Adrenaline-induced hyperaggregability of platelets and enhanced thromboxane release in anorexia nervosa

Platelet aggregation and thromboxane A2 release in response to adrenaline and the relationship of this response to body weight was investigated in female patients with anorexia nervosa. Platelets obtained from patients with body weights below 75% of the expected average weight (Group I) showed significantly greater aggregation and TXA2 release in response to adrenaline when compared with controls matched for sex and age. Patients with body weights 75-95% of the expected average weight (Group II) did not show enhancement of platelet aggregation or TXA2 release. In Group I patients, platelet hyperaggregability and enhanced TXA2 release induced by adrenaline tended to normalise following inpatient treatment and weight gain: with 0.5 mumol/l adrenaline, the pre-weight gain median aggregation was 65%, whereas the post-weight gain value was 37% - P less than 0.01. Markedly underweight patients also had hyperaggregability following stimulation with ADP and collagen. This hyperaggregability also tended to normalise after weight gain but these changes were not statistically significant. Platelet hyperaggregability (especially in response to adrenaline) in anorexia nervosa is therefore secondary to weight loss and reverts to normal with normalisation of weight. These changes may reflect the previously documented increase in platelet alpha-adrenoceptors in thin patients with anorexia nervosa and their normalisation following weight gain. However, the hyperaggregability in response to agonists other than adrenaline suggests that an additional post-receptor mechanism may be involved.

Heparin-induced platelet aggregation in anorexia nervosa and in severe peripheral vascular disease

We have previously demonstrated that platelets obtained from patients with anorexia nervosa or severe peripheral vascular disease are hyperaggregable. Since conventional heparins are known to activate platelets in vitro and occasionally induce thrombosis and consumptive thrombocytopenia in vivo, we have investigated the direct effect of a conventional heparin on platelets obtained from patients with anorexia nervosa or severe peripheral vascular disease. Heparin at therapeutic concentrations was found to induce platelet aggregation of such platelets in vitro. In contrast, a recently developed low molecular weight heparinoid (Org 10172), at therapeutic concentrations, had no effect on these hyperaggregable platelets. We conclude that: heparin may be potentially harmful to patients with hyperaggregable platelets; thrombocytopenia and thrombosis associated with heparin therapy may be mediated through a direct effect of heparin on platelets; it is unlikely that heparin induced thrombocytopenia is always mediated by classical immunological mechanisms, especially in patients with hyperaggregable platelets; and low molecular weight heparinoids may be safer anticoagulants in patients with platelet hyperaggregability.

Life events, depression and hypothalamic-pituitary-adrenal axis function

The relationship between antecedent life events, clinical profile, and hypothalamic-pituitary-adrenal function was examined in 72 depressed patients. Antecedent life events were associated with first episodes of depression and with greater severity of illness, but their presence did not distinguish between patients diagnosed as endogenous or neurotic, and status on the dexamethasone suppression test was not associated with a greater or lesser likelihood of antecedent events. However, urinary free cortisol levels were higher in those patients with life events and difficulties.

Mood changes in bulimia nervosa

Daily measurement of mood, and the occurrence of specific eating behaviours, were assessed concurrently over an eight-week period in a sample of 50 patients meeting diagnostic criteria for bulimia nervosa. Results of observer-rated scales of mood showed a significant reduction of scores, whereas self-assessment of mood showed no change over the study period. Negative mood states, although not severe, were more marked when the specific behavioural symptoms of binge-eating, vomiting, or purging occurred, and they increased as abnormal eating behaviours accumulated. It is suggested that the accompanying dysphoric mood states of bulimia nervosa are likely to be a secondary manifestation related to the presence of abnormal eating symptoms, and that they do no constitute a primary depressive illness.

Endocrine changes and clinical profiles in depression: II. The thyrotropin-releasing hormone test

Thirty-one (43%) of 68 patients with primary depression were found to have a blunted thyroid-stimulating hormone (TSH) response to thyrotropin-releasing hormone (TRH). Increased thyroid activity, as measured by the free thyroxine index (FTI), was present in 16 (24%) of the patients. Patients with blunted responses had a higher mean FTI level than those with normal responses. Patients with blunted responses were significantly more likely to exhibit the symptoms of depersonalization, derealization and agitation. There was no clear association between blunting and any particular diagnostic category of depression. Patients with blunted responses and high FTI values were more likely to report significant long-term environmental difficulties than patients with blunted responses and normal FTI values. It is suggested that there may be more than one mechanism responsible for blunting of the TSH response in depressed patients. In some patients blunting may be due to negative feedback from increased output of thyroid hormones, possibly released as part of a stress response. In other patients blunting may be due to a different mechanism, possibly involving pituitary gland dysfunction. These mechanisms would not necessarily be mutually exclusive in any one patient.

Endocrine changes and clinical profiles in depression: I. The dexamethasone suppression test

Hypothalamic-pituitary-adrenal axis function was investigated in 72 patients with primary depression. Forty-four per cent of the patients demonstrated abnormal suppression of their cortisol levels after a 1 mg overnight dexamethasone suppression test. Patients with abnormal suppression ('non-suppressors') were not clearly distinguished from 'suppressors' by the commonly used diagnostic classifications. They did not appear to be more severely depressed, but they were more likely than the 'suppressors' to be in-patients. Multivariate analysis of the data suggested that two clinical features were independently associated with non-suppression: the PSE syndromes of Slowness and General Anxiety. However, the association of these syndromes with non-suppression was relatively weak, indicating that the clinical significance of the dexamethasone suppression test is, as yet, unclear. The results raise doubts about the validity of using the dexamethasone suppression test as a diagnostic marker for a specific depressive syndrome.

Platelet hyperaggregability and increased alpha-adrenoceptor density in anorexia nervosa

Plasma norepinephrine concentrations in a group of malnourished patients with anorexia nervosa were significantly (P less than 0.002) lower than those in an age- and sex-matched group of normal subjects. Platelet total alpha-adrenoceptor densities of these patients significantly (P less than 0.002) exceeded those of the controls. The increased total alpha-adrenoceptor density was due to an increase in the alpha 2-adrenoceptor receptor subtype, which mediates epinephrine-induced platelet aggregation. Accordingly, the aggregation response of the patients' platelets was significantly (P less than 0.002) enhanced after epinephrine challenge. We suggest that the starvation-induced fall in plasma norepinephrine levels is associated with the up-regulation of platelet alpha-adrenoceptors. This, in turn, accounts for exaggerated epinephrine-induced platelet aggregation in anorexic patients.

Screening for abnormal eating attitudes and psychiatric morbidity in an unselected population of 15-year-old schoolgirls

The Eating Attitudes Test (EAT) and General Health Questionnaire (GHQ) have been validated in an unselected population of 15-year-old South London schoolgirls. Scores on the questionnaires were compared with the results of standard interview. The EAT was found to be an efficient screening instrument for abnormal eating attitudes and behaviour, whereas the GHQ was less satisfactory in its ability to screen for psychiatric morbidity in this age group than in adults. At the optimal cutting points, 6.9% of this population gave a positive response to the EAT and 19.3% gave a positive response to the GHQ. There was a statistically significant positive correlation between the two sets of scores. Compared with their peers, girls giving a positive response to the EAT also reported that they missed more meals during the day and that their weight was more unstable.

Autonomic arousal in eating disorders: further evidence for the clinical subdivision of anorexia nervosa

Autonomic arousal, measured by skin conductance level and response, was examined in 36 female patients with eating disorders (anorexia nervosa and bulimia nervosa) and 32 control subjects. No differences were found between the control group and anorexics who lost weight solely through dieting (restricting anorexics). Patients with a diagnosis of bulimia nervosa and anorexics with bulimic features, however, showed fewer spontaneous skin conductance responses and were faster to habituate to 85 dB tones than either controls or restricting anorexic patients. The pattern of findings supports recent views concerning the clinical subdivision of anorexia nervosa.

Set-point displacement for behavioural thermoregulation in anorexia nervosa

1. The temperatures of thermal stimuli which evoked a feeling of maximal pleasantness upon contact with the hands of 14 malnourished patients with anorexia nervosa and 19 control subjects have been determined. A uniform skin temperature of 35 degrees C for all individuals studied was achieved by immersion of the subjects and patients in water at that temperature. Core temperatures of the anorexia patients were similar to those of the control subjects, but six of the patients preferred temperatures that were significantly higher than those of the control subjects. The thermal preferences of the remainder of the patients were similar to those of the control subjects. 2. The abnormally high thermal preferences of some of the anorexic patients could not be attributed to abnormal thyroid status, since values for serum free thyroxine measured in this group were similar to those obtained for the remaining patients. The abnormal responses persisted after there had been a substantial gain in the patients' weight and did not therefore appear to be directly due to malnutrition. 3. Elevation of deep body temperature produced an expected shift in preference towards lower stimulus temperatures in a sample of subjects from the control group, and in the patients who had initially preferred temperatures within the range of the controls. In the patients who had initially preferred abnormally high stimulus temperatures, however, hyperthermia produced little change in thermal preference. 4. It is suggested that an elevation in the set-point temperature for behavioural thermoregulation can occur in some patients with anorexia nervosa, and that this displacement may contribute to the distressing sense of cold which some patient experience.

Increased cutaneous vasoreactivity to cold in anorexia nervosa

1. Hand blood flows in healthy young men and women and in patients with anorexia nervosa were measured in a warm environment by using venous occlusion plethysmography. The mean core temperature of each of the three groups was similar, but the male control subjects and the anorexic patients had significantly higher peripheral blood flows than the female control subjects.

2. Blood flows were determined in the hand after 6 min localized cooling of it at varying temperatures. The female control subjects and the majority of the anorexic patients had blood flows which were similar for a given temperature, and lay between the higher values of the male control subjects and the low values of the remaining anorexic patients.

3. Those patients whose vascular responses to cold were exaggerated were characterized clinically by severe and persistent signs of ischaemia of the extremities during subsequent rehabilitation, unlike the majority of patients whose peripheral circulation rapidly improved.

4. Cold thermal stimuli evoked marked falls in blood flow of the contralateral (non-cooled) hand in the male and female control subjects, but these responses were attenuated or absent in the anorexic patients. An altered set-point for vasomotor thermoregulation in anorexia nervosa could explain these findings.

5. Plasma and whole-blood viscosity and erythrocyte deformability measured in a sample of the patients studied were similar to the values obtained from a sample of the control subjects.

6. It was concluded that the cutaneous vasoconstrictor responses to cold in the majority of the anorexic patients studied were quantitatively normal. The mechanism of the response, however, was different in that the vessels themselves were unusually reactive to cold. Increased cuteneous vasoreactivity to cold could contribute to the severe peripheral hypoperfusion observed in some anorexic patients.

Altered thresholds for thermoregulatory sweating and vasodilatation in anorexia nervosa

The changes in peripheral (hand) blood flow that occurred when deep body temperature was raised were measured in 13 patients with anorexia nervosa and 13 control subjects. The relation between blood flow and core temperature was shifted to the left in the patients with anorexia, with the onset of vasodilatation occurring at lower core and mean skin temperatures: no significant differences in the slopes of the responses were evident. The onset of thermal sweating occurred at lower core and mean skin temperatures in the patients with anorexia than in the controls. After ingestion of a high-energy liquid meal core temperature increased in the patients, and this was accompanied by a significant rise in peripheral blood flow in most cases. A similar meal in the normal subjects was followed by either no change in core temperature or a slight fall, and no consistent change in peripheral blood flow. These findings suggest that the lowering of thresholds for thermoregulatory sweating and vasodilatation may be a contributory factor to the abnormally low core temperature of patients with anorexia and may also explain some of their common complaints relating to feelings of warmth in the hands and feet after meals.

Amenorrhoea, body weight and serum hormone concentrations, with particular reference to prolactin and thyroid hormones in anorexia nervosa

Twenty women with anorexia nervosa were investigated at varying stages during weight gain. Basal prolactin and TSH and prolactin responses to TRH were normal and unrelated to body weight. LH, FSH and 17 beta oestradiol were low in emaciated patients and rose with weight gain. There was no correlation between serum gonadotrophin and prolactin concentrations. T3 and T4 concentrations were low but T3 rose with weight gain during refeeding over 4-6 weeks, whereas T4 remained low. A positive correlation was found between the TSH response to TRH and body weight. The abnormalities in the hypothalamic-pituitary-thyroid axis were similar to those seen in a variety of chronic illnesses and appear to be unrelated to the amenorrhoea. The failure of restoration of normal function at least after short-term refeeding requires further investigation. It was concluded that the amenorrhoea in anorexia nervosa is not associated with changes in prolactin secretion but is determined primarily by changes in the hypothalamic-pituitary-gonadal axis. These changes are induced largely by nutritional factors but psychological factors may also be involved.

Comparative double-blind trial of mianserin hydrochloride (Organon GB94) and diazepam in patients with depressive illness

1. The antidepressant action of mianserin was tested in a double-blind clinical trial lasting 6 weeks. Forty-six patients with moderate to severe degrees of depression were treated at random with mianserin or diazepam. Patients who failed to improve by week 3 were taken out of the trial. 2. Mianserin was more effective than diazepam in reducing scores on the Hamilton Rating Scale for depression. Fewer patients allocated to mianserin had to be withdrawn from the trial on account of failure to improve. Mianserin was more effective than diazepam in reducing symptoms of 'retarded depression' and as effective as diazepam in reducing symptoms of 'anxious depression'. 3. Mianserin did not cause any more side-effects than diazepam, very few side-effects being encountered with either drug. 4. The design of this trial on antidepressant drugs is commended on ethical grounds.

Assessment of the negative and positive feedback effects of administered oestrogen on gonadotrophin release in patients with anorexia nervosa

The capacity of the hypothalamic–pituitary axis to respond with changes in LH release to the negative and positive feedback effects of oestrogen was assessed in 19 patients with anorexia nervosa at different stages of the illness. Ethinyl oestradiol, 200 μg daily for 3 days, was administered and serial estimations of serum LH were carried out during and after the course of oestrogen.

In patients with anorexia nervosa tested when markedly underweight, negative feedback effects of oestrogen were demonstrated in those patients with detectable levels of LH. None of the patients demonstrated positive feedback release of LH to the oestrogen stimulus.

After the resumption of a more normal weight, basal LH levels were higher and negative feedback effects of oestrogen were observed in 11 out of 12 patients. The complete response to oestrogen with a subsequent positive release of LH to the oestrogen stimulus was shown by only 3 patients. Two of these 3 patients maintained a normal weight during the subsequent 6 months and both resumed regular menstruation shortly after the test. Three additional patients who had shown only negative feedback effects of oestrogen on LH release similarly maintained a normal weight and only 1 of them resumed menstruation, starting 3 months after the oestrogen test.

It was concluded that in recovery from anorexia nervosa there is a return of normal hypothalamicpituitary–gonadal activity in a definite sequence with recovery of the hypothalamus to respond normally to the negative feedback effects of oestrogen followed by return of the positive feedback capacity between oestrogen and LH which allows menstruation to resume. The resumption of normal hypothalamic–pituitary function is clearly dependent in part upon correction of the malnutrition. However, after correction of the malnutrition some patients fail to menstruate, and this appears to be determined by a continuing impairment of the hypothalamus to respond normally to the feedback effects of oestrogen upon gonadotrophin release.

The effects of clomiphene citrate on the hypothalamic-pituitary-gonadal axis in anorexia nervosa

Serum luteinizing hormone (LH) responses to a course of clomiphene citrate were studied in eleven patients with anorexia nervosa at different stages of the illness. In malnourished patients basal levels of LH were invariably low. With the resumption of a normal weight a small but definite rise in LH levels was observed but this spontaneous response to weight gain was variable in that many patients continued to exhibit abnormally low LH levels. The response to clomiphene in terms of a rise in basal LH levels after administration of the drug, followed by a second peak of LH and subsequent menstrual bleeding, was clearly dependent in part on the patient's nutritional state. In the malnourished state the response to clomiphene was usually either absent or incomplete. After the resumption of a more normal weight, the patients invariably showed an initial rise in LH after the clomiphene, but the second LH peak and subsequent menstruation were frequently not demonstrated. Six patients maintained a normal body weight for at least six months after a course of clomiphene, but only three of them resumed cyclical menstrual bleeding. It was concluded that factors additional to the nutritional state contribute to the prolonged amenorrhoea in anorexia nervosa and that clomiphene appears to have only a limited role in the treatment and management of patients with the disorder. Some aspects of current knowledge of the endocrine mechanisms that regulate normal menstruation and of the mode of action of clomiphene are outlined. The results of the present study are discussed against this background in an attempt to elucidate further the hypothalamic disorder underlying the amenorrhoea in anorexia nervosa.