An assessment of hypothalamo-pituitary-adrenal axis functioning in non-depressed, early abstinent alcoholics

Pergamon

Psychoneuroendocrinology, Vol. 21, No. 3, pp. 263-275, 1996 Copyright © 1996 Elsevier Science Ltd. All rights reserved Printed in Great Britain 0306-4530/96 $15.00 + .00

PII: S0306-4530(96)00001-7

AN ASSESSMENT OF HYPOTHALAMO-PITUITARYADRENAL AXIS FUNCTIONING IN NON-DEPRESSED, EARLY ABSTINENT ALCOHOLICS Alfredo Costa, Giorgio Bono, Emilia Martignoni, Paola Merlo, Grazia Sances and

Giuseppe Nappi Department of Neurology III, Neurological Institute C. Mondino, University of Pavia, Italy

(Received 28 March 1995; in final form 15 November 1995)

SUMMARY Chronic alcohol consumption has been shown to be associated with abnormalities in the regulation of the hypothalamo-pituitary-adrenal (HPA) axis in humans. However, conflicting data exist in the literature, with particular regard to studies performed in actively drinking or withdrawn alcoholics; in addition, the frequent presence of depressive disturbances in such patients may importantly affect the neuroendocrine findings. In this study, we investigated HPA function in 12 male alcoholics, in whom the presence of depression and other possible confounding factors was excluded, during the first and second weeks after cessation of ethanol intake. The plasma corticotropin (adrenocorticotropic hormone, ACTH) and cortisol levels in response to both a stimulation test with human corticotrophinreleasing hormone (CRH; 100 #g IV) and an insulin (0.15 UI/kg IV)-induced hypoglycaemia (ITI) were measured; the cortisol response to a standard overnight dexamethasone (1 rag) suppression test (DST) was also tested. While the mean baseline ACTH and cortisol levels, measured in the morning (0800-0830h), were not different from those of controls, ACTH and cortisol responses to the CRH test were markedly reduced (area of secretion p < .01 and p < .05, compared to controls). Similarly, the patient group showed an almost absent ACTH and cortisol release following insulin infusion (area of secretion p < .01 compared to controls, in either case). In four patients, non-suppression of plasma cortisol levels was seen on the DST, but no significant difference from normal suppressors was noted as far as the clinical features were concerned. These findings suggest that impaired hypothalamic and pituitary responsiveness, unrelated to depressive disturbances, occurs in recently withdrawn chronic alcoholics. While the possible influence of the alcohol withdrawal syndrome shoud be taken into account, such a pattern may be due to increased activity of the HPA axis, even in the face of preserved basal adrenal secretion. Whether these findings reflect a direct effect of sustained ethanol exposure on the components of the HPA axis, or a non-specific marker of impaired adaptation in chronic alcoholics, deserves further investigation. Copyright © 1996 Elsevier Science Ltd. Keywords---Alcohol; Withdrawal; HPA axis; CRH; ACTH; Cortisol; Dexamethasone; Insulininduced hypoglycaemia.

INTRODUCTION Studies conducted in humans under a variety of experimental paradigms have repeatedly suggested that chronic exposure to alcohol is associated with disturbances in the activity of Address correspondence and reprint requests to: Dr. A. Costa, Department of Neurology III, University of Pavia, Via Palestro 3, 27100 Pavia, Italy (Tel: 39 382 380206; Fax: 39 382 380286). 263

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the hypothalamo-pituitary-adrenal (HPA) axis. One of the most striking effects of sustained ethanol consumption, seen in relatively few patients, is the appearance of clinical features of hypercortisolaemia, earlier termed as alcohol-induced pseudo-Cushing's syndrome (Rees et al., 1977; Smals et al., 1976). On the basis of a substantial body of evidence from studies in laboratory animals (Guaza et al., 1983; Rivier et al., 1984), such changes have been attributed to the effect of ethanol on the HPA axis, although hormonal activation may be seen only with blood alcohol concentrations exceeding those commonly found in heavy drinkers. The possibility of acute ethanol stimulation of the HPA axis in non-alcoholic human subjects, reported by some authors (Jenkins & Connolly, 1968; Mendelson & Stein, 1966), has not been confirmed in subsequent, more accurate studies (Davis & Jeffcoate, 1983; Stott et al., 1987), and there is now general agreement that in normal humans ethanol per se does not increase HPA activity. Recent criticism has also suggested that ethanol may not directly affect the activity of the HPA axis in chronic alcoholics, the above clinical signs of hypercortisolism now being more correctly recognized as alcohol-associated Cushing's syndrome (Jeffcoate, 1993). Apart from the possible presence of cushingoid features, chronic alcoholic patients display several biochemical abnormalities shortly after withdrawal. Increased plasma or urinary cortisol levels, particularly during the first days or weeks, have been reported (Adinoff et al., 1991; Bannan et al., 1984; Heuser et al., 1988; Mendelson & Stein, 1966), while ethanol intake will suppress this response (Merry & Marks, 1972). By contrast, plasma and urinary cortisol levels in alcoholics who continue to drink heavily appear to be normal (Hasselbach et al., 1982). With regard to HPA axis dynamic regulation, in chronic alcoholics the cortisol circadian rhythmicity may be altered (Adinoff et al., 1991; Rosman et al., 1982) and corticotropin (adrenocorticotropic hormone, ACTH) response to both hypoglycaemia and corticotrophin-releasing hormone (CRH) administration is reduced (Adinoff et al., 1990; Berman et al., 1990; Chalmers et al., 1978; Rosman et al., 1982; yon Bardeleben & Holsboer, 1988), this also being the case in recently detoxified patients (Heuser et al., 1988), despite different observations by other authors (Bailly et al., 1989). Finally, the most consistent finding in alcoholics is the reduced sensitivity to PO or IV dexamethasone (Fink et al., 1981; Kirkman & Nelson, 1988; Miiller et al., 1989; Swartz & Dunner, 1982), although in some instances withdrawal itself may have affected the results, as it is known that the response to dexamethasone is altered during abstinence (Oxenkrug, 1978). Several variables thus appear to be critical in evaluating HPA regulation in alcoholics, and methodological differences related to the absolute amount of ethanol, duration of alcohol intake (acute vs. chronic), method of administration and particularly the peculiar conditions of the population studied (active drinking vs. alcohol withdrawal) may have generated inconsistencies in the literature. Another variable resulting in important limitations is the high prevalence of depressive disturbances in alcoholics (Ross et al., 1988), which may have affected the results of previous studies, although HPA abnormalities have also been described in non-depressed patients (Berman et al., 1990). Finally, the complex psychosocial context of alcoholism, with its considerably stressful environmental demands (Atkinson, 1985), may itself contribute to changes in HPA activity. The present study was therefore designed to evaluate further the effects of chronic alcoholism on the activity of the HPA axis. Compared to previous studies, the potentially confounding variable of depression was ruled out, and the investigation extended such as to assess the hypothalamic as well as pituitary responses to neuroendocrine challenges in the

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same group of patients. To this purpose, in a selected group of chronic alcoholics undergoing a controlled withdrawal programme, we measured plasma ACTH and cortisol levels during a CRH stimulation test and an insulin-induced hypoglycaemic test (ITF); the cortisol response to an overnight dexamethasone suppression test (DST) was also investigated.

MATERIALS AND METHODS

Subjects Twelve chronic alcoholic patients, presenting to the Department of Neurology III of the University of Pavia for short-term withdrawal treatment, were included in the study. All patients claimed that they had not drunk less heavily prior to hospitalization, and that their latest drink was within 24 h from admission. Patients taking barbiturates, anticonvulsants or other drugs known to interfere with adrenocortical function were excluded from the study. After approval of the local Ethical Committee, written consent was obtained from patients upon full information on the procedures of the study. A standard interview was completed on the first hospital day and included, among others, questions on the duration of regular drinking and daily drinking, intake of alcohol over the past years and incidence of alcohol abuse and depressive illness in relatives. The mean _+SD age of patients was 53.4 _+5.9 years (range 42-60), and their mean body weight 69.2 _+4.4 kg (range 64-80). The mean _+SD duration of alcohol abuse was 27.1 _+9.5 years (range 6--40). The daily intake of alcohol ranged between 100 and 700 ml of the equivalent of absolute ethanol. The diagnosis was made according to the Research Diagnostic Criteria (RDC) (Spitzer et al., 1978) and the DSM III-R (American Psychiatric Association, 1987). All patients met RDC requirements for definite alcoholism and DSM III-R criteria for alcohol dependence. None of the patients had a history of drug abuse in addition to alcohol. Medical illness (including hypertension) was ruled out by complete physical examination and laboratory tests. In all patients the serum levels of liver enzymes sGPT, sGOT and cholinesterase were within their normal laboratory ranges (0-31, 0-31 and 4300-11,300 U/l, respectively). Gamma-glutamyl transferase levels were over the normal range (7-32 U/l) in 10 of the 12 patients (mean _+SD 164.2 _+204.2). No patient showed evidence of nutritional deficiency. Eight patients complained of occasional sensory disturbances of lower limbs, and electromyographic evaluation showed mild signs of alcoholic neuropathy. None of the patients was clinically depressed on admission, as assessed by clinical interview. In all patients the score of the Hamilton Rating Scale for Depression (HRSD) (Hamilton, 1960) was less than 18, whereas the mean _+SD score of the Hamilton Rating Scale for Anxiety (HRSA) was 27.1 +_4.6 (range 24-38). In addition, none of the patients had a personal history of depressive episodes, whereas all had a family history of alcoholism; only two patients had first-degree relatives with depressive disturbances. In all patients a standard brain CT scan was performed, and in eight of the 12 patients signs of mild to moderate cortical atrophy, mostly evident at the subtentorial level, were observed. Each patient underwent an extensive battery of neuropsychological tests, which excluded the presence of dementia in all cases. In particular, the mean _+SD Mini Mental State (MMS) value was 27.6 _+ 1.4 (range 25-30). Ten age-matched male volunteers (mean _+SD age 48.7 _+6.9 years, range 38-62) served as control subjects. They were normotensive and had no cardiovascular, hepatic, renal or endocrino-metabolic diseases; subjects were also free of past or present DSM-III axis I or II diagnosis. None of the volunteers was drinking alcohol during the course of the study.

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On admission, patients were allowed for 3 days a controlled daily intake of alcohol (red wine) of 500 ml (12% volume of ethanol) before interrupting alcohol consumption. Mild withdrawal symptoms were reported by five patients only during the first days, and were controlled by the administration of bromazepam (3-6 mg/day PO) or alprazolam (1.5-3 rag/ day PO).

Neuroendocrine Testing Tests were performed during the first and second weeks from admission, when any benzodiazepines had been discontinued for at least 2 days to avoid interference with HPA activity. The CRH test was done first; DST and ITT followed by an interval of at least 24 h between tests. During the CRH and I T r tests, the subjects were resting in bed in the investigation ward, while their heart rate and blood pressure values were continuously recorded using a vital sign monitor. On the morning of each test, after an overnight fast, between 0800 and 0830h an IV forearm cannula was inserted; the basal sample was always drawn after at least 30 min, to allow hormonal changes associated with venipuncture stress to subside. The cannula was kept patent by the infusion of saline solution. In the CRH stimulation test, human CRH (Corticobiss, Bissendorf Peptide GmbH, Germany; 100/~g) was administered IV over 1 min, and blood samples for ACTH and cortisol determination were collected immediately before and 15, 30, 60 and 120 min after human CRH injection. In the ITT, subjects were given insulin (Actrapid, Novo, Italy; 0.15 IU/kg) as an IV bolus. Blood samples for glucose, ACTH and cortisol determination were obtained basally and 15, 30, 45, 60, 90 and 120 min after insulin administration. The DST involved the administration of dexamethasone (Decadron, Merk, Sharp & Dohme, Italy; 1 mg) at 2300h, and blood sampling on the following day at 0800 and 1600h for ACTH and cortisol determination. In conformity with the most used standards, the result was scored as abnormal (non-suppression) when patients showed cortisol values equal to or greater than 50 ng/ml at either time following dexamethasone (Carrol et al., 1981). In all tests, after discarding the first 2 ml, blood for ACTH and cortisol measurement was collected in cooled heparinized plastic tubes containing 1000 UI/ml aprotinin (Trasylol, Bayer, Switzerland) and centrifuged at 2500 rpm for 10 min at 4°C. Plasma was then stored at - 2 0 ° C until assay. Immunoreactive ACTH and cortisol were measured in duplicate by radioimmunoassay using commercially available kits (Technogenetics, Italy). The inter- and intra-assay coefficients of variation were 6.5% and 3% for cortisol, and 10% and 5% for ACTH, respectively. Statistics Statistical evaluation was performed using analysis of variance with repeated measures, with the baseline value as a covariate (MANCOVA), followed by Duncan's post hoc test, where appropriate. ACTH and cortisol responses to CRH and hypoglycaemia are expressed as either absolute values or the net integrated area under the curve (AUC) of hormone secretion. This was calculated as the area beneath the concentration-time curve from 0 to 120 min, minus the area corresponding to the baseline value, x 120 min. Values are expressed as mean _+standard error of the mean (SEM), unless otherwise stated. Significance is taken as p < .05.

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RESULTS Baseline Hormone Levels

Morning plasma ACTH levels obtained in basal conditions were 78.5 _ 6.2 pg/ml in the alcoholic group and 85.2_ 6.9pg/ml in control subjects during the CRH test, and 87.3_ 6.4 pg/ml in alcoholics and 83.6_ 10.0 pg/ml in control subjects during the ITT, without significant differences between groups in any case. Similarly, no differences were observed between groups with regard to cortisol baseline values: alcoholics 90.2 +_.9.9 ng/ ml, controls 78.7 _ 7.2 ng/ml during the CRH test; alcoholics 89.1 _ 6.8 ng/ml, controls 106.1 _ 9.9 ng/ml during the IT-F; alcoholics 96.7 _ 8.0 ng/ml, controls 81.4 _ 6.4 ng/ml prior to dexamethasone intake.

C R H Test

Figure 1 shows the mean absolute values of ACTH throughout the CRH test. Only control subjects showed the expected ACTH response to the administration of the releasing factor (MANCOVA, group-time interaction, df = 3,51, F = 27.40, p < .0001). Hormone levels showed a significant increase after 30 min and a peak after 60 min (both p < .01 compared to baseline values); by contrast, in alcoholic patients a markedly reduced response was seen, with a non-significant increase after 30 min. Similar results (Fig. 2) were obtained for plasma cortisol (MANCOVA, group-time interaction, df = 3,54, F = 12.18, p < .0001), whose values increased significantly only in control subjects after 30 and 60 min (p < .01 in either case, peak after 60 min). As shown in Fig. 3, the integrated AUCs for ACTH and cortisol secretion were significantly higher (t9 < .01 and p < .05, respectively) in controls (ACTH 6964.3 _+739.2 pg/ml x 120 min; cortisol 7076.7 _ 580.4 ng/ml x 120 min) than in

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the patient group (ACTH 281.8 _+559.5 pg/ml x 120 min; cortisol 1338.2 +_1164.4 ng/ml × 120 min). ITT All patients and controls became adequately hypoglycaemic (glucose values < 40 mg/dl) following insulin administration. The maximum decrease in blood glucose levels was concomitant (after 30 rain) and superimposable in the two groups (32 +_3 mg/dl in alcoholics and 34 _+2.5 mg/dl in controls). As shown in Fig. 4, the ACTH response to hypoglycaemia was considerably higher in control subjects (MANCOVA, group-time interaction, df = 5,54, F = 22.70, p < .0001), with a significant increase over the baseline levels 45 min after insulin infusion and a peak after 60 min (both p < .001). Alcoholics showed a non-significant peak after 60 min. Similarly, cortisol values (Fig. 5) were higher in the control group throughout the test (MANCOVA, group-time interaction, dr= 5,54, F = 10.92, p < .0001), with a significant increase 60 min after insulin and peak after 90 min (p < .01 and p < .001 vs. baseline values, respectively). The mean cortisol response in alcoholics was found to be almost absent. Figure 3 shows the secretory AUC for ACTH (7232 _+769.3 pg/ml x 120 min in controls and 461 _+620.2 pg/ml × 120 min in alcoholics, p < .01) and cortisol (6397.6 +_1584.7 ng/ml × 120 min in controls and 208.5 _+1204.0 ng/ ml x 120 min in alcoholics, p < .01) during the ITF. DST On the day after dexamethasone administration, all control subjects had cortisol levels well below the cut-off value of 50 ng/ml at either 0800 or 1600h (data not shown), whereas four of the 12 alcoholic patients showed cortisol values over 50 ng/ml at either time (Fig. 6).

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Fig. 6. Individual plasma cortisol levels during overnight dexamethasone suppression test in 12 chronic alcoholics. Solid circles represent non-suppressors at 0800 and 1600h on the day following dexamethasone intake (POST-DEX). The four non-suppressors were those exhibiting the highest predexamethasone (PRE-DEX) cortisol values (solid circles). The dashed line refers to the standard cutoff value of 50 ng/ml.

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Notably, these patients were those exhibiting the highest pre-dexamethasone cortisol levels, and although their mean value (121.8 _+13.2 ng/ml) tended to be higher than that of the remaining eight patients (84.2 _+6.8 ng/ml), the difference between groups did not attain statistical significance. Moreover, there was no difference between non-suppressors and normal suppressors with regard to their previous individual ACTH and cortisol responses to CRH, ITT and other clinical parameters, such as age, duration of alcohol abuse, daily intake or body weight.

DISCUSSION The present findings suggest that in chronic alcoholics who are abstinent for 3-9 days the baseline ACTH and cortisol levels do not differ from those of control subjects, but fail to increase in response to either CRH or hypoglycaemia. In addition, cortisol non-suppression appears to occur in 30% of patients, in the absence of demonstrable differences from the remaining normal suppressors in the clinical parameters. To our knowledge, this is the first study in which the CRH test, ITT and DST were performed in the same group of alcoholics, once the possible influence of depressive symptoms and other known confounding factors (medical disorders, malnutrition, medications or other drug abuses) had been ruled out. In acutely withdrawn patients, the presence of hypercortisolism has been noted (Adinoff et al., 1991; Bannan et al., 1984; Heuser et al., 1988), while in our study, at least in the morning, cortisol levels were similar to those of controls on three different occasions. These findings are in accordance with other observations (Adinoff et al., 1990; Loosen et al., 1991), and in any case the fact that withdrawal in our patients was not abrupt may explain the lack of increased cortisol levels. However, it is not possible to exclude that even under a programme of progressive restriction of alcohol intake hypercortisolaemia may have occurred in our patients during the first 3 days. It should also be borne in mind that differences in the baseline ACTH and cortisol values were very large in magnitude, and the relatively small size of the study groups may have influenced the results. The observed reduced ACTH response to CRH administration is in agreement with previous studies in actively drinking (Wand & Dobs, 1991), acutely withdrawn (Adinoff et al., 1990; Chalmers et al., 1978; Heuser et al., 1988) and medium-term abstinent (Holsboer et al., 1987; Loosen et al., 1991) alcoholics. In the latter study, however, cortisol levels in response to ovine CRH were normal, suggesting a sufficient adrenocortical response even in the face of reduced ACTH release, whereas in the study by Wand and Dobs (1991) adrenal response to ACTH infusion also appeared to be decreased. Certainly, the different modes of stimulation, the different dose and nature of CRH (ovine vs. human), the sometimes unspecified duration of abstinence and the variability of protocols of alcohol withdrawal render it difficult to compare the findings mentioned above. On the other hand, an excess in HPA drive, reported in the above studies and expressed by the increased cortisol secretion during the first days of withdrawal, may still account for the reduced ACTH responses observed by us. While a decreased ACTH resPonse to CRH has been consistently observed in patients with major depression (Gold et al., 1986; Holsboer et al., 1984), this pattern was associated in most cases with increased basal cortisol levels, suggesting that the response of pituitary corticotrophs to exogenous CRH was significantly restrained by glucocorticoid-negative feedback. In the present study, alcoholic patients were free of actual or previous depressive disturbances and, despite reduced ACTH and cortisol response to CRH, their baseline (morning) cortisol levels were similar to those of control subjects. The significance of this

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finding is unclear; however, one explanation may be that proposed by Adinoff et al. (1990), according to which a recent hypercortisolaemic state, due to hypertrophy of the adrenal cortex, may lead to a persistently reduced pituitary response to CRH, even in the presence of normalized cortisol levels. This would also be consistent with the observation that corticosterone administration in the rat attenuates more potently the stimulated rather than the basal ACTH release (Keller-Wood & Dallman, 1984). In another study (Loosen et al., 1991), the adrenal cortex appeared to be hyperresponsive to the small quantities of ACTH secreted in response to CRH, suggesting that the primary defect in alcoholism may take place at the pituitary level. Indeed, another possibility is that in alcoholics the pituitary corticotrophs may be damaged by the prolonged exposure to alcohol, which would agree with previous in vitro studies (Rivier et al., 1984). On the other hand, repeated CRH tests in alcoholic patients after withdrawal (1 and 3 weeks) have shown progressively increasing pituitary responses to the releasing hormone, possibly due to attenuation of the toxic effects of ethanol (Adinoff et al., 1990), whereas others have suggested that ACTH (but not cortisol) response to CRH may remain reduced, even after a 10-month abstinence (Holsboer et al., 1987). The possibility also exists that the combined effects of long-term overexposure and subsequent withdrawal(s) may precipitate neurochemical changes in the CNS, ultimately impinging on HPA regulation. In any case, as pointed out by Jeffcoate (1993), the effect of alcohol on the pituitary may be a non-specific one, since a clear ACTH-suppressive action would clearly argue against any possible role for alcohol in pseudo-Cushing's syndrome. A possible overdrive of endogenous CRH, resulting in decreased pituitary sensitivity, may also explain the reduced ACTH release in alcoholics, similar to what was proposed earlier for major depression (Nemeroff et al., 1984). However, it is of note that in chronic alcoholics the cerebrospinal fluid CRH levels, which-should mirror the hypothalamic peptide content, have been found to be similar to those of normal controls (Adinoff et al., 1990). Dave et al. (1986) have also shown that ethanol exposure in the animal induces a reversible decrease of CRH content in the hypothalamus. Accordingly, in alcoholic patients CRH drive may be lower as long as they drink ac'fively, and increase at the time of withdrawal as a rebound phenomenon, resulting in reduced pituitary sensitivity. ITT is an established neuroendocrine tool which, at variance with CRH acting on the pituitary, is thought to stimulate the HPA axis at the hypothalamic level (Aizawa et al., 1981). A decreased cortisol response to ITT in alcoholics was reported in early studies (Chalmers et al., 1978; Merry & Marks, 1972), and the blunted growth hormone increase after insulin seen in the latter study suggested that in alcoholics the neuroendocrine abnormalities may not be confined to the HPA axis alone. Similarly to the CRH test, a reduced HPA response to insulin has also been observed in primary affective disorders (Holsboer et al., 1987), suggesting that this pattern is not specific to alcoholic patients, and that alcoholism and depression may share a common psychobiological terrain. Our findings in alcoholics are consistent with the studies mentioned and with others in both recently detoxified (Knudsen et al., 1987) and actively drinking patients (Berman et al., 1990), although in the former case a normal cortisol response to ACTH was observed, and in the latter the plasma cortisol values, as opposed to ACTH, were within the control range. Such discrepancies suggest that the separate investigation of the adrenal, pituitary or hypothalamus may provide incomplete information, and that studies should be extended to consider the HPA axis in its entirety. While ITT abnormalities would suggest a primary hypothalamic disturbance in alcoholics, an additional direct effect of chronic ethanol on the adrenal gland has also been hypothesized (Berman et al., 1990). In this study, we were

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unable to find any significant increase in plasma cortisol levels following insulin infusion, suggesting that the low ACTH levels observed during the test may not be sufficient to cause an adequate adrenal response. Therefore, this finding does not support the presence of adrenal hyperresponsiveness in our alcoholics, although an ACTH stimulation test would probably have been of particular interest in this respect. The observation of abnormal response to dexamethasone in 30% of our patients, suggesting that feedback mechanisms may be disrupted in a significant number of cases, is in accord with several previous reports (Fink et al., 1981; Miiller et al., 1989; Swartz & Dunner, 1982). The variety of factors potentially affecting DST outcome, including psychosocial stress, is well known, and it has been long known that overnight DST results in false positives in as many as 20% of cases. In the particular case of alcoholic patients, the possibility exists that the metabolic clearance rate may be altered and thus affect dexamethasone elimination. The lack of information regarding dexamethasone levels in this and other studies represents a major shortcoming, although liver function appeared to be substantially preserved in our patients. In the same test, we were unable to demonstrate the pre-dexamethasone hypercortisolaemia found in such patients by others (Smals et al., 1976; Rees et al., 1977); however, similarly to what was reported in depressed patients (Schlesser et al., 1980), in the four patients showing non-suppression we observed average predexamethasone cortisol levels higher (although not significantly so) than those of normal suppressors, while no differences from normal suppressors were found as far as their clinical features were concerned. In the above-mentioned studies showing pre-dexamethasone hypercortisolaemia, DST was performed soon after the admission of patients, and the treatment for withdrawal was not specified. By contrast, in other studies performed days after cessation of drinking, the plasma cortisol levels were found to be normal (Oxenkrug, 1978). Similarly, in the present study patients were abstinent for 7-8 days at the time of DST, and this may have attenuated the possible impact of withdrawal on adrenal function. In agreement with most of the previous studies, our findings further suggest that, in recently withdrawn alcoholics, the HPA axis may be overdriven, and the feedback regulation disrupted in many of them. It is still unclear whether such changes may be related to alcohol withdrawal, a condition which introduces possible limitations in the study in that it may itself stimulate the HPA axis. Our patients underwent a short withdrawal programme, and did not show overt abstinence symptoms, but biochemical changes may still have occurred to explain the nearly absent HPA response to both CRH and insulin administration. Whether these neuroendocrine abnormalities in abstinent alcoholics represent biological markers of underlying genetic susceptibility to alcoholism or simply the result of several years of exposure to alcohol remains an unanswered question. For technical reasons, we were unable to follow up patients to re-evaluate their subsequent HPA function; further studies should be designed to also elucidate the contribution of persisting HPA abnormalities to the risk of relapse in these patients. Alternatively, HPA abnormalities may simply represent a nonspecific stress response which is common to several other conditions. In this study, alcoholics did not complain of depressive disturbances and showed preserved cognitive function, but it is well known that sustained alcohol consumption is frequently associated with depression or increased familiarity for depression and mental deterioration (Ross et al., 1988). It is of interest in this respect that conditions characterized by deranged HPA activity, such as depression and Cushing's disease, may be associated with various degrees of mental impairment, while degenerative dementia, in which HPA overactivity is frequently present, represents a paradigm of disrupted cognition in humans (Martignoni et al., 1992).

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Alterations of H P A functioning may thus reflect the existence of a c o m m o n biological substrate for conditions which apparently recognize a different aetiology, but have been encompassed in a spectrum of neurobehavioural disturbances (Winokur et al., 1970).

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