Circadian rhythms of cortisol during alcohol withdrawal

Drug-induced stress responses and addiction risk and relapse

A number of studies have assessed the effects of psychoactive drugs on stress biology, the neuroadaptations resulting from chronic drug use on stress biology, and their effects on addiction risk and relapse. This review mainly covers human research on the acute effects of different drugs of abuse (i.e., nicotine, cannabis, psychostimulants, alcohol, and opioids) on the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) responses. We review the literature on acute peripheral stress responses in naïve or light recreational users and binge/heavy or chronic drug users. We also discuss evidence of alterations in tonic levels, or tolerance, in the latter relative to the former and associated changes in the phasic stress responses. We discuss the impact of the stress system tolerance in heavy users on their response to drug- and stress-related cue responses and craving as compared to control subjects. A summary is provided of the effects of glucocorticoid responses and their adaptations on brain striatal and prefrontal cortices involved in the regulation of drug seeking and relapse risk. Finally, we summarize important considerations, including individual difference factors such as gender, co-occurring drug use, early trauma and adversity and drug use history and variation in methodologies, that may further influence the effects of these drugs on stress biology.

Different Subjective and Objective Responses to Alcohol Among Heavy and Light Drinkers of Han and Uyghur Nationalities in China

OBJECTIVE

Given the observed differences in alcohol consumption characteristics between the Han and Uyghur nationalities in clinical reports and in daily life, the subjective and objective responses to alcohol in heavy drinkers (HDs) and light drinkers (LDs) in the Han and Uyghur nationalities in China were compared.

METHODS

A within-subject, double-blind, placebo-controlled human laboratory paradigm was performed. Each subject completed three experimental sessions in random order. Biphasic Alcohol Effects Scale and Positive and Negative Affect Schedule scales were administered, and heart rate (HR), blood pressure, and salivary cortisol levels were measured at predrink baseline and 30, 60, 120, and 180 minutes after the initial alcohol beverage consumption.

RESULTS

Compared with LDs, HDs exhibited higher stimulation, positive affect, and lower sedation in both ethnicities. Han drinkers (both HDs and LDs) exhibited higher sedation and lower positive affect and stimulation than Uyghur drinkers after consumption of alcohol. Moreover, HDs exhibited more HR increase during the ascending limb of breath alcohol content (p < .05) and less cortisol level during the declining limb of breath alcohol content (p < .05). Both HDs and LDs exhibited decreased systolic and diastolic pressures for both high- and low-dose beverages (ps < .01).

CONCLUSION

Compared with LDs, HDs exhibited more HR increase and lower salivary cortisol level after alcohol consumption. Han drinkers (both HDs and LDs) exhibited higher sedation and lower positive affect and stimulation after consumption of alcohol as compared with Uyghur drinkers. This modality of subjective and physiological responses to alcohol in the Han and Uyghur ethnicities is similar.

HPA Axis Interactions with Behavioral Systems

Perhaps the most salient behaviors that individuals engage in involve the avoidance of aversive experiences and the pursuit of pleasurable experiences. Engagement in these behaviors is regulated to a significant extent by an individual's hormonal milieu. For example, glucocorticoid hormones are produced by the hypothalamic-pituitary-adrenocortical (HPA) axis, and influence most aspects of behavior. In turn, many behaviors can influence HPA axis activity. These bidirectional interactions not only coordinate an individual's physiological and behavioral states to each other, but can also tune them to environmental conditions thereby optimizing survival. The present review details the influence of the HPA axis on many types of behavior, including appetitively-motivated behaviors (e.g., food intake and drug use), aversively-motivated behaviors (e.g., anxiety-related and depressive-like) and cognitive behaviors (e.g., learning and memory). Conversely, the manuscript also describes how engaging in various behaviors influences HPA axis activity. Our current understanding of the neuronal and/or hormonal mechanisms that underlie these interactions is also summarized. © 2016 American Physiological Society. Compr Physiol 6:1897-1934, 2016.

Mifepristone pretreatment reduces ethanol withdrawal severity in vivo

BACKGROUND

Prolonged ethanol (EtOH) intake may perturb function of the hypothalamic-pituitary-adrenal axis in a manner that promotes dependence and influences EtOH withdrawal severity. Prior in vivo and in vitro studies suggest that corticosteroids, in particular, may be elevated during EtOH intoxication and withdrawal, suggesting that intracellular glucocorticoid receptors (GRs) may promote the development of EtOH dependence.

METHODS

Adult male Sprague-Dawley rats were subjected to a 4-day binge-like EtOH administration regimen (3 to 5 g/kg/i.g. every 8 hours designed to produce peak blood EtOH levels (BELs) of <300 mg/dl). Subgroups of animals received s.c. injection of the GR antagonist mifepristone (20 or 40 mg/kg in peanut oil at 0800 hours on each of the 4 days prior to withdrawal). BELs were assessed at 0900 and 1500 hours on Days 2 (D2) and 4 (D4) of the regimen. BEL, blood corticosterone levels (BCLs), and EtOH withdrawal-associated behavioral abnormalities were assessed 10 to 12 hours after the final EtOH administration.

RESULTS

Daily mean EtOH doses for D1 to D4 of the regimen were 14.4, 9.9, 7.1, and 8.6 g/kg, respectively. The EtOH gavage regimen produced mean BELs of 255 mg/dl at 0900 on D2 and 156.2 mg/dl at 0900 on D4 of the regimen. Withdrawal from the EtOH exposure regimen, beginning 10 hours after the last EtOH administration, produced significant elevations in BCL and behavioral abnormalities including tremors, stereotypy, and "wet dog shakes." Mifepristone administration did not alter food intake or weight during the 4-day regimen, nor were there drug-dependent differences in BEL or BCL on withdrawal day. Although mifepristone produced no significant changes in behavior of EtOH-naïve animals, pretreatment with mifepristone (40 mg/kg) significantly reduced the severity of EtOH withdrawal.

CONCLUSIONS

Findings suggest that activation of GRs promotes neuroadaptation to binge-like EtOH exposure, contributing to the development of EtOH dependence. Further, GRs may represent therapeutic targets to be exploited in reducing the severity of EtOH withdrawal.

Social rank, chronic ethanol self-administration, and diurnal pituitary-adrenal activity in cynomolgus monkeys

RATIONALE

Dominance hierarchies affect ethanol self-administration, with greater intake among subordinate animals compared to dominant animals. Excessive ethanol intake disrupts circadian rhythms. Diurnal rhythms of the hypothalamic-pituitary-adrenal axis have not been characterized in the context of ethanol self-administration with regard to social rank.

OBJECTIVE

This study aimed to determine whether diurnal pituitary-adrenal hormonal rhythms account for differences between social ranks in ethanol self-administration or are differentially affected by ethanol self-administration between social ranks.

METHODS

During alternating individual (n = 11-12) and social (n = 3 groups) housing of male cynomolgus monkeys (Macaca fascicularis), diurnal measures of cortisol and adrenocorticotropic hormone (ACTH) were obtained from plasma samples three times per week. Social rank was determined, ethanol (4 %, w/v) self-administration was induced, and then the monkeys were allowed a choice of water or ethanol for 22 h/day for 49 weeks.

RESULTS

For all social ranks, plasma ACTH was elevated during social housing, but cortisol was stable, although greater among dominant monkeys. Ethanol self-administration blunted the effect of social housing, cortisol, and the diurnal rhythm for both hormones, regardless of daily ethanol intake (1.2-4.2 g/kg/day). Peak ACTH and cortisol were more likely to be observed in the morning during ethanol access. Ethanol, not vehicle, intake was lower during social housing across social ranks. Only dominant monkeys showed significantly lower blood-ethanol concentration during social housing.

CONCLUSIONS

There was a low threshold for disruption of diurnal pituitary rhythms by ethanol drinking, but sustained adrenal corticosteroid rhythms. Protection against heavy drinking among dominant monkeys may have constrained ethanol intoxication, possibly to preserve dominance rank.

Endocrine alterations during a detoxification treatment with carbamazepine in male alcoholics

This study aimed to evaluate the prevalence and time-course of endocrine alterations in male alcohol addicts during a detoxification treatment and to examine a possible relation between endocrine alterations and depressive symptoms and overall mental distress. Blood samples were drawn in 54 male alcohol addicts on admission, at day 7 of treatment and at day 14 on discharge. Endocrine analysis was performed for cortisol, luteinizing hormone, prolactin, androgens, free testosterone and 17beta-estradiol. Psychometric measures (Beck's depression inventory and the symptom checklist-90-R) were taken on admission and on discharge and were correlated with endocrine measures. Cortisol plasma levels were substantially increased at the beginning of the detoxification, whereas all other endocrine parameters were within the normal range. Although subjects depicted mild to moderate levels of depressive symptoms and mental distress, there were no correlations with endocrine variables. Further analysis revealed a high variation in sex steroid levels with approximately 55% of participants showing initial (n = 19) or developing (n = 11) hypogonadal values during detoxification. In conclusion, chronic alcohol consumption induces disturbances of gonadal function which are reversible in the majority of cases. However, few patients develop a hypogonadal state during detoxification. Initially increased cortisol levels indicate a bodily stress response with the onset of alcohol withdrawal but are not related to mental disturbances.

Attenuated cortisol response to alcohol in heavy social drinkers

Individual differences in response to stress may play a role in the development and maintenance of addictive behaviors. While there is evidence that people with a biological family history for alcoholism have a blunted cortisol response to alcohol, data are lacking in other at-risk subgroups, such as heavy social drinkers. The present study examined salivary cortisol response to administration of 0.0, 0.4 (2 drink equivalent), and 0.8 g/kg (4 drink equivalent) alcohol in two groups of social drinkers: heavy drinkers (n=32) and light social drinkers (n=23). The study was conducted double-blind and drink-order was counterbalanced between groups. Salivary cortisol and subjective measures were obtained at predrink baseline, and 15, 45, 105, and 165 min after beverage consumption. Results showed a significant groupxdosextime interaction (p<0.005), with alcohol (0.8 g/kg) producing an attenuated cortisol response in heavy drinkers compared to the light drinkers during the declining phase of the BAC. This outcome remained even after controlling for the effects of smoking status, family history of alcoholism, sex, and negative affect ratings during the session. Neither placebo nor the lower dose of alcohol significantly increased cortisol levels. In sum, a relatively high dose of alcohol produced a smaller increase in cortisol in heavy drinkers compared to light drinkers. The reduced cortisol reactivity in the heavier drinkers is consistent with reports that individuals at risk for alcoholism are hyporesponsive to physical and psychological stress. Further research may help determine whether alteration in cortisol response to alcohol is a biological marker of the propensity to abuse alcohol.

Corticosterone Increases Damage and Cytosolic Calcium Accumulation Associated With Ethanol Withdrawal in Rat Hippocampal Slice Cultures

BACKGROUND

Evidence suggests that stress hormones (i.e., glucocorticoids) may be increased during acute or chronic consumption of ethanol and during withdrawal from ethanol consumption, effects that may contribute to the development of cognitive impairment. The goal of the current studies was to examine the hypothesis that increased glucocorticoid levels in conjunction with ethanol exposure and withdrawal may cause hippocampal damage.

METHODS

Organotypic hippocampal slice cultures were exposed to 50 mM ethanol for 10 days and withdrawn for 1 day. After withdrawal, cytotoxicity and cytosolic Ca2+ accumulation were measured using the nucleic acid stain propidium iodide and Calcium Orange, AM, respectively. Cultures were also treated with nontoxic concentrations of corticosterone (0.001-1 microM) during ethanol exposure and withdrawal or only during withdrawal. Additional cultures were coexposed to corticosterone and RU486 (0.1-10.0 microM), spironolactone (0.1-10.0 microM), or MK-801 (20 microM) during ethanol exposure and/or withdrawal.

RESULTS

Ethanol withdrawal did not increase propidium iodide fluorescence and cytosolic Ca2+ levels. However, significant increases in propidium iodide fluorescence and in cytosolic Ca2+ accumulation were observed in cultures when corticosterone (> or = 100 nM) was exposed during ethanol treatment and/or withdrawal. These effects of corticosterone on ethanol withdrawal were attenuated by RU486 and MK-801 but not by spironolactone coexposure.

CONCLUSIONS

This report demonstrated that corticosterone exposure during ethanol treatment and/or withdrawal resulted in significant hippocampal damage, possibly via activation of glucocorticoid receptors and enhancement of the glutamatergic cascade. The findings from these studies suggest that glucocorticoids contribute to the neuropathological consequences of alcohol dependence in humans.

Early Experience and Sex Interact to Influence Limbic-Hypothalamic-Pituitary-Adrenal-Axis Function After Acute Alcohol Administration in Rhesus Macaques (Macaca mulatta)

BACKGROUND

Studies in rodents demonstrate sex differences in neuroendocrine stress axis activity after treatment with alcohol. In abstinent alcoholics, atypical depressives, and individuals with posttraumatic stress disorder, limbic-hypothalamic-pituitary-adrenal (LHPA)-axis activity is often blunted; among females in these patient populations, however, resistance to glucocorticoid feedback and increased pituitary reactivity is observed. Early parental loss is a major life stressor and is a risk factor for both affective disturbances and LHPA-axis abnormalities later in life. We wanted to determine whether sex and early life parental absence would interact to influence alcohol-induced alterations in LHPA-axis activity after exposure to ethanol in macaques.

METHODS

Animals were reared with their mothers in social groups (MR, n = 94) or without adults in peer-only groups (PR, n = 79). At 5 years of age, they received an intravenous infusion of alcohol (2-2.2 g/kg), and the effects of alcohol, sex, and rearing condition on ACTH and cortisol levels were analyzed by ANOVA.

RESULTS

Peer-reared females had higher ACTH levels than did PR males, MR females, and MR males after alcohol infusion. Alcohol-induced cortisol levels were not affected by sex and rearing condition.

CONCLUSIONS

These findings suggest that there are sex differences in glucocorticoid negative feedback, pituitary responsivity, or release of ACTH secretagogues among individuals exposed to early life stress and emphasize the importance of considering sex effects when studying LHPA-axis dysregulation in alcoholism and other stress-related neuropsychiatric disorders.

Abnormal nocturnal melatonin secretion and disordered sleep in abstinent alcoholics

BACKGROUND

Alcoholic patients show prominent disturbance of sleep as measured by electroencephalogram, with difficulties in the onset and maintenance of sleep. Given the role of melatonin in the regulation of the sleep-wake cycle, this study examined the relationship between nocturnal expression of melatonin and sleep in alcoholics as compared with control subjects.

METHODS

Alcoholic patients (n = 11) and comparison control subjects (n = 10) underwent all-night polysomnography and serial blood sampling every 30 min from 10:00 PM to 6:30 AM for measurement of circulating levels of melatonin and cortisol.

RESULTS

Coupled with prolonged sleep latency, alcoholics showed lower levels of melatonin during the early part of the night and a delay in the onset of the nocturnal plateau or peak value of melatonin as compared with control subjects. The nocturnal delay of melatonin correlated with prolonged sleep latency. Circulating levels of cortisol were lower during the early part of the night and higher in the late part of night in the alcoholics as compared with the control subjects.

CONCLUSIONS

A delay in the nocturnal rise of melatonin may contribute to disordered sleep in chronic alcoholics, with implications for the use of melatonin in the treatment of insomnia in recovering alcoholics.

Role of PGE2 in the development of pancreatic injury induced by chronic alcohol feeding in rats

BACKGROUND

Eicosanoids are known to modulate inflammation. Moreover, some studies report that endogenous prostaglandin E(2) (PGE(2)) protects the pancreas against injury. Therefore, we investigated its role in a rat model of chronic alcohol consumption.

METHODS

Rats were fed with 20% ethanol and a corn oil-supplemented diet using the interrupted alcohol feeding regimen (EI). Controls received water instead of ethanol (WI) or uninterruptedly ethanol (EU). After 13 mo, pancreas tissue was investigated morphologically, immunohistochemically and biochemically.

RESULTS

Pancreatic tissue was more severely injured in EI than in WI and EU (p < 0.05). Fibrogenesis (alpha-smooth muscle actin-positive cells, collagen types I and III) was increased in EI compared to WI (p < 0.05). In EI, mast cell numbers were increased, compared to WI, but decreased, compared to EU (p < 0.05). EI showed decreased PGE(2) and malondialdehyde contents compared to EU (p < 0.05) and decreased glutathione concentrations compared to WI (p < 0.05). PGE(2) content and fibrogenesis were inversely correlated in EU. The same correlation was detectable as a trend in all alcohol-fed rats.

CONCLUSION

The decrease in PGE(2) together with the increase in tissue damage and the inverse correlation between PGE(2) and fibrogenesis led us to suggest that endogenous PGE(2) plays a protective role in alcohol-induced injury in the pancreas.

Alcohol and withdrawal: from animal research to clinical issues

The withdrawal syndrome in alcohol-dependent patients appears to be a major stressful event whose intensity increases with repetition of detoxifications according to a kindling process. Disturbances in the balance between excitatory and inhibitory neural processes are reflected in a perturbed physical state while disturbances in the balance between positive and negative reinforcements are reflected in a perturbed mood state. Our purpose is to link the different behavioral outcomes occurring during withdrawal with specific biological brain mechanisms from the animal to the human being. Better understanding of the various biological mechanisms underlying withdrawal from alcohol will be the key to design and to apply appropriate pharmaceutical management, together with appropriate therapy aimed at inducing protracted abstinence.

Modulation of cellular expression of glucocorticoid receptor and glucocorticoid response element-DNA binding in rat brain during alcohol drinking and withdrawal

To define the molecular mechanisms of abnormal hypothalamic pituitary adrenal (HPA) axis during ethanol dependence, we investigated the effect of chronic ethanol treatment (15 days) and its withdrawal (24 h) on the expression of glucocorticoid receptors (GRs) and glucocorticoid response element (GRE)-DNA binding in the rat brain. The effects of chronic mianserin [serotonin (5-HT)(2A/2C) antagonist] treatment on these parameters in various brain structures of control diet-fed and ethanol-fed rats were also investigated. It was found that ethanol treatment and withdrawal significantly decreased the GR protein levels in cortical (cingulate gyrus, frontal, parietal, and piriform cortex) and amygdaloid (central, medial, and basolateral) structures and paraventricular nucleus (PVN) of hypothalamus of rats. It was also observed that ethanol treatment produced significant reductions in GR protein levels in various hippocampal structures (CA1, CA2, CA3, and dentate gyrus), but these changes were normalized during ethanol withdrawal. Ethanol treatment also significantly decreased GRE-DNA binding in rat cortex and hippocampus, which remained decreased in the cortex but reverted to normal in hippocampus during ethanol withdrawal. Chronic mianserin (alone) treatment had no effect on cortical GRE-DNA binding and GR protein levels in cortical, amygdaloid, or PVN structures but significantly decreased the GR protein expression in various hippocampal structures and GRE-DNA binding in whole hippocampus. However, when administered concurrently with ethanol treatment, mianserin significantly antagonized the reductions in cortical GRE-DNA binding and in GR protein expression in cortical, PVN, and central, but not medial and basolateral, amygdaloid structures during ethanol withdrawal. On the other hand, mianserin treatment along with ethanol administration significantly decreased the hippocampal GRE-DNA binding and GR protein expression in various hippocampal structures during ethanol withdrawal. Furthermore, ethanol treatment and its withdrawal or mianserin treatment had no effect on the neuron-specific nuclear protein levels in the various brain structures. Taken together, these results indicate that interaction of 5-HT(2A/2C) receptors with GRs in cortical, central amygdaloid, and PVN structures may play a role in neural mechanisms of alcohol dependence. It is possible that decreased GR expression in PVN may be responsible for the abnormal HPA axis during ethanol exposure and withdrawal.

Circadian rhythms of hormone concentrations in alcohol withdrawal

We investigated the circadian rhythm of hormones (cortisol, melatonin) in alcoholic patients during and 1 month after alcohol withdrawal. Patients with delirium tremens had irregular serum hormone concentration rhythms during withdrawal, which normalized after the withdrawal period. Patients without delirium tremens had normal circadian rhythms even during the withdrawal period. We speculated that the disturbance of the biological oscillator, in terms of the decline of synchronizing function or the decrease in synchronizing factors, caused abnormal circadian rhythms of hormone release during delirium tremens.

Endocrine effects of nicotine administration, tobacco and other drug withdrawal in humans

The focus of this manuscript is on the effects of smoking and tobacco withdrawal on the hypothalamic-pituitary axis (HPA). A variety of studies have shown that nicotine administered intravenously or through intense cigarette smoking can induce changes in hormones associated with the HPA. Administration of, and abrupt cessation from, other drugs of abuse has also been shown to affect levels of these hormones. Additionally, many of the symptoms of stress and tobacco withdrawal overlap suggesting that the hormonal changes seen during periods of stress may be observed during tobacco abstinence. These findings led to a study of the effects of tobacco withdrawal on plasma ACTH, cortisol, and prolactin levels. The results indicated tobacco cessation caused small and transient effects on plasma hormone levels which were not significantly influenced by nicotine replacement and were not related to other signs of withdrawal.

Zinc deficiency and corticosteroids in the pathogenesis of alcoholic brain dysfunction--a review

Chronic alcoholism is associated with hypercortisolemia and low serum zinc (Zn). Hypercortisolemia could be responsible for alcoholic cerebral atrophy and is also associated with enhanced NMDA neurotoxicity. It is hypothesized that low brain Zn, noted in chronic alcoholics, enhances NMDA excitotoxicity and ethanol withdrawal seizure susceptibility. Also, Zn deficiency can produce neuronal damage through increased free radical formation. Clinically, Zn replacement therapy may be a rational approach to the treatment of alcohol withdrawal seizures and alcohol-related brain dysfunction.

Effects of acute and repeated alcohol ingestion on hypothalamic-pituitary-gonadal and hypothalamic-pituitary-adrenal functioning in normal males

We investigated the effects of acute and repeated alcohol ingestion on plasma levels of hormones associated with the functioning of the hypothalamic-pituitary-gonadal (HPG) and hypothalamic-pituitary-adrenal (HPA) systems in normal males. In the first experiment, 7 normal male subjects were given ethanol (1.3 g/kg) in the form of a 43% alcohol solution of whiskey and water over a 30-min period (from 19:00 h to 19:30 h); blood samples were collected 30 min and immediately before the beginning of alcohol ingestion and then at intervals of 30 min for 180 min. Blood ethanol levels rose sharply and reached their maximum at 60 min, remaining above 1.0 mg/ml until 180 min. Prolactin levels increased, reaching a peak at 60 min, gradually returning to the initial value at 180 min. Decreased testosterone levels were observed only at 30 min. Luteinizing hormone (LH), adrenocorticotrophic hormone (ACTH) and cortisol levels did not show any increases. In the second experiment, 9 normal males were given the same dose of alcohol, but this was given on 7 consecutive evenings and the hormonal changes were examined on the 1st and 7th days, only at 30 and 60 min after alcohol ingestion began (during the period that blood ethanol levels were ascending to their peak). The results on the 1st day reconfirmed the findings in the first experiment and on the 7th day, the last alcohol ingestion produced increases in prolactin levels and decreases in testosterone levels at 30 and 60 min, but did not change other hormone levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypothalamic-pituitary function during alcohol exposure and withdrawal and cocaine exposure

This chapter examines the neuroendocrine effects of acute exposure to and withdrawal from alcohol and cocaine, with special emphasis on the hypothalamic-pituitary-adrenal (HPA) axis. We present the results from two preliminary controlled inpatient studies that document HPA dysfunction during acute exposure to alcohol and cocaine and during withdrawal from alcohol. We discuss the methodological approach of these studies in comparison to related attempts in the literature to use measures of thyroid and prolactin regulation to predict risk of relapse to alcohol and cocaine use, respectively. Our data and the results of related studies are presented in the context of a proposed index of HPA axis dysfunction that may provide a useful clinical measure of susceptibility to relapse during protracted abstinence from alcohol or cocaine.

Pharmacotherapies for alcoholism: promising agents and clinical issues

The past 10 years have witnessed important advances in research on pharmacotherapy for alcoholism. Promising drugs are discussed under six headings: agents to treat alcohol withdrawal; anticraving agents; agents that make drinking an aversive experience; agents to alleviate concomitant psychiatric problems; agents to treat concurrent drug abuse; and amethystic ("sobering-up") agents. Research on the drug classes is summarized and clinical issues surrounding specific agents and alcoholism pharmacotherapy in general are discussed. Finally, long-range therapeutic implications of recent findings on the actions of alcohol on basic mechanisms of the brain are offered.

Overexcitement and disinhibition. Dynamic neurotransmitter interactions in alcohol withdrawal

In alcohol withdrawal, abnormalities occur in a number of neurotransmitter systems: there is reduced inhibitory function, and increased activity of excitatory systems. The former, indicated by reduced GABA and alpha-2-adrenoceptor activity, acts in conjunction with, and is exacerbated by, the latter, which itself may be due to the potentiation of NMDA activity by depletion of magnesium, and overactivity of catecholaminergic and CRF neurones. These dysfunctions produce immediate effects and may also contribute to the long-term changes in brain excitability by a kindling-like process. It is possible that early and active treatment may oppose this process. Present strategies for treatment of alcohol withdrawal enhance GABA and alpha-2 inhibitory, or reduce excitatory, mechanisms. Future possibilities include the use of CRF and/or NMDA antagonists.

Alcoholism and panic disorder: is the comorbidity more than coincidence?

Studies on alcoholic patients have found a higher than expected prevalence of panic disorder, and suggest a positive correlation between the level of alcohol consumption and severity of anxiety. Conversely, there is an increased prevalence of alcoholism among patients with panic disorder and their blood relatives. A comparison of symptoms, physiological and neurochemical changes known to occur in both alcohol withdrawal and panic disorder reveals a degree of similarity between the 2 conditions. Based on the data, we propose that the chemical and cognitive changes occurring as the result of repeated alcohol withdrawals may kindle and condition coincidence of panic attacks in susceptible individuals. Implications of our postulates for treatment of alcohol withdrawal and panic disorder in alcoholics and for future studies are discussed.

Neuropharmacological and clinical aspects of alcohol withdrawal

Abnormalities in the function or activity of several neurotransmitter systems have been demonstrated after acute and chronic, exposure to alcohol, and in alcohol withdrawal. The changes can be divided into alterations in function of inhibitory and excitatory systems. Inhibitory dysfunction is indicated by reduced gamma-aminobutyric acid and alpha-2-adrenoceptor activity. In conjunction with, and exacerbating this, is increased activity of excitatory systems, perhaps the most significant of which is the probable potentiation of N-methyl-D-aspartate activity by depletion of magnesium. There is additional, and possibly secondary, overactivity of catecholamine and corticotropin releasing factor neuronal systems. Other, less specific changes include increased numbers of calcium channels, which would increase neuronal excitability. The evidence for these changes is presented, and the implications for new treatment regimes for alcohol withdrawal are discussed.