Predictors of eating psychopathology in adolescent girls

Predictors of Eating Psychopathology in Adolescent Girls

Alison Wood, Glenn Waller and Simon Gowers

As part of a prospective study of the development of eating symptomatology, adolescent girls completed measures of eating attitudes and self-esteem. At two-year follow-up, the predictive validity of those measures was tested. Abnormul eating attitudes at baseline predicted both unhealthy eating attitudes and partial syndrome eating disorder (PSED) at follow-up. Poor self-esteem at baseline predicted unhealthy eating attitudes, but was not significantly associated with PSED. The results suggest that measures of both eating attitudes and self-esteem have potential value as screening instruments for subsequent eating problems, assisting in targeting intervention at an early stage.

INTRODUCTION

The difficulty of treating the eating disorders makes it important to intervene at as early a stage as possible. A shorter duration of symptoms is associated with a good response to treatment (e.g. Morgan and Russell, 1975). However, using physical characteristics alone, it is hard to identify cases until a marked degree of weight loss has occurred. Even assuming that such weight loss takes place, by the time that it is identified the sufferer may have already developed a physiological and psychological dependence upon starvation and bodily control, which reduces treatment compliance substantially (Slade, 1987).

Rather than relying on weight loss as a cardinal sign, there have been a number of efforts to identify psychological antecedents that might be associated with the development of eating disorders. A number of such antecedents have been proposed, including unhealthy eating attitudes, family function, and poor self-esteem. However, there has been little work to test the predictive validity of these measures. Eating disorders have a low prevalence, and the existing measures are imperfect. Therefore, such prospective studies require large-scale screening, and are likely to have a high rate of false positives and negatives at each data collection point. However, it remains possible to examine the ability of psychological variables to predict caseness, as long as more objective

CCC 1072-4133/94/010006-08 01994 by John Wiley & Sons, Ltd. and Eating Disorders Association

Eating Disorders Review Vol. 2 No. 1 (1994)

Predictors of Eating Psychopathology

measures (such as clinical interviews) are used to determine the presence of such caseness at the ‘predicted’ point. Patton et ul. (1990) demonstrated that a number of factors predicted the development of diagnosable eating disorders and abnormal eating attitudes at a one-year follow-up. Those factors included dieting and abnormal eating attitudes at the outset of the study, as well as a generalized measure of psychopathology.

Such predictive studies are most valuable when they consider more than the development of eating symptoms per se. Abnormal eating attitudes are undoubtedly important in the development of subsequent caseness, but it is necessary to identify the psychological factors that precede the abnormal eating attitudes themselves. This prospective study examines the ability of both abnormal eating attitudes and a non-eating factor (low self-esteem) to predict the later presence of abnormal eating attitudes and partial syndrome eating disorders (PSED-Button and Whitehouse, 1981). The study involves a two- year follow-up on a subsample of the adolescent girls described in an earlier report (Wood et al., 1992).

METHOD

Subjects

The subjects were 33 adolescent girls, drawn from the sample of 475 girls (the entire population of a private girls’ school) who participated in an earlier study of eating attitudes in adolescence (Wood et ul., 1992). The 33 were selected according to their earlier scores on the Eating Attitudes Test (EAT-26-Garner et al., 1982). Of the 475 girls in the initial sample, 24 remained in the school who had scored more rhan 22 on the EAT-26 at time 1 (the ‘high-risk‘ group). High risk was defined as having an EAT-26 score that was at least two standard deviations [ 8.091 above the mean score [6.60] for the whole group (i.e. above 22). These 24 were matched for age with 24 girls (the ‘low-risk’ group) whose initial scores on the EAT-26 were less than 15 (i.e. within one standard deviation of the mean score for the whole group).

Of this total sample of 48 girls, 37 agreed to take part in this follow-up study, two years later. However, only 33 girls actually attended for the follow-up assessment (16 from the ‘high-risk’ group; 17 from the ‘low-risk‘ group). In order to determine whether the non-attenders were likely to distort the findings, the girls’ characteristics a t the initial assessment (two years earlier) were considered. The 33 girls who attended for the follow-up were compared with the 15 non-attenders for their baseline age, height, weight, body mass index and EAT-26 scores, using independent t-tests. There were no significant differences between the groups, suggesting that the fact that a number of girls

7

A. Wood, G. Waller and S. Gowers

failed to attend did not reflect some initial difference in their levels of disturbance.

Measures and procedure

At the first data collection point (baseline), the girls completed a measure of unhealthy eating attitudes (EAT-26) and a measure of psychological variables that are proposed to be antecedents to abnormal eating (Setting Conditions for Anorexia Nervosa Scale- SCANS- Slade and Dewey, 1986). Of those two measures, the overall EAT-26 score and the General Dissatisfaction scale of the SCANS (a measure of poor self-esteem) were used to predict subsequent eating psychopathology. Higher scores on the SCANS and EAT-26 scales are defined as more ‘unhealthy’.

At the second data collection point (two-year follow-up) the girls were interviewed to establish the presence of eating problems. None of the girls had a diagnosable case of anorexia or bulimia nervosa. However, they were classified into three categories - non-dieters (ND), dieters (D), and ‘partial syndrome eating disorder’ (PSED)-using criteria devised by the first author (Wood, 1992) based on those used by Button and Whitehouse (1981). Those criteria are included in Appendix 1. The interviewer (AW) was blind to the girls’ earlier EAT-26 and SCANS scores when the follow-up interview was conducted. This ensured that decisions about whether the girls were categorized as PSED at follow-up were independent of any knowledge of the prior indices of psychopathology. Finally, the girls completed the EAT-26 again.

Data analysis

The two measures from baseline (EAT-26; Dissatisfaction) were used to predict both the EAT-26 and the presence of PSED at the two-year follow-up. The predicted measure of the EAT-26 at follow-up was treated first as a categorical dependent variable, comparing (through ANOVAs) the baseline scores of those girls who scored above or below the cut-off score ( > 20) proposed by Garner et al. (1982). Second, the EAT-26 at follow-up was treated as a dimensional variable, and was correlated with the EAT-26 and Dissatisfaction scores from baseline. PSED was also treated as a categorical independent variable (PSED versus ND/D). Its presence or absence at follow-up was used to compare (through ANOVAs) the girls’ EAT-26 and Dissatisfaction scores at baseline.

RESULTS

The findings of this study are based on the 33 girls attending follow-up assessment (16 from the high-risk group; 17 from the low-risk group). The mean

8


ages of the low- and high-risk groups at the baseline assessment were 13.9 years (SD = 1.26) and 14.1 years (SD = 1.33) respectively, and their body mass indices were 19.9 (SD= 1.87) and 21.5 (SD= 1.85) respectively.

Table 1 shows the mean scores for the girls on the two predictive measures from baseline (EAT-26; Dissatisfaction), according to the presence or absence of a partial syndrome eating disorder (PSED versus normal eating) at follow- up. Of the 33 girls, 12 were classified as PSED and 21 were normal eaters (ND and D groups) at follow-up. Similarly, Table 2 shows the EAT-26 and Dissatisfaction scores from baseline according to the absence or presence of an ‘at-risk’ EAT-26 score (< 20 versus > 20) at follow-up. Eight had ‘at-risk’ EAT-26 scores and 25 had low scores at follow-up. These levels of eating psychopathology are greater than those in the general population because of the selection criteria for subjects.

Table 1. Associations of unhealthy eating attitudes (EAT-26) and poor self-esteem (Dissatisfaction) at time 1 with presence or absence of partial syndrome eating disorder (PSED) at two0year follow-up (time 2)

Time 2 (two-year follow-up)

‘Diagnostic’ category ANOVA

Normal PSED F P

n 21 12 Time 1 (baseline)

EAT-26 10.5 28.2 17.3 0.001 (SD) (12.0) (11.1) Dissatisfaction 36.7 41.4 1.58 n.s. (SD) (6.60) (14.4)

Table 2. Associations of unhealthy eating attitudes (EAT-26) and poor self.esteem (Dissatisfaction) at time 1 with EAT-26 scores at two-year follow.up (time 2)

Time 2 (two-year follow-up)

EAT-26 category ANOVA

Low-risk High-risk F P ( < 20) ( > 20)

n 25 8 Time 1 (baseline)

EAT-26 11.1 28.8 15.7 0.001 (SD) (12.4) (11.9) Dissatisfaction 35.9 43.8 4.25 0.01 (SD) (6.44) (13.3)

9


Predictive validity of the EAT-26 Girls who were in the high-risk groups (PSED; high EAT-26) at follow-up had substantially greater EAT-26 scores at baseline. In addition, the EAT-26 scores on the two occasions were significantly correlated (r=0.690, p < 0.001). Therefore, the EAT-26 at first assessment predicted the EAT scores and the presence of PSED at two-year follow-up.

Predictive validity of Dissatisfaction (low self-esteem)

Girls who were in the high-risk group on the EAT-26 at follow-up had significantly greater Dissatisfaction scores at baseline. In addition, the two measures were significantly correlated (r = 0.424; p < 0.05). However, Dissatisfaction at baseline was not significantly greater in those who were in the PSED group at follow-up. Therefore, poor self-esteem at baseline predicted abnormal eating attitudes at the two-year follow-up, but did not reliably predict the presence of partial syndrome eating disorder.

DISCUSSION

These findings confirm that poor self-esteem and abnormal eating attitudes have some predictive validity in adolescent girls, since they are associated with eating psychopathology in later teenaged years. However, the degree of predictive validity is different across the two measures. Both were associated with later EAT-26 scores, but only the EAT-26 score predicted subsequent partial syndrome eating disorder.

The predictive validity of the EAT-26 suggests that unhealthy eating attitudes in adolescent girls are less transient than might be hoped. It is obviously too optimistic to simply dismiss abnormal attitudes to weight and bodily control as ‘a phase’. It is a matter of particular concern that the girls who had had relatively unhealthy eating attitudes at baseline were more likely to be in the category of PSED at follow-up. While PSED is not inevitably linked to the development of anorexia or bulimia nervosa, it can be seen as similar to at least the first stage of Slade’s (1987) model of the development of eating disorders. There is the obvious danger that any girl who has reached this stage is prone to see weight and body control as rewarding, and that she will then go on to develop a more robust disorder as a result.

It is possible that the Dissatisfaction scale is an indicator of ‘early’ or ‘potential’ eating psychopathology, and that two years was simply too short a period for poor self-esteem to have led to a sub-clinical eating disorder (although the data showed a trend in that direction). The effect of poor self-esteem on general eating attitudes might ‘percolate’ down to a diagnosable state over further years.

10


This prediction could be tested by a later follow-up measurement. Button (1990) has reported on the early stages of such a longitudinal study, aimed at considering the predictive power of poor self-esteem, to be followed up after four years. The present results suggest that self-esteem is likely to predict later eating psychopathology in that study.

The ability of poor self-esteem to predict subsequent eating problems (as predicted by Slade, 1982; Slade and Dewey, 1986) is of considerable importance. Slade (1987) proposes three ‘stages’ in an eating disorder, and stresses the importance of clinical intervention before the second stage (where weight and bodily control are highly reinforcing and hard to overcome therapeutically) becomes established. The use of measures of ‘non-eating’ psychological variables as predictors of unhealthy eating attitudes might allow for screening at an appropriately early juncture, so that intervention becomes substantially simpler (Slade, 1987). As well as demonstrating continuity over time in eating psychopathology, the present study has shown that poor self-esteem is one such ‘non-eating’ psychological variable. Further research is needed to determine whether other such variables would add to that predictive power.

APPENDIX 1-CRITERIA USED TO DEFINE CATEGORIES (ND/D/PSED)

Girls were asked questions about the following nine areas, and values of A, B, C or D were assigned to their answers according to the criteria outlined below. Where an answer was borderline, the classification erred towards the less pathological option. For items 6-8, ‘diagnostic criteria’ refers to DSM- 111-R criteria for the diagnosis of bulimia nervosa (American Psychiatric Association, 1987).

1. Weight-A. Within normal limits for age now and in the past; B. fluctuates by f 3 kg; C. has been significantly over- or underweight in the past (k 6 kg); D. > 25 per cent weight loss associated with restriction and/or bingeing and purging. 2. Preoccupation with weight-A. Minimal concern, does not weigh self more than once per week; B. concerned to maintain constant weight, restricts food reasonably, weighs self regularly; C. preoccupied with weight, takes priority over some daily activities; D. intense fear of weight gain. 3. Body image/sutisfaaion- A. Satisfied with body size/shape; B. moderately satisfied/few concerns; C. distorted body image/significantly dissatisfied with one or more body parts; D. grossly distorted body image, feels fat even when emaciated. 4. Dieting-A. Eats regular meals daily, usually with family; B. restricts food intake according to weight fluctuation, adherence to regime not rigid;

11


C. actively restricting calorie intake, constant dieting, guilt at eating fattening foods; D. gross reduction of food intake, secrecy. 5. Exercise--. Regular or none, prime aim is not weight control; B. regular exercise with aim of weight control; C. excessive/solitary exercise (> 1 h per day) with aim of weight control; D. addictive/obsessive quality to exercise, aim of weight control, impairment of other living activities. 6. Bingeing (large amounts of food consumed rapidly)-A. Absent; C. present bu t not to diagnostic criteria; D. present to diagnostic criteria. 7. Self-induced vomiting-A. Absent; C. present but not to diagnostic criteria; D. present to diagnostic criteria. 8. Use of laxatives, diet pills or diuretics-A. Absent; C. present bu t not to diagnostic criteria; D. present to diagnostic criteria. 9. Menstruation--. Present; D. primary or secondary amenorrhoea.

Non-dieters are those who receive a t least eight A’s. Dieters are those who receive fewer than eight A’s, and who otherwise score mainly B’s (i.e. not more than one C, and no D’s). Partial syndrome eating disorder (PSED) is defined by more than one C, and no more than one D.

REFERENCES

AMERICAN PSYCHIATRIC ASSOCIATION (1987). Diagnostic and Statistical Manual of Mental Disorders, 3rd edn, revised. Washington D.C.: American Psychiatric Association.

BUTTON, E. J. (1990). Self-esteem in girls aged 11-12: Baseline findings from a planned prospective study of vulnerability to eating disorders. Jolnrnal of Adolescence, 13, 407-413.

BUTTON, E. J. and Whitehouse, A. (1981). Subclinical anorexia nervosa. Psychological Medicine, 11, 509-516.

GARNER, D. M., Olmsted, M. P., Bohr, Y. and Garfinkel, P. E. (1982). The Eating Attitudes Test: Psychometric features and clinical correlates. Psychological Medicine, 12, 871-878.

MORGAN, H. G. and Russell, G. F. M. (1975). Value of family background and clinical features as predictors of long-term outcome in anorexia nervosa: Four- year follow-up of 41 patients. Psychological Medicine, 5, 355-371.

PATTON, G. C., Johnson-Sabine, E., Wood, K., Mann, A. H. and Wakeling, A. (1990). Abnormal eating attitudes in London schoolgirls- a prospective epidemiological study: Outcome at twelve month follow-up. Psychological Medicine, 20, 383-394.

SLADE, P. D. (1982). Towards a functional analysis of anorexia nervosa and bulimia nervosa. British Journal of Clinical Psychology, 21, 167-179.

12


SLADE, P. D. (1987). Early recognition and prevention: Is it possible to screen people at risk of developing an eating disorder? In: D. Hardoff & E. Chigier (Eds). Eating Disorders in Adolescents and Young Adults (eds D. Hardoff and E. Chigier). London: Freund.

SLADE, P. D. and Dewey,’ M. E. (1986). Development and preliminary validation of SCANS: A screening instrument for identifying individuals at risk of developing anorexia and bulimia nervosa. International Journal of Eating Disorders, 5 , 517-538.

WOOD, A. J. (1992). Abnormal eating attitudes amongst Manchester schoolgirls- A longitudinal study over two years. Unpublished M.Sc. thesis: University of Manchester.

WOOD, A. J., Waller, G., Miller, J. and Slade, P. D. (1992). The development of Eating Attitude Test scores in adolescence. International Journal of Eating Disorders, 11, 279-282.

Alison Wood, MBChB, MRCPsych, DRCOG, DCH, MSc (Addressee for correspondence) Department of Child and Adolescent Psychiatry, Royal Manchester Children’s Hospital, Hospital Road, Pendlebury, Manchester M27 IHA, U.K.

Glen Waller, BA, MClinPsychol, DPhil School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.

Simon Gowers, BSc, MBBS, MRCPsych, MPhil Department of Child and Adolescent Psychiatry, Royal Manchester Children’s Hospital, Hospital Road, Pendlebury, Manchester M27 4HA, U.K.

13

Documents

Predictors of eating psychopathology in adolescent girls