A cerebrospinal fluid study of the pathophysiology of panic disorder associated with alcoholism

Peripheral Biomarkers in DSM-5 Anxiety Disorders: An Updated Overview

Anxiety disorders are prevalent and highly disabling mental disorders. In recent years, intensive efforts focused on the search for potential neuroimaging, genetic, and peripheral biomarkers in order to better understand the pathophysiology of these disorders, support their diagnosis, and characterize the treatment response. Of note, peripheral blood biomarkers, as surrogates for the central nervous system, represent a promising instrument to characterize psychiatric disorders, although their role has not been extensively applied to clinical practice. In this report, the state of the art on peripheral biomarkers of DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th edition) Anxiety Disorders is presented, in order to examine their role in the pathogenesis of these conditions and their potential application for diagnosis and treatment. Available data on the cerebrospinal fluid and blood-based biomarkers related to neurotransmitters, neuropeptides, the hypothalamic-pituitary-adrenal axis, neurotrophic factors, and the inflammation and immune system are reviewed. Despite the wide scientific literature and the promising results in the field, only a few of the proposed peripheral biomarkers have been defined as a specific diagnostic instrument or have been identified as a guide in the treatment response to DSM-5 Anxiety Disorders. Therefore, further investigations are needed to provide new biological insights into the pathogenesis of anxiety disorders, to help in their diagnosis, and to tailor a treatment.

Epidemiology of panic attacks, panic disorder and the moderating role of age: Results from a population-based study

BACKGROUND

The aim of this study was to investigate the prevalence of panic attacks (PA) and panic disorder (PD) over the lifespan, determine the main correlates and analyze the potential moderating role of age.

METHOD

We analyzed cross-sectional data from a nationally-representative sample of 4,569 non-institutionalized adults. Three panic groups were created according to results in the CIDI interview: non-panic, PA (without PD) and PD. Panic groups were used as outcomes in adjusted multinomial regression models where several correlates were investigated. Interactions between each covariate and age were explored.

RESULTS

The highest prevalence rates of PA (9.5%) and PD (3.3%) were found in people aged 30-39 and 40-49, respectively. Respondents aged 80 + presented the lowest rates. In the adjusted multinomial model, younger ages, having depression, and poorer levels of quality of life were significant correlates for both PA and PD, whereas being female and having 2 or more chronic conditions were only significant for PA (not for PD) and being a frequent drinker (last 12-months) only for PD. Age significantly interacted with frequent alcohol consumption in the last 12-months for PD. The predicted probability of having PD decreased with age for life-abstainer or occasional drinkers, whereas the probability increased with older ages for frequent drinkers.

LIMITATIONS

Low prevalence of PA and PD resulted in large confidence intervals whereas self-reports could be affected by recall bias.

CONCLUSIONS

Overall, our results suggest that the probability of having PA and PD decreases as people age and that the significant risk factors are independent of age. However, older adults with a frequent drink pattern seem to be at higher risk of PD. Future longitudinal studies are needed to determine the trajectories of PD and alcohol consumption over the lifespan.

Opioids and anxiety

The opioid system plays a crucial role in the neural modulation of anxiety. The involvement of opioid ligands and receptors in physiological and dysfunctional forms of anxiety is supported by findings from a wide range of preclinical and clinical studies, including clinical trials, experimental research, and neuroimaging, genetic, and epidemiological data. In this review we provide a summary of studies from a variety of research disciplines to elucidate the role of the opioid system in the neurobiology of anxiety. First, we report data from preclinical studies using animal models to examine the modulatory role of central opioid system on defensive responses conducive to fear and anxiety. Second, we summarize the human literature providing evidence that clinical and experimental human studies are consistent with preclinical models. The implication of these data is that activation of the opioid system leads to anxiolytic responses both in healthy subjects and in patients suffering from anxiety disorders. The role of opioids in suppressing anxiety may serve as an adaptive mechanism, collocated in the general framework of opioid neurotransmission blunting acute negative and distressing affective responses.

The role of central noradrenergic dysregulation in anxiety disorders: evidence from clinical studies

The nature of the noradrenergic dysregulation in clinical anxiety disorders remains unclear. In panic disorder, the predominant view has been that central noradrenergic neuronal networks and/or the sympathetic nervous system was normal in patients at rest, but hyper-reactive to specific stimuli, for example carbon dioxide. These ideas have been extended to other anxiety disorders, which share with panic disorder characteristic subjective anxiety and physiological symptoms of excess sympathetic activity. For example, Generalized Anxiety Disorder is characterized by chronic free-floating anxiety, muscle tension, palpitation and insomnia. It has been proposed that there is chronic central hypersecretion of noradrenaline in Generalized Anxiety Disorder, with consequent hyporesponsiveness of central post-synaptic receptors. With regards to other disorders, it has been suggested that there is noradrenergic involvement or derangement, but a more specific hypothesis has not been enunciated. This paper reviews the evidence for noradrenergic dysfunction in anxiety disorders, derived from indirect measures of noradrenergic function in clinical populations.

Alcoholism in 274 patients with panic disorder in Spain, one of the main producers of wine worldwide

BACKGROUND

Though panic disorder (PD) and alcoholism have been found in epidemiologic studies to often co-occur, the influence of cultural factors on the order of onset of the disorders has not been frequently addressed.

METHODS

A sample of 274 patients with PD was assessed and compared according to the presence of alcohol use disorder (AUD) (alcohol abuse or dependence), employing several clinical scales.

RESULTS

A total of 26 subjects were diagnosed from AUD. In 73.1% of patients, onset of alcohol use was previous to PD onset. PD subjects with AUD were found to have an earlier age at PD onset. They were more likely to be males, to have a family history of alcoholism, to abuse other drugs and to experience a more severe PD (more attacks in the last month, higher scores in anticipatory anxiety).

CONCLUSIONS

Patients with PD and alcoholism may represent a distinct clinical subgroup. Our finding of an uncommon order of onset for both disorders may reflect cultural influences.

CLINICAL IMPLICATIONS

(i)The study of panic disorder patients with comorbid alcoholism may help to better characterize this subgroup of patients. (ii) Patterns of alcohol use and the order of onset of both disorders may be influenced by cultural factors, with important practical implications. (iii) Patients with panic disorder and alcoholism may represent a distinct clinical subgroup, with an earlier age at panic disorder onset and greater clinical severity of anxiety.

LIMITATIONS

(i) Our results refer to a clinical sample, which may not be representative of the general population. (ii) Alcoholic patients with a history of other drug abuse or dependence were not excluded. (iii) Owing to the small sample size, patients with alcohol dependence and with alcohol abuse were not separated.

The psychobiology of anxiolytic drugs. Part 1: Basic neurobiology

The authors provide an overview of the current state of knowledge with regards to the neurobiological mechanisms involved in normal and pathological anxiety. A brief review of the classification and cognitive psychology of anxiety is followed by a more in-depth look at the neuroanatomical and neurochemical processes and their relevance to our understanding of the modes of action of anxiolytic drugs. The serotonergic, noradrenergic, and gamma-aminobutyric acidergic systems are reviewed. The numerous physiological and pharmacological methods of anxiety provocation and the increasing importance of functional neuroimaging are also examined. The review provides an overview of the biology and basic pharmacology of anxiolytic drugs, and compliments the more clinically oriented companion review.

Severity of depression in abstinent alcoholics is associated with monoamine metabolites and dehydroepiandrosterone-sulfate concentrations

Depressed mood increases the relapse risk of abstinent alcoholics; its neurobiological correlates may include reduced serotonin and norepinephrine turnover rates and increased cortisol concentrations during detoxification stress. Neurosteroids such as dehydroepiandrosterone and its sulfate (DHEA and DHEA-S) may antagonize cortisol action and may have mood-elevating effects on their own. We measured severity of depression with Beck's Depression Inventory (BDI) and Hamilton's Depression Rating Scale (HDRS), plasma concentrations of cortisol, DHEA and DHEA-S, and CSF concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA), the norepinephrine metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) and the dopamine metabolite homovanillic acid (HVA) in 21 abstinent alcoholics after 4 weeks of abstinence and in 11 age-matched healthy control subjects. Only CSF MHPG concentrations were reduced in alcoholics compared to control subjects (41.4 +/- 6.6 vs. 53.3 +/- 8.6 pmol/ml). Self-rated depression was significantly correlated with CSF MHPG (Spearman's R = +0.57, P < 0.01), CSF 5-HIAA (R = +0.51, P < 0.05) and plasma cortisol concentrations (R = +0.50, P < 0.05). Negative correlations were found between DHEA-S concentrations and both self-rated depression (R = -0.45, P < 0.05) and observer-rated depression (R = -0.55, P < 0.05). The ratio of DHEA-S to cortisol serum concentrations was also negatively correlated with depression (BDI: R = -0.55, P < 0.01; HDRS: R = -0.63, P < 0.005). Anxiety (Spielberger's State Anxiety Scale) was only associated with CSF MHPG concentrations (R = +0.58, P < 0.01). Our findings point to the importance of noradrenergic dysfunction in the pathogenesis of depression among abstinent alcoholics and indicate that their mood states may also be modulated by a low DHEA-S to cortisol ratio, hypothetically indicative of low stress protection capacities.

Neurochemical correlates of sympathetic activation during severe alcohol withdrawal

Cerebrospinal fluid (CSF) was obtained from 17 patients during acute alcohol withdrawal. Eight of these 17 patients had a second lumbar puncture a mean of 11.9 +/- 8.1 (SD) days later, when the clinical signs of alcohol withdrawal had subsided. CSF 3-methoxy-4-hydroxyphenylglycol concentrations declined significantly (p < 0.05) during the course of alcohol withdrawal from 52.0 +/- 22.1 (SD) to 39.6 +/- 12.6 pM/ml. In early withdrawal, there was a significant positive correlation between CSF norepinephrine (NE) and corticotropin releasing hormone (CRH) concentrations (r = 0.95, p < 0.001). Both NE and CRH concentrations correlated positively with diastolic blood pressure (r = 0.88, p < 0.001 and r = 0.62, p < 0.05, respectively). In all samples, CSF 5-hydroxyindole acetic acid concentrations correlated positively with CSF-homovanillic acid concentrations (r = 0.83, p < 0.001). These findings indicate significant perturbations of the noradrenergic neuronal system and a change in CRH-NE interactions during acute alcohol withdrawal.

Alcohol and depression in panic disorder

Panic disorder (PD) is a common psychiatric illness, which has many complications such as major depression, increased suicide risk, agoraphobic avoidance behaviour, alcohol abuse and dependence. A number of studies have now documented increased rates of anxiety disorders among alcoholics and of alcoholism among patients presenting with anxiety disorders. In general, it appears that PD is more prevalent in alcoholics than would be expected on the basis of general population rates. Alcohol withdrawal is clearly associated with severe anxiety symptoms. It is suggested that repeated withdrawal episodes may trigger panic through a kindling process by causing subconvulsive stimuli with increasing amounts of electrical excitability or even spontaneous seizures. Serotonergic medications are effective in treating PD and depression. They also diminish interest in drinking in ethanol-dependent patients. Serotonergic agents can also affect conditioning and learning as well as behavioral control and self-administration. The treatment of panic patients with depressive and alcohol problems usually requires long-term treatment.

CSF diazepam-binding inhibitor concentrations in panic disorder

Diazepam-binding inhibitor (DBI) is a neuropeptide that has been detected in the brain and cerebrospinal fluid (CSF). Previous studies have suggested the possible role of DBI as a potential endogenous anxiogenic ligand modulating GABAergic transmission at the benzodiazepine-GABA receptor complex. The measurement of DBI immunoreactivity (DBI-IR) in CSF of panic-disorder patients and normal controls was undertaken to assess whether there were differences in the CSF concentration of this peptide to assess possible relationships with other monoamines and peptides. Lumbar CSF was obtained from 18 panic patients (4 men, 14 women) and 9 controls (5 men, 4 women). As a group, no significant differences were found between panic patients' CSF concentration of DBI-IR (1.12 +/- 0.27 pmol/mL) and normal volunteers (1.23 +/- 0.27 pmol/mL). No gender differences were demonstrated. However, we did find a positive correlation between CSF levels of DBI and CSF corticotropin releasing hormone (CRH) in our panic patients.

Panic attacks. A neurochemical overview of models and mechanisms

The delineation of panic disorder as a distinct diagnostic entity has provided renewed impetus for research into panic. This review describes and examines the range of neurobiological theories of panic attacks. It illustrates the diversity of mechanisms that have been invoked to explain the production of panic attacks, and which have influenced much of the current thinking about the neurochemistry of anxiety.

Alcohol abuse, substance abuse, and panic disorder

The purpose of this article is to review the literature concerning the interaction of alcohol and/or substance abuse with panic disorder, the comorbidity of these disorders, possible causal relationships, biologic relationships, and the recognition and treatment of dually disordered patients. A number of studies suggest significant comorbidity between panic disorder and alcoholism or abuse of drugs, especially cocaine and sedatives. Panic may lead to drinking or sedative use and also result from prolonged use or withdrawal of alcohol or other drugs. Possible biologic relationships involve the gamma-aminobutyric acid (GABA)-benzodiazepine receptor complex and the central noradrenergic system. Although treatment of panic in substance abusers has not been studied specifically, guidelines for recognition and management of these patients, including use of antipanic medication, are discussed.