Salivary response to olfactory food stimuli in anorexics and bulimics

Appetite, 1988, 11, 15-25

Salivary Response to Olfactory Food Stimuli in Anorexics and Bulimics DANIEl. B. LeGOFF Department .:., Psychology, Simon Fraser University

PIERRE LEICHNER Faculty of Medicine, McGill University M. N. SPIGELMAN Department of Psychology, University of Winnipeg

Salivary response to olfactory food stimuli was assessed in controls and in anorexia

nervosa and bulimia in-patients before and after two months of treatment. Before treatment, anorexics salivated less then controls while bulimics salivated more than controls. Following treatment, the salivary responses of eating-disordered subjects were much closer to controls. Salivary response to food was correlated with measure of variability in caloric consumption. There may be two styles of dietary restraint: strict, unrelenting dieting, or the "dieting drone", exemplified by anorexic patients, and variable, "fence-sitting" dietary restraint, exemplified by .bulimic patients. It is suggested that this two-style theory is able to account for past contradictory findings of heightened or suppressed saliva flow rates in dieters.

INTRODUCTION

The nature of the impact of dieting on saliva flow rate has been a controversial topic. Wooley and Wooley (1981) review a great deal of research which shows quite clearly that low-calorie dieting decreases salivary flow rate in response to palatable food. Herman et al. (1981) provide equally convincing evidence that dietary restraint leads to a heightening of the salivary response to food. Wooley and Wooley explain their own findings, as well as those of other researchers, in terms of a Pavlovian inhibition model (Konorski, 1967). They report that subjects who scored high on the Dietary Restraint Questionnaire (DRQ, Herman & Mack, 1975) had lower saLivary responses to palatable food than did unrestrained subjects, following a low-calorie preload (150 kcal). They suggest that there is an.0ytive inhibition of the hunger response, represented by an "anti-hunger drive", which results from pairing food (conditioned stimulus) with caloriq deprivation (unconditioned stimulus) in a classical conditioning paradigm.

Address reprint requests to: Daniel B. LeGoff,Department of Psychology.Simon Fraser University, Burnaby, B. C. VSA 1SR, Canada. 0195--6663/88/040015 + 11 $03~0/0

© 1998 Academic Press Limited

16

D.B. Le,GOFF E T AL.

Wooley and Wooley point out the discrepancy between this finding (from Wooley et al., 1978)and that ofKtajner et al. (1981) who fo~,'nda heightened salivary response to

food in restrained as compared with unrestrained subjects. Wooley and Wooley suggest that these contradictory results are the result of different salivation collection techniques: Wooley et al. (1978) used a cotton dental roll absorption technique, while Klajner et al. (1981) "used a whole mouth suction procedure. They suggest that the technique used by Klajner et al. created anxiety in their subjects, which had an inhibitory effect on the normal flog rate of unrestrained subjects and a disinhibitory effect on the inhibited flow rate of restrained subjects. This explanation implies that the heightened salivary response to food found in restrained subjects by Klahner et al. was an artifact of their anxiety-provoking collection technique. Herman et al. (1981) disagree with this formulation and reply that the heightened salivary activity of restrained subjects is the result of greater hunger in these subjects; that is, "a heightened appreciation of--or readiness for--palatable food" (p. 357). These researchers argue that the contradiction between the findings of Klajner et al. and Wo01ey et al. may have resulted from differences in the subjects who were tested. Wooley et al. used subjects who were on strictly regimented diets, while the re~trained subjects of Klajner et al. were on self-monitored and therefore less strict diets. They suggest that this difference in strictness of diet produced the paradoxical findings. LeGoffand Spigelman (1987) provided evidence that supports the position of Herman et al., finding an increase in salivary respon'se to food in restrained subjects using the cotton absorption technique recommended by Wooley et al. LeGoff and Spigelman did not, however, address the hypothesis that different populations of dieters, that is, the "dieting drone" vs. the "fence-sitting dieter" (Herman et al., 1981, p. 360), could have been responsible for the disparate results. They tested only selfmonitored dieters and did not control for degree of diet strictness. The present study examines the hypothesis that different styles of dietary restraint ----consistent vs. sporadic--may account for differences in salivary responding to food--low vs. high, respectively. The hypothesis will be tested by comparing the salivary responses of two types Of eating-disordered patient, the restricting anorexic and the bulimic, with those of unrestrained controls. The patients in this study, in a sense, represent extreme forms of the inconsistent, sporadic dieter, and the consistent, invariable dieter. The restricting anorexic maintains an unrelenting self-control over eating and rarely, or never, succumbs to temptation (Garfinkel et al., 1977; Garfinkel & Garner, 1982). Bulimics, on the other hand, restrict their caloric intake in. a very irregular fashion, alternating high-calorie binges with periods of fasting, and/or purging via vomiting, laxative or diuretic abuse (Casper et al., 1980; Johnson et al., 1982; Schlesier-Stropp, 1986). It was predicted then, that compared to unrestrained controls, the bulimie patients should exhibit the heightened salivary response to food found by Klajner et al., as they exhibit the "fence-sitting" style of restraint. The anorexic patients, on the other hand, should salivate less to food than controls since their dieting is of the relentess variety which presumably characterized the restrained subjects of Wooley et al. These patients should exhibit the inhibited salivary response which Wooley and Wooley suggest is the result of consistent dietary restraint. It was further proposed that if the salivary response levels of eating-disordered subjects were a product of their dieting style, it should be possible to demonstrate that their salivary responses should become more like those of the control subjects when their eating habits were changed as a result of therapy. In other words, we expected to

SALIVATION IN ANOREXICS AND BULIMICS

17

find that while anorexics salivated less to food and bulimics salivated more to food than controls at the time they entered treatment, their responses should increase and decrease respectively to become more like unrestrained subjects after their eating patterns had become better controlled. Testing these hypotheses with this population is problematic because of the role that both anxiety and depression, two factors which adversely affect saliva flow rate, may play in the aetiology of eating disorders. It is also problematic that eatingdisordered patients are often treated with medications that have a deleterous impact on salivation (see Bassuk et al., 1984; Garfinkel & Garner, 1987). Attempts were made to rule out these possible confounding variables in the design and analysis of the research, described below. The present r~search was limited as well by the small sample numbers of eating disordered patients available for study. Nonetheless, the results provide fairly convincing evidence.

METHOD

Subjects The eating-disordered participants were six female anorexic and six female bulimic in-patients at the Health Sciences Centre Eating Disorders Clinic, Winnipeg, Canada, under the care of the second author. The control subjects were female students enrolled in an undergraduate psychology course at the University of Winnipeg. From a sample of 62 female subjects who had low scores on the short form of the Dietary Restraint Questionnaire (DRQ, Herman & Mack, 1975), 12 were selected who most closely matched the eating disordered sample on age, weight and height. The eating disordered subjects were simply the first six bulimics and six restricting anorexics who qualified for and agreed to participate in the study. Diagnoses of patients were made by the second author in accordance with DSM III criteria for anorexia nervosa and bulimi'a (American Psychiatric Association, 1980). Patientswith a mixed diagnosis of anorexia and bulimia (or anorexia with bulimie symptoms) were excluded from the study, as were subjects with a concomitant diagnosis such as depression or generalized anxiety disorder. Patients who were on medications which might interfere with saliva~'y responding (e.g., anxiolytics or antidepressants) or who reported problems with salivation (i.e., xerostomia), swollen glands or anosmia were also excluded. The age, height and weight of each of the patients as well as of their matched controls are reported in Table 1. Procedure Patients were first tested within 2 days of admission to the clinic, and were tested again after having been in the eating-disorders therapy programme for 60 days. Controls were also tested twice with a 60-day test-retest interval between first ~ihd second testing. Patients were tested individually in a small room on the psychiatric ward used by the Eating Disorders Clinic. University students were tested after the patients' data had been collected so that patients could be matched with controls for age, height and (excepting anorexics) weight. The students were tested individually in a small lab room in the Psychology Department at the University of Winnipeg. All subjects were tested 2 h after they had consumed their normal breakfast meal. Since the

18

D. B. LeGOFF ET AL. TAnLE 1 Age, height and weight for all patients and matched controls Controls (Bulimic-match)

Bulimic

Subject

Mean SD

Mean SD

Age (yr)

Height (cm)

Weight (kg)

Subject 1 2 3 4 5 6

17 24 37 23 21 18

168 157 173 155 163 165

52'5 54"4 54"8 53'0 58"9 56"2

23'3 7"2

163'5 6"7

55"0 2"3

19 25

Anorexic 157 170

36"2 47.6

1 2

20 19 16 26

175 155 165 170

54'4 35"8 45"8 42" 1

3 4 5 6

20.8 3"9

165.3 7.9

43.7 7.2

Age (yr)

Height (cm)

Weight (kg)

17 24 35 23 21 18

168 157 168 165 165 165

52'I 54"4 56'6 53'9 61"2 55'3

23"0 6'5

163"3 5"I

55"6 3"I

Controls (Anorexic-match) 19 160 47.6 24 163 49.8 20 19 17 27

175 157 163 165

56'6 45"3 49"8 52"I

21.0 3.7

163.8 6.2

50.2 3.9

research was designed to reflect differences in dieting patterns exhibited by a priori groups, no attempt was made to manipulate caloric content of meals. Within a testing session, participants were first asked to complete a questionnaire which assessed their current mood on the numbe'r categories 1 to 7, labelled from "not at all", to "very much", for each of the following adjectives: anxious, self-conscious, cooperative, comfortable, hungry, sad and angry. Only the "anxious" and "hungry" items were used in the analysis; the others were included so as not to suggest a particular emotional st'ate to the sfibjects. Three cotton dental rolls were then placed in the mouths of subjects, one below the tongue and one between the cheek and lower gum on each side.The subjects were then asked to close their eyes and to identify the aromas of a set of five food (taco-flavored corn chips, grape bubble gum, cinnamon bun, chocolate bar and salt- and vinegarflavored potato chips) and non-food odors (pencil shavings, clothing detergent, tobacco, pine needles and white vinegar) which were presented to them one at a time for 30 sec each. Total saliva collection time was 150 sec for each stimulus set. The odors presented were the same as those used in LeGoff and Spigelman (1987). In that project, a pre-study determined that the food odors were recognizable and produced a reliable increase in salivation in normal-weight unrestrained subjects. The non-food odors were shown to have no systematic effect on salivation Vinegar was included as a non-food odor because it was recognizable, readily available, and did not systematically affect salivation rate. A small amount of'each of the stimuli (15g) was placed in its own 100-ml opaque plastic bottle with an opening 2.5 cm in diameter. Salivation was measured once for each set of odors and the order of presentation of sets was counterbalanced both within subjects and across groups.

SALIVATION IN ANOREXICS AND BULIMICS

19

After subjects had responded to a set of odors, the dental rolls were removed and weighed on an electronic scale. Set weights were recorded to.the nearest 0.01.g. Following the saliva collection, participants completed the mood questionnaire again, this time to describe their emotional state during the salivation procedure. They then completed a short questionnaire in which they were asked to Sl~cify which of the ten odors they liked, which they disliked, which made them feel hungry, and which made them feel nauseous. Since ratings of non-food odors were not expected to relate in any systematic way with dietary restraint, only those food odors selected in each of these categories was used in the analysis. Following this, the subjects completed the DRQ,as well as the Eating Disorders Inventory (EDI: Garner et al., 1983) and Beck Depression Inventory (BDI: Beck et al., 1961). The EDI and the BDI are the most widely used clinical tools for the assessment of eating pathology and depression, respectively. The DRQ score was used as a measure of dietary restraint in order to provide direct comparability with both Wooley and Wooley and Klajner et al. The assessment of degree of eating pathology was recorded twice for this study, once at intake, and again after 60 days of treatment. A global clinical severity score from 1 (mild) to 9 (severe) was provided by the patient's attending psychiatrist, the second author, at both testing times. Scores on the EDI were~used as a second measure of clinical pathology and outcome. Eating style--that is, the variability of caloric content of meals--was assessed for all subjects by having them complete food diaries for 1 week prior to testing. A dietitian, blind to the hypotheses of the study, scored the diaries for reported caloric intake and rated them for variability of caloric content of meals. Each of the subjects' d/aries was rated from 1 (meals highly consistent in caloric content) to 10 (wide range of caloric content of meals). This caloric variability score was used as an index of "dieting drone" (low variability) vs. "fence-sitting dieter" (high variability) eating styles. Treatment Programme

The treatment of eating-disordered patients involved an eclectic in-patient programme which included individual and group psychotherapy, family therapy, cognitive therapy, behavioral monitoring and reinforcement and information therapy. The specific aspects of treatment were usually tailored to the requirements of individual patients. Data Analysis

A series of individual analyses were conducted in order to test the two central hypotheses of this study: (1) that anorexics would salivate less to food than controls while bulimics would salivate more; and (2) that anorexic and bulimic salivary responses would be more similar to those of controls following treatment. Group differences on salivary response both before and after treatment were assessed using t-tests. Further analyses included tests of group differences on caloric variability.(~qneway ANOVA) before and after treatment, and of the relationship between caloric variability and salivary response (regression analysis). Subjects' ratings of current state and of responses to food odors were also analysed in two separate ANOVAs. An attempt was made to rule out possible alternative explanations of the data by: (1) analysing BDI scores of anorexics and bulimics to discount the effects of differential depression (t-test), (2) comparing anxiety ratings of each of the groups to rule out group

20

D.B. LeGOFF ET AL.

differences in anxiety during testing (one-way ANOVA); (3) comparing degree of eating pathology of the eating disordered groups'based on clinical ratings, DRS and EDI scores before and after treatment (ANOVA), and (4) by assessing the degree of overall relationship between body weight and salivary response (regression analysis). Although it is unlikely that body weight would affect the dependent measure since it was taken as the difference between salivation to food and non-food stimuli, not all anorexics and their controls were matched on body weight (see Table 1), and this difference could be a confound. RESULTS As can be seen in Table 2 the anorexic patients, at the first testing session, salivated significantly less to food odors as compared with non-food odors than did bulimics, t = 5.21, p < 0'01. The anorexics also salivated less than did their unrestrain.ed controls, t-2.90, p<0.02. The bulimic patients salivated significantly more than did unrestrained matched controls, t = 2.29, p <0.05 (see Fig. 1). There was a significant variation among the four groups in the variability of caloric consumption reported in food diaries, F(3, 20) = 3.95, p < 0.05 (Table 2). This difference was primarily the result of the la~ge difference between anorexic and bulimic groups; the control group means on tlds variable were identical. Caloric variability was correlated with difference in flow rate between food and non-food odors over all subjects, r=0.58, p<0.01. At the second testing session there was no significant variation in salivary response among groups F(3, 20) = 1.5I,p > 0.24 (see Fig. 2).There was also no significam effectof group on variability of reported caloric consumption, F(3, 20)---1.72, p>0.19, and caloric variability was not related to salivary response to food, r=0.19,/#>0.25.

TABLE 2 Mean saliva flow rates to food and non-food odors and the salivary response differences, DRQ scores, EDI scores and caloric variability rating Bulimic Testing session Salivation to food (g/rain) Salivation to non-food (g/rain) Difference in salivation Dietary restraint score EDI score Caloric variability

T1

T2

Control (Bulimic-match) TI

~ 0.90 0.71 0"76 SD 0-15 0.14 0-17 ~ 0.37 0.37 0"41 SO. 0-16 0.09 0"14 X 0"53 0.34 0"35 SD 0.18 0.17 0.06 ~ 11.0 7"2 4.3 SD 1"5 1"5 0"5 ~ 91-3 41"3 29.5 SD 7"4 6"5 5.3 ~ 7-2 5-3 4.1 SD 1.6 1.8 1.3

T2 0"75 0-14 0.40 0"15 0.34 0.12 4.2 0.8 28.7 6"1 4.5 1.7

Anorexic TI

T2

0.55 0.67 0.06 0.08 0.43 0.44 0"07 0.II 0.13 0"23 0.05 0.07 11.2 8.2 1.5 1.5 85"5 43"7 11"4 7"6 2.8 5-1 1.4 0.7

Control (Anorexic-match) T1

T2

0"78 0.11 0.52 0"15 0"26 0.10 2.8 1"2 33.7 6.5 4.0 1.5

0"77 0.12 0.50 0"15 0"27 0.09 2'8 1"2 35"0 7"1 4.7 0.9

SALIVATION IN ANOREXICS AND BULIMICS

21

0"60

0-50

.E

0-40

E

0"30

o 0"20

0"10

8ulimic

Control Anorexic Control ( eulimlc- match} ( Anorexic- match)

FIGURE 1. Mean salivary response to food odors above baseline for bulimics, anorexics and matched controls at first testing.

0-50

0.40 I=

v

o~

>~ o

immi.mdll

0"30

IIIIIffllllllllll

![f!!fHHIIHJll i m l l l l l |

IIIJlfllllllJJHI IIIIJJlllllllllll

O'ZO

IflllllllllllllJl Ill IlJliJlJll t''''''''l

0.10

3ulimic

IIIIIIIIIIIII IIIIIIIIIIjll

IflllfjllJIII

IIIItllllllll

IIIII

Illlllllll[ll

IIIII]lllHll

Control Control Anorexic (Anorexic-match) (Bulimic- match)

FIGURE2. Mean salivary response to food odors above baseline for bulimics, anorexics, and matched controls at second testing.

22

D.B.

o

8

=

6

o co

2-

ET AL

LeGOFF

Illll[lll,

I00 ¢l

-o

80-

~5 g

60-

"~

40 20

12"E® o._~

I08-

o

42-

i .Bulimic Anorexic, Before t~eatment

.

Bul_irnic

Anorexic, After treatment

FIGURE 3. Mean global clinical rating, Eating Disorders Inventory score, and Dietary Restraint Questionnaire score for bulimics and anorexics before and after treatment. Both anorexic and bulimic patients improved in assessments of eating pathology after 2 months of treatment (Fig. 3). Anorexic patients had significantly lower global clinical ratings, t=4.21, p<0.01, and EDI scores, t=3.85, p<0.01. Bulimic patients also had significantly lower global clinical ratings, t=4.30, p<0'01, and EDI scores, t=3.23, p<0.01. DRQ scores also decreased significantly for anorexics, t=3.32, p<0.01, and for bulimics, t=4"23, p0-25. One-way ANOVAs also revealed significant group differences on number of Odors rated as "liked", F(3, 20)=6.64, p<0.01, and "made me hungry", F(3, 20)=16.40, p<0.01. Again, it appeared that this difference was the result of the small number of odors selected by the anorexic group at the first test. There were no differences between groups in odor ratings at the second testing session (p>0-1).

23

SALIVATION IN ANOREXICS A N D BULIMICS TABLE 3

Mean ratingsof hunger and anxiety before and aftersalivacollectionand mean number of odors rated as 'liked'and "made me hungry' Bulimic Testing session Hunger (before) Hunger (after) Anxiety (before) Anxiety (after) Odors 'liked' Odors'made me hungry'

Control (Bulimic-match)

Anorexic

Control (Anorexic-match)

T1

T2

T1

T2

T1

T2

T1

T2

~ 4.3 1.0 ~ 5.3 SD 1"9 ~ 1.2 SD 0.8 ~ 0.8 SD 0.8 ~ 4.7 SD 0.5 ~ 4.2 SD 0:8

4.8 0.8 6.2 0.8 1.0 0.9 0.7 0.8 4.6 0.5 4.2 0'7

4.5 1.0 6.0 0.9 1"3 1.2 1"3 1"0 4.5 0"7 4.0 0"6

4.3 1.2 6.2 0.8 1.3 1.0 1.3 0.5 4.7 0'5 4.3 0"6

2.5 1.1 2.4 1.1 0.7 1.0 0"7 0'8 3.2 1.2 1.7 0'8

4'0 0'6 4.3 0"8 0"8 0"8 0"8 0"7 3.8 1.7 3.3 1"2

4.3 1.2 5-7 0.8 0.7 1.2 0.7 0.8 4.7 0.5 4.2 0.8

4.8 0.8 5.7 1.0 0.8 0.8 0.8 0.8 4.8 1.3 4.3 0'5

SD

At neither testing session were there differences between the two groups of patients on BDI score, anxiety level before or after saliva collection, D R Q score or EDI score (p>0"l). There was a significant overall relationship between height/weight ratio and abovebaseline saliva flow rate to food at the first testing session, r = -0.34, p < 0.05. 1~[was also noted, however, that there was a strong relationship between height/weight ratio and caloric variability, r = - 0.42, p < 0.05. A partial regression analysis of the effects of both caloric variability and height/weight ratio on salivary response revealed that caloric variability accounted for the greater proportion of variance in salivary response, 27"5~o, while height/weight accounted for only 5.8~ of the variance, The dietary restraint score was not correlated with salivary response to food over all subjects, r--- 0.06, p > 0.25.

DISCUSSION The results reported above provide support for the notion that different dieting styles, described by Herman et al. as the "dieting drone" vs. the "fencd-sitting dieter", are associated with quite different salivary responses to food, and, by implication, with quite different hunger responses. Anorexia nervosa, patients, who were highly restrained in their eating style and reported little variability in caloric content of meals, salivated less to food than did unrestrained controls, matched for age, height and in some cases body weight. Bulimic patients, on the other hand, who were also high in dietary restraint but reported significantly more variability in caloric consumption, salivated more to food than did matched controls. Caloric variability accounted for a significant proportion of variance in saliva flow rate values; dietary restraint, unlike the

24

D.B. L,eGOFF ET AL.

results reported in LeGoff and Spigelman (1987) and Klajner et al. (1981) did not predict salivary response to food. It is evident then, that dietary restraint alone is insufficient to account for differences in salivary response to food in all types of dieters--two groups of subjects who were equally restrained had salivary responses to food that differed from those of controls in opposite directions. The proposal of Wooley and Wooley (1981) that long-term restraint may inhibit the normal hunger response is consistent with our finding of low salivary response in anorexics and also with the finding that anorexia nervosa patients rated themseves as significantly less hungry than did either the bulimic or control groups at the first (pretreatment) testing session. The anorexics also apparently liked fewer of the food smells and identified fewer of them as making them feel hungry. These collateral results suggest that it is in fact hunger which is inhibited in these patients, and not simply salivary response to food. The pre- post-treatment design of the present study yielded particularly convincing results. Anorexics and bulimics who engaged in a multimodal treatment programme for eating disorders were able to make significant changes in ra!ings of their eating styles and ia attitudes to food, body weight, and dieting. These changes were directly associated with changes in salivary response to food that could not be explained by changes in body weight, levels of anxiety, or levels of depression. That pattern strongly implies that dieting style as such has a substantial impact on hunger response. This study did have distinct limitations, however, and so the results should be to that extent interpreted cautiously. Firstly, the data are based upon small numbers of participants who were not sampled in a completely random fashion. Secondly, the patients who participated in the study were used as a clinical analogue, in a sense, of non-clinicaldieters. Although the eating patterns ofour clinical subjects and the people studied by Klajner et al. and Wooley et al. (1978) have similarities, there are a great many differences as well. It may well be that these populations are not at all comparable and the findings of this study are unique to eating-disordered populations. Nevertheless, the degree of agreement between our predictions, derived from nonclinical reports, and our findings is striking. It suggests that there are common underlying mechanisms. The implications of the present study, then, are threefold. First, there appear to be at least two important factors related to eating patterns which affect hunger as measured by salivary response to food odors: dietary restraint and dietary variability. Research in the past has focused on restraint alone and may have produced inconsistent findings as a result of not controlling for dietary variability. The contradictory findings of Wooley et al. (1978) and Klajner et al. (1981) may not have resulted from differences in their procedures as much as from differences in the dietary intake patterns of their subjects. Second, these results suggest that the aberrant eating patterns of anorexic and bulimic patients may be exacerbated by changes in hunger responsemanorexics becoming less hungry and bulimics more hungry as they adopt consistent or sporadic patterns of dietary restraint, respectively. In this way, the anorexic may find it even easier to control eating while the bulimic may find it progressively more difficult. Finally, the changes in degree of responsiveness to_food stimuli following treatment suggests thai the experience of hunger may be important to the etiology of these disorders, and that hunger response may be a useful prognostic and/or diagnostic indicator of eating pathology. Salivary, response, as an objective measure of hunger, may prove to be a useful tool for studying abnormal hunger and for exploring its causes and its cures.

SALIVATION IN ANOREXICS A N D BULIMICS

25

REFERENCES

American Psychiatric Association (1980) Diagnostic and statistical manual of mental disorders, 3rd edn. Washington, DC: American Psychiatric Association. Bassuk, E. L., Schoonover, S. C. & Gelenberg, M. D. (1984) The practitioner's guide to psychoactive drugs, 2nd edn. New York: Plenum. Beck, A. T., Ward, C. H., Mendelson, M., Mock, J. & Erbaugh, J. (1961) An inventory for measuring depression. Archives of General Psychiatry, 4, 561-571. Casper, R. C., Eckert, E. D., Halmi, K. A., Goidberg, S. C. & Davis, J. M. (1980) Bulimia, Archives of General Psychiatry, 37, 1030--1035. Garfinkel, P. E. & Garner, D. M. (1982) Anorexia nervosa; A multidimensional perspective. New York: Brunner/Mazel. Garfinkel, P. E. & Garner, D. M. (1987). The role of drug treatmentsfor eating disorders. New York: Brunner/Mazel. Garfinkel, P. E., Moldofsky, H. & Garner, D. M. (1977). Prognosis in anorexia nervosa as influenced by clinical features, treatment and self-perception. Canadian Medical Association Journal, I 17, 1041-1045. Garner, D. M., Olmstead, M. P. & Polivy, J. (1983) Development and validation of a multidimensional eating disorder inventory for anorexia nervosa and bulimia. International Journal of Eating Disorders, 2, 15-34. Herman, C. P. & Mack, D. (1975) Restrained and unrestrained eating. Journal of Personality, 43, 647-660. Herman, C. P., Polivy, J., Klajner, F. & Esses, V. M. (1981) Salivation in dieters and non-dieters. Appetite, 2, 356-361. Johnson, C., Stuckey, M., Lewis, L. D., & Schwartz, D. (1982) Bulimia; A descriptive study of 316 patients. International Journal of Eating Disorders, 2, 1-15. Klajner, F., Herman, C. P., Polivy, J. & Chhabra, R. (1981) Human obesity, dieting and anticipatory salivation to food. Physiology and Behavior, 27, 195-198. Konorski, J. (1967) Integrative activity of the brain. Chicago: University of Chicago Press. LeGoff, D. B. & Spigelman, M. N. (1987) Salivary response to olfactory food stimuli as a function of dietary restraint and body weight. Appetite, 8, 29-35. Schlesier-Stropp, B. (1986) Bulimia; A review of the literature. Psychological Bulletin, 95, 247257. Wooley, O. W., Wooley, S. C. & Williams, B. S. (1978) Appetite for highly and minimally palatable foods: Effects of deprivation. International Journal of Obesity, 2, 380 (Abstract). Wooley, O. W. & Wooley, S. C. (1981) Relationship of salivation in humans to deprivation, inhibition, and the encephalization of hunger. Appetite, 2, 331-350.

Received 13 November I987, revision 4 March 1988