicted), they should also be more likely to rid themselves of calories through purging to prevent weight gain.

(4) Sexually abused women will be more likely to display all three bulimic behaviours under study (binge eating, purging, and excessive weight concern), a set of behaviors that approximate the diagnostic criteria for bulimia nervosa in the Diagnostic and Statistical Manual of Mental Disorders, 3rd edition, revised (DSMIII-R).17

Aim:

Wonderlich et al (1996) aimed to discover the extent to which childhood sexual abuse is a necessary risk factor for bulimia nervosa.

Previous research was contradictory and many studies were flawed, e.g. used mixed samples of people with anorexia and bulimia, included Pps abused as adults and included Pps who been abused only once (not typical of the type of childhood sexual abuse by family members).

Wonderlich et al aimed to overcome these methodological problems and show that sexually abused women are be more likely to report binge eating and purging behaviours (such as vomiting, laxative abuse, and extreme forms of dieting or exercise) and express excessive concern about body shape and weight.

Now read the method

1. What research method is used in this study?

longitudinal survey

2. Who were the sample? Number of Pps, age and culture

a representative sample of 1099 US women living in non institutional settings; aged 21+

3. How as the data collected?

Female interviewers conducted face-to-face interviews

4. How were the symptoms of bulimia nervosa operationalised?

questions for assessing bulimic behaviours were taken from the Structured Clinical Interview for DSM-HII-R (SCID) Respondents were asked if they (1) believed they were more concerned about body shape and weight than other people their age; (2) had ever eaten abnormally large amounts of food within a few hours at least twice a week for 3 months or more; and (3) had ever engaged in counteractive behaviors such as vomiting, laxative use, or severe dieting during such eating episodes.

5. How was childhood sexual abuse operationalised?

Childhood sexual abuse was measured by detailed questions about sexual experiences before the age of 18. Women were not asked if they had been sexually abused; instead, they were asked if they had ever experienced particular sexual acts, including exhibitionism, sexual kissing, touching and fondling of genitals, oral-genital activity, and vaginal and anal intercourse. Based on research by Wyatt, childhood sexual abuse was defined as (1) any intrafamilial sexual activity before age 18 that was unwanted by the respondent or that involved a family member 5 or more years older than the respondent; and (2) any extra familial sexual activity that occurred before age 18 and was unwanted, or that occurred before age 13 and involved another person 5 or more years older than the respondent. Voluntary experiences between ages 13 and 17 with partners 5 or more years older were not included in the definition of abuse.

Results section

1. What percentage were classified as having been sexually abused in childhood?

24% and this was considered reliable and representative.

2. What was the relationship between binge eating, by itself or in combination with counteractive behaviors and childhood sexual abuse?

Binging and purging were two or more times more prevalent among the women who had experienced childhood sexual abuse than among the women who had not.

3. What was the relationship between heightened concerns about weight and body shape and childhood sexual abuse?

although much more prevalent than bingeing and purging, this was not related as strongly to childhood sexual abuse.

4. According to the statistical technique, ‘attributable risk analysis’, what percentage of cases of bulimia nervosa would not have occurred if women had not been sexually abused as children?

as many as 17% of women reporting binge eating experiences, and 30% of women reporting a history of binge eating combined with counteractive measures, would not have had these bulimic experiences in the absence of childhood sexual abuse.

5. For what proportion of the sample was childhood sexual abuse apparently an essential precondition?

between one sixth and one third of the more serious cases

Findings

Following a longitudinal survey, Wonderlich et al found …………….% of their sample had been sexually abused in childhood and that binging and purging were ………………….. times more common in the abused group than the non-abused group.

However, such abuse was much ……………. relevant to women's odds of being highly concerned about their …………….. and ……………….

Using a technique called ‘……………………………….. analysis’, they also found that of the ………………… only group, …………….% would not have had these behaviours had they not been abused and that ……………% of the binge-purge group would have been free of these behaviours had they not been abused.

In summary, Wonderlich et al found that that in between one ……………….. and one ……………. of the more …………………… cases of bulimia behaviour childhood sexual abuse was apparently an essential ……………………………..

Conclusions

1. What two conclusions do the authors suggest can be drawn from their study?

1) experiences of childhood sexual abuse by themselves are unlikely to be sufficient to cause bulimic behavior, but

2)A large fraction of women who engage in binge eating and purging would not do so if they had not been sexually abused as children.

2. What possible reason for these findings are suggested?

psychological traumas such as sexual abuse result in long-term psychobiological deficits in affect regulation that may in turn increase the risk of binge eating as a coping strategy. Clinical studies suggest that victims of childhood abuse often express low self-esteem and body dissatisfaction. If sexual abuse victims are prone to both binge eating and concerns about body shape and weight (as predicted), they should also be more likely to rid themselves of calories through purging to prevent weight gain.

3. The study provides support that which aspects are more likely to be linked to childhood sexual abuse –

• behavioural aspects of bulimia (binging and purging)

or

• cognitive aspects (excessive concern about body weight an shape)

Conclusions

Following a study exploring the relationship between childhood sexual abuse and the prevalence of bulimic tendencies in later life, Wonderlich et al (1996) conclude that experiences of childhood sexual abuse alone are ………………………. to be ……………………… to cause bulimic behavior, however a large ………………………. of women who engage in binge eating and purging would not do so if they had not been sexually abused as children.

They suggest that the binge/purge cycle may have been …………………………. as it reduced negative affect associated with previous sexual abuse. This is an example of ………………………… reinforcement and supports the …………………………….. model of abnormality.

It can be concluded that psychological trauma in childhood may be associated more with the ……………………………….. aspects of bulimia than the …………………………… aspects since there was not a strong relationships between excessive concern about body shape and weight and childhood sexual abuse.

Criticisms

1. What yellow hat strengths does this study have, which add validity to the findings?

representative national sample of women in the general population, multivariate analyses, and rigorous criteria for identifying childhood sexual abuse.

2. What evidence is there that the findings are reliable?

Two other surveys that relied on representative national samples of women (in the United States and Canada) have also recently revealed a similar association between childhood sexual abuse and bulimia nervosa.

3. Why do the authors think that there may be many causes for bulimic behaviours that are unrelated to childhood sexual abuse?

There was a high prevalence of weight concerns among all the women interviewed (more than 30%) which suggests that weight preoccupation may be so common among US women today that it has many causes unrelated to childhood sexual abuse.

4. These findings suggests that binging and purging have been found to be helpful in dealing with negative emotions associated with the abuse and are therefore a way of coping.

Which principle from operant conditioning explains why these behaviours have become more common in these women.

• Positive reinforcement

• Negative reinforcement

• Positive punishment

• Negative punishment

5. Which model(s) of abnormality does this study support?

Behavioural model

6. What other factors do the authors suggests should be considered when trying to work out which victims of childhood sexual abuse will actually go on to suffer from bulimia?

body image concerns, extreme dieting, mood disturbances, social relationship problems

7. What methodological flaw means that it is not possible to say that childhood sexual abuse preceded bulimic behaviour and may therefore have been a causal factor?

The survey also did not verify that the onset of bulimic behavior occurred later than childhood sexual abuse.

8. What is the term which describes the situation whereby interviewers may be more likely to unveil childhood sexual abuse in interviewees if they know or suspect that the interviewee has bulimic behaviour? How could this problem be overcome?

Interviewer bias, single blind condition, not face to face so can’t see body weight or shape. Questionnaire not interview.

9. Why is it unlikely that interviewer bias played a part in this study?

Questions were asked about so many different things.

10. What other reason does the article suggests that may mean that people with bulimia may be more likely to report sexual abuse? Why do the authors think that this was not a problem in this study?

Effort after meaning; they are motivated try and understand why they become bulimic particularly if they are receiving therapy; unlikely tin this study; majority responded that their memories of abuse were ‘not vague’.

11. The authors finally suggest that other family factors may make both bulimia nervosa and childhood sexual abuse more likely within a family thus making it appear that the two are related when in actually act both may be caused by problems within the family. What factors are cited?

Depression, substance abuse, psychiatric disorders

Develop two criticisms of the study by Wonderlich et al (1996); don’t forget criticisms can be positive as well as negative. Make sure you build enough detail each criticism.

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