Reduced Specificity of Autobiographical Memory in Anorexia Nervosa
Kovács , Tímea, Szabó, Pál, Pászthy, Bea, Journal of Cognitive and Behavioral Psychotherapies
During the past years many researchers have focused their attention on autobiographical memory and its deficits in clinical samples suffering of emotional disturbance. The aim of this research was to study autobiographical memory functioning in anorexia nervosa patients, taking into account the duration of illness, the subjective evaluation and the date of the recalled memory, the pleasantness of the recalled memory and the level of depression. Patients with restrictive anorexia nervosa were compared with a group of healthy teenagers using the Autobiographical Memory Test, the Child Depression Inventory and the Eating Disorder Inventory. Anorexic girls recalled more general (extended and categoric) memories than the controls for each type of cue word (positive, negative and neutral), suggesting a general difficulty in the access to emotional memories.
Keywords: anorexia nervosa, autobiographical memory, specific memory, depression
In the past few decades a new line of research focusing on autobiographical memories has drawn increasing attention of scientists all over the world (Healey & Williams, 1999). Autobiographical memory refers to memories with personal content retrieved easily by the individual, that are not part of a generic script or semantic memory, but which form individual autobiography (Swales & Williams, 2001). The dominant paradigm for assessing autobiographical memory - the autobiographical memory test (AMT) - was developed by Williams and Broadbent (1986). They studied patients a few days after they had been hospitalized for a serious suicide attempt. These individuals were asked to retrieve specific autobiographical memories to positive or negative cue words (e.g., happy, angry). A specific memory is defined as 'something that happened at a particular place and time and took no longer than a day to occur'(for example, "Last Sunday when I went out for a coffee with Mary"). Responses were compared to normal controls. Despite the fact that they were asked to retrieve specific memories, the overdose patients tended, as a first response to the cues, to retrieve more inappropriately general memories than controls (For example: "When I am with Mary". These general memories can be further qualified as categoric general memories, referring to events that occur often, and extended general memories, referring to events that last more than one day, or no memories (semantic associations) and no response or same event.
Several studies found that depressed patients (Brewin, Reynolds & Tata, 1999; Hermans, Van den Broeck, Belis et al., 2004), patients with bipolar depression (Mansell & Lam, 2004) and patients suffering from PTSD (McNally, Lasko, Macklin et al., 1995) show lack of specificity compared to controls. A number of studies have demonstrated that general memory is associated with poor problem solving (Arie, Apter Orbach et al., 2008; Sutherland & Bryant, 2008; Williams, Barnhofer & Beck, 2005).
Eating disordered patients often experience depression (Santos, Richards & Bleckley, 2007; Speranza, Corcos & Loas, 2005) and they have problem solving deficits (Cooper, 1995). Memory functioning in eating disorders was analyzed in many studies (Carter, Bulik, McIntosh et al., 2000; Hunt & Cooper, 2001; Davidson & Wright, 2002), but studies related to autobiographical memory functioning in eating disorders are scarce.
Dalgleish and colleagues (Dalgleish, Golden, Barett et al., 2007) studied autobiographical memory functioning in 32 patients suffering from eating disorders and found that these patients are less specific on the autobiographical memory test then healthy controls. Laberg and Andersson (2004) studied autobiographical memory in a sample of 18 women recently treated for bulimia nervosa. Results showed that bulimic patients had difficulties retrieving specific memories and retrieved an excess of categoric memories. They also questioned the date of the retrieved memory. No differences between former patients and controls regarding the age of retrieved memories were found and both groups retrieved more distant events to negative cues than to positive cues. Nandrino Doba, Lesne et al. (2006) studied twenty-five restrictive anorexic girls. Their results indicate a higher percentage of general memories in anorexic patients compared to healthy controls. The authors also found that the longer the duration of illness, the higher the rate of general memories recalled for negative and positive cue words.
The goals of the present research were to study autobiographical memory functioning in girls suffering from anorexia nervosa, taking into account the duration of illness, the subjective evaluation of the pleasantness of retrieved memory, the date of the recalled memory and the level of depression. We hypothesized that girls with anorexia would recall fewer specific memories to emotional cue words than healthy control subjects. We presumed that the longer the duration of illness, the deeper the negative feelings connected to the disorder. Thus, memories recalled to cue words would be predominantly unpleasant and overgeneral. Because anorexic patients are extremely preoccupied with thoughts regarding food, body shape and weight, and the disorder is characterized by cognitive biases, it is possible that recalled memories to specific cue words be mostly from the period of illness.
Twenty-five inpatients from the Child and Adolescent Mental Health Unit I, Department of Pediatrics, Semmelweis University, Budapest, participated in the study. All patients had the restrictive type of anorexia (i.e., without binge eating, vomiting, or laxative abuse). Group characteristics are shown in Table 1. The mean age of the anorexic group was 15.34 years (SD=1.74; age range: 14-18 years). The control group consisted of 29 girls. They voluntarily participated in the study. All subjects were matched according to age and education level. The mean age of the control group was 15.27 (SD=1.25; age range: 14-18 years).
The Autobiographical Memory Test (AMT). The AMT was developed by Williams & Broadbent (1986). Participants are asked to provide specific memories in response to positive, negative and neutral cue words. Twenty-four cue words were printed on cards and presented to the participants: 8 positive words (happy, excited, sunny, joy, calm, tender, smile, hopeful); 8 negative words (misery, tragic, sad, upset, grief, ashamed, hurt, awful) and 8 neutral words (onion, ladder, pottery, grass, pianist, wildlife, bread, library). The words were presented in a fixed order, with positive, negative and neutral alternating. Before the words were shown, the participants were given the following instructions:
"I am interested in your memory for events that have happened in your life. I am going to show you some words. For each word, I want you to think of an event that happened to you which the word reminds you of. The event could have happened recently or a long time ago. It might be a trivial event or an important event. I also want you to make sure that the memory is for a specific event, so something that happened on a particular day at a particular time. For example if the word was 'good' it would be not OK to say 'I always enjoy a good party' because that not mention a specific event"
The researcher ensured that participants understood the instructions, and the experimental session did not begin until specific personal memories had been retrieved to three practice words (enjoy, friendly, bold). Participants were given 60 seconds to respond to each cue word. The first responses were coded as specific memories, general categoric or general extended memories, omission if participants exceeded the time limit or non-memories if their response was a semantic association. Participants were also asked to date their memories as accurately as possible on a scale from 1 to 6 and to score the retrieved memory as pleasant or unpleasent. Memories were categorized by two independent raters (both clinical psychologists). Inter-rater reliability using Cohen`s kappa was high: 0.98 for specific memories, 0.98 for categoric memories and 0.95 for extended memories. This was similar to inter-rater agreements reported by other authors (Brewin, Reynolds & Tata, 1999; Laberg & Andersson, 2004).
The Child Depression Inventory (CDI), (Beck et al., 1961) is a 27-item inventory which measures mood disturbance, somatic dysfunctions, social behavior and self-evaluation deficits. A score higher than twelve indicates depression.
The Eating Disorder Inventory (EDI) (Garner, Olmstead & Polivy, 1983) is a self-rating questionnaire, frequently used to evaluate eating attitudes and eating disorders. The inventory evaluates cognitive, emotional and behavioral factors and has eight subscales: drive for thinness, bulimia, body dissatisfaction, ineffectiveness, perfectionism, interpersonal distrust, interoceptive awareness and maturity fears.
Sessions took place on the hospital premises. Participants were tested individually, in a quiet testing environment, and all testing was carried out by the same experimenter. Ethical approval was obtained for the study. All participants were provided with a full explanation of the procedure and their right to drop out at any time. Written informed consent was obtained from participants who agreed to take part. Each participant was first administered the Autobiographical Memory Test. This was followed by the set of self-report questionnaires: The Child Depression Inventory, The Eating Disorder Inventory and a short questionnaire referring to demographic and anthropometric data.
Table 1 shows the results of the comparisons between the two groups. Significant differences were found between the body-mass index (BMI) and the mean weight of the two groups. The anorexic girls had a significantly lower BMI (Z=-4.51, U=102.000, p<.001) and a lower weight than the control group (Z=- 4.44, U=106.500, p<.001). Girls with anorexia had significantly higher scores on the CDI (Z=-3.70, U=149.500, p<.001) and on the EDI than the control group (Z=-4.96, U=76.500, p<.001).
Autobiographical Memory Responses
Participants' first responses to positive, negative and neutral cue words were analyzed. The Mann-Whitney test was used to assess statistical differences between the two groups. The median and the interquartile range (IQR, 25th to 75th percentile) of autobiographical memory types in patients and the control group are presented in Table 2.
The control group retrieved more specific memories compared to the patient group for each type of cue words: positive (Z=-5.21, U=67.500, p<.001); negative (Z=-5.09, U=73.000, p< .001) and neutral (Z=-5.84, U=28.500, p<.001). Patients retrieved more categoric memories than the control group for the negative (Z=-3.01, U=261.000, p<.001) and neutral (Z= -5.30, U=95.500, p<.001) cues. Patients also retrieved more extended memories than the control group for each type of cue words: positive (Z=-4.94, U=89.500, p <.001); negative (Z=- 5.22, U=75,500, p<.001) and neutral (Z=-3.62, U=163.000, p<.001). There were also significant differences in the number of no-memories (semantic associations), anorexic girls displaying a significantly higher number of semantic associations for each type of cue than controls (positive: Z=-3.05, U=243.500, p<.001; negative: Z=-1.96, U=278.000, p< .001; neutral: Z=-3.60, U=185.000, p<.001).
Memory Date and Rating of Pleasantness
Memory age for each retrieved memory was scored by the participants on a scale from 1 to 6: 1=less than one week since the reported event; 2= less than one month; 3= less than three months; 4= less than 6 months; 5= less than one year; 6= more than one year. Pleasantness was also scored by the participants, using a scale from 1 to 5: in the case of memories recalled for positive cues, 1 was the least pleasant memory and 5 the most pleasant one; for the memories recalled to negative cues, 1 indicated the least unpleasant event and 5 the most unpleasant event; for the memories recalled to neutral words, 1 indicated an unpleasant event, 3 a neutral event and 5 a very pleasant event. The median and the interquartile range (IQR, 25th to 75th percentile) of the memory date and the ratings of pleasantness are presented in Table.3.
We found significant difference between the control group and the clinical group in the memory age for neutral cues. The control group retrieved significantly older memories for neutral cues than the clinical group (Z=-2.03, U=264.500, p<.05). Pleasantness ratings were also significantly different in the case of neutral memories between the two groups. Girls with anorexia scored neutral memories as more unpleasant (Z=-3.12, U=202.500, p<.001).
No significant correlations were found in the patient group between CDI scores and the rate of specific memories or the rate of extended and categoric memories. Also, no significant relation was observed between the duration of illness and the number of specific memories recalled.
Discussion and Conclusions
The present study examines the autobiographical memory of patients with restrictive-type anorexia nervosa, taking into account the duration of illness, the subjective evaluation of the pleasantness of the memory, the date of the memory and the impact of depression on the retrieved memory type.
We hypothesized that there would be differences in the recollection of specific memories related to negative, positive and neutral cue words in the anorexic group compared to healthy controls. According to Williams (1996), patients with emotional disorders have problems with affect regulation and they adopt a less specific memory type as a coping strategy for regulating negative affect. Affect regulation is the ability of a person to reduce negative affective experiences and to generate positive ones. Williams asserts that the overgeneral memory style is a cognitive avoidance strategy, reinforced by the absence of painful emotions associated to painful memories. According to Karwautz (2001) anorexic patients often have difficulties with regulating emotions. They remain focused on negative emotional experiences, and they have no skills to cope with them. The overgenerality of autobiographical memory in eating disorders might be a cognitive and behavioral strategy to cope with negative affect. Research conducted with clinical samples suffering from eating disorders (Dalgleish, Tchanturia, & Serpell, 2003; Laberg & Andersson, 2004) shows that the autobiographical memory of anorexic and bulimic patients is characterized by overgenerality when compared to controls. Our results confirm previous findings, due to anorexic patients retrieving a greater proportion of categoric and extended memories and fewer specific memories than the control group for each type of cue word (positive, negative and neutral).
During the interviews participants were asked to date their memories as accurately as possible. The memory date was then scored on a scale from 1 to 6, as described in the results section. Our second hypothesis was that there would be differences between the anorexic group and the control group regarding the date of recalled memories, with anorexic patients recalling memories from their illness period and related to illness, and the control group recalling more distant memories. The eating disorders literature shows that these patients are extremely preoccupied with their problem, their attention is selective, focused on the illness and their memory functioning is biased (Carter et al., 2000; Davidson & Wright, 2002; Hunt & Cooper, 2001). There were no significant differences between the anorexic group and the control group regarding the date of the memories retrieved. On the average, patients recalled memories that were older than one year.
Participants were also asked to rate the pleasantness of the memory on a scale from 1 to 5, as described in the results section. The literature shows that anorexic patients are extremely focused on negative affect and they are dominated by a negative emotional state (Lask & Byant-Waugh, 2007). We assumed, as a third hypothesis, that patients would rate their memories, for the same type of cue, as more unpleasant than the control group. No such differences between the two groups were found for the positive and negative words. Most of the participants rated the negative events retrieved as being unpleasant or very unpleasant and the positive events as being pleasant or very pleasant. Anorexic girls rated neutral cues more pleasant than the control group. Laberg and Andersson's (2004) findings show that, compared to bulimic patients, normal controls assign a higher rate of pleasantness to memories retrieved for positive and negative cues.
Eating disorders are very often linked to depression (Swift, Ritholz, Kalin et al., 1986), with 50% to 70% of the eating disordered patients experiencing major depression (Halmi, Eckert, Marchi et al., 1991; Herzog, Keller, Sacks et al., 1992). We used the Child Depression Inventory to evaluate the depression level of our research group. Our fourth hypothesis was that a positive correlation would be observed between depression level (expressed in CDI scores), the duration of illness and the rate of specific memories recalled. No significant correlations were observed in any of these cases. Laberg & Andersson (2004) found a positive correlation between BDI scores and response latencies to cues; the higher the BDI score, the longer the response latency. Nandrion et al., (2006) found a positive relation between the number of general memories and illness duration. In our sample there was no relation between depression and autobiographical memory specificity, suggesting that this particular memory deficit is present in anorexia nervosa, but it is not a correlate of depression.
Our findings need to be considered while taking into account some limitations. We must first mention the small sample size, which does not allow definitive conclusions and the generalization of our results to the entire anorexic population. Another limitation of the study is the assessment of depression solely by the CDI. The use of a clinical interview (e.g., SCID) could prove useful in eliminating the subjectivity of the self-reported questionnaire. A larger sample and the use of clinical interviews to assess depression levels would allow comparing anorexic patients without depression with patients presenting depressive comorbidity. This way, we will have a better insight into autobiographical memory functioning in anorexia nervosa.
This study was supported by Domus Hungarica Scientiarium et Artium junior research scholarship, Hungarian Academy of Sciences.
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Tímea KOVÁCS (KRIZBAI)*1,2 , Pál SZABÓ1, Bea PÁSZTHY3
1University of Debrecen, Debrecen, Hungary
2Sapientia, Hungarian University of Transylvania, Târgu-Mures, Romania
3Semmelweis University, Budapest, Hungary
* Correspondence concerning this article should be addressed to:
Questia, a part of Gale, Cengage Learning. www.questia.com
Publication information: Article title: Reduced Specificity of Autobiographical Memory in Anorexia Nervosa. Contributors: Kovács , Tímea - Author, Szabó, Pál - Author, Pászthy, Bea - Author. Journal title: Journal of Cognitive and Behavioral Psychotherapies. Volume: 11. Issue: 1 Publication date: March 2011. Page number: 57+. © A.S.C.R. PRESS Sep 2008. Provided by ProQuest LLC. All Rights Reserved.
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