THE PSYCHOPHYSIOLOGY OF ANXIETY; WITH A REVIEW OF THE LITERATURE CONCERNING ADRENALINE

Can scent-detection dogs detect the stress associated with trauma cue exposure in people with trauma histories? A proof-of-concept study

Introduction

Post-traumatic stress disorder (PTSD) is an impairing mental health condition with high prevalence among military and general populations alike. PTSD service dogs are a complementary and alternative intervention needing scientific validation. We investigated whether dogs can detect putative stress-related volatile organic compounds (VOCs) in the breath of people with trauma histories (54% with PTSD) exposed to personalized trauma cues.

Methods

Breath samples were collected from 26 humans over 40 experimental sessions during a calm (control breath sample) and stressed state induced by trauma cue exposure (target breath sample). Two scent detection canines were presented with the samples in a two alternative forced choice (2AFC) discrimination and yes/no detection task. The 2AFC task assessed the dogs' ability to discriminate between the two states within the breath samples of one individual. The detection task determined their ability to generalize the target odour across different individuals and different stressful events of one individual. Signal Detection Theory was applied to assess dogs' sensitivity, specificity, precision, and response bias.

Results

The dogs performed at ∼90% accuracy across all sample sets in the discrimination experiment, and at 74% and 81% accuracy, respectively, in the detection experiment. Further analysis of dog olfactory performance in relation to human donor self-reported emotional responses to trauma cue exposure suggested the dogs may have been detecting distinct endocrine stress markers. One dog's performance correlated with the human donors' self-reported fear responses and the other dog's performance correlated with the human donors' self-reported shame responses. Based on these correlations between dog performance and donor self-report measures, we speculate that the VOCs each dog was detecting likely originated from the sympathetico-adreno-medullary axis (SAM; adrenaline, noradrenaline) in the case of the first dog and the hypothalamo-pituitary-adrenal axis (HPA; glucocorticoids) in the case of the second dog.

Conclusion

Our proof-of-concept study is the first to demonstrate that some dogs can detect putative VOCs emitted by people with trauma histories when experiencing distress theoretically associated with the intrusion and arousal/reactivity symptoms of PTSD. Results have potential to improve the effectiveness and training protocol of PTSD service dogs with a focus on enhancing their alert function.

More on James and the Physical Basis of Emotion

We first present a reconstruction of James’s theory of emotion (JATE) and then argue for four theses: (a) Despite constructivist elements, James’s views are overall in line with basic emotions theory. (b) JATE does not exclude an influence of emotion on intentional action even in its original formulation; nevertheless, this influence is quite limited. It seems possible, however, to repair this problem of the theory. (c) Cannon’s theory of emotion is a centralized version of JATE that inherits from the latter theory a potentially fatal flaw, the insufficient physiological differentiation of emotions. (d) The core claim of JATE, that emotions are bodily feelings, is very likely false.

Physiological and psychological effects of ±-propranolol, +-propranolol and diazepam in induced anxiety

1 Four equal-sexed groups of eight normal subjects were given single doses of either (±)-propranolol (120 mg), (+)-propranolol (120 mg), diazepam (6 mg) or placebo using double-blind procedure and their effects studied under three types of experimental stress and at rest. 2 Finger tremor, EEG, averaged auditory evoked response, skin conductance, heart rate and respiratory rate were measured at each time of testing, and subjects also completed performance tests (reaction time, tapping speed and symbol copying) and subjective mood scales. 3 Neither (+)- nor (±)-propranolol had any beneficial effects on mood and physiological tests showed that, although adequate β-adrenoceptor blockade was achieved, there was no evidence of sedation. 4 Diazepam reduced subjective anxiety, significantly lessened the main amplitude of the auditory evoked response and also reduced the proportion of slower rhythms in the EEG. 5 The results suggest that (+)- and (±)-propranolol have no psychotropic effects on induced anxiety and that their modes of action are fundamentally different from that of diazepam.

Anger and fear: Separable effects of emotion and motivational direction on somatovisceral responses

We studied whether emotion (anger vs. fear) and motivational direction (approach vs. withdrawal) have specific, separable, and independent somatovisceral response patterns. Imagination scripts about soccer game episodes with crossed Emotion x Motivational Direction content resulting in four experimental groups were presented to a total of N = 118 active soccer players. Self-reports reflected the emotion but not the motivational direction induction. Univariate and multivariate analyses of 24 somatovisceral variables and 2 a priori defined summary variables showed that anger and fear had specific response profiles with effect sizes correlating r = 0.53 with the respective effect sizes from a previous study. Approach and withdrawal profiles varied only in intensity. Emotion and motivational direction did not interact and had independent somatovisceral effects. Results suggest that anger and fear have separate underlying neurobiological organizations each capable of bi-directional motivational tuning of efferent pathways. Results support the Component Model of Somatovisceral Response Organization.

Anxiolytic therapy with alprazolam increases muscle sympathetic activity in patients with panic disorders

Anxiolytic therapy with the benzodiazepine alprazolam is an established therapy in patients with panic disorder. Normally, panic-like anxiety and its concomitant physical symptoms quickly disappear under such treatment. Therefore we investigated whether there is a difference in sympathetic nervous system in patients with panic disorder compared to healthy controls. Three groups of subjects were included: ten patients with panic disorder, who received alprazolam and 20 healthy control subjects who were given either alprazolam (n=10) or matching placebo (n=10). Muscle sympathetic nerve activity (MSNA) and heart rate did not differ at baseline but significantly increased both in patients and healthy controls after intake of alprazolam (1 mg). However, in both groups both MSNA and heart rate were significantly elevated when compared to both baseline and the placebo control group. This study demonstrates (1) that anxiolytic therapy with alprazolam increases muscle sympathetic nerve activity and heart rate not only in patients with panic disorder but also in healthy controls and (2) that a significant difference in sympathetic nervous system activity between patients and controls, at baseline and during the therapy with alprazolam could not be demonstrated.

An autonomic flexibility–neurovisceral integration model of anxiety and cardiac vagal tone

Research on heart rate variability (HRV), cardiac vagal tone, and their relationship to anxiety is reviewed in the context of the autonomic flexibility and neurovisceral integration models of adaptive functioning. These perspectives address the qualities of response flexibility and inhibition across multiple levels, incorporating central and autonomic nervous system mechanisms of environmental engagement, as well as principles derived from non-linear dynamics. These models predict reduced HRV and vagal tone in anxiety, and the literature has generally supported this prediction, with exceptions as are noted. State, trait, and clinical expressions of anxiety are considered, along with the clinical, methodological, and theoretical implications of this research. A portrayal of anxiety as a restricted response range across biological and behavioral realms of functioning is drawn from the literature on anxiety and HRV.

A modern learning theory perspective on the etiology of panic disorder

Several theories of the development of panic disorder (PD) with or without agoraphobia have emerged in the last 2 decades. Early theories that proposed a role for classical conditioning were criticized on several grounds. However, each criticism can be met and rejected when one considers current perspectives on conditioning and associative learning. The authors propose that PD develops because exposure to panic attacks causes the conditioning of anxiety (and sometimes panic) to exteroceptive and interoceptive cues. This process is reflected in a variety of cognitive and behavioral phenomena but fundamentally involves emotional learning that is best accounted for by conditioning principles. Anxiety, an anticipatory emotional state that functions to prepare the individual for the next panic, is different from panic, an emotional state designed to deal with a traumatic event that is already in progress. However, the presence of conditioned anxiety potentiates the next panic, which begins the individual's spiral into PD. Several biological and psychological factors create vulnerabilities by influencing the individual's susceptibility to conditioning. The relationship between the present view and other views, particularly those that emphasize the role of catastrophic misinterpretation of somatic sensations, is discussed.

Panic disorder and the heart: a cardiology perspective

Panic disorder is a common condition that includes symptoms that may masquerade as a primary cardiovascular disorder. In addition, many patients with cardiovascular disease may also have panic disorder. To date, no definitive pathophysiological mechanism for panic disorder has been found; however, there are several hypotheses in the literature. Patients with syndrome X, coronary artery disease and/or palpitations, in addition to panic disorder all present to cardiologists. However, many patients go undiagnosed and ultimately place large costs on the health care system as a result. Panic disorder is a treatable condition, and cardiologists could easily identify patients with panic disorder and initiate appropriate therapy and/or referral.

Panic disorder in a patient with traumatic brain injury: a case report and discussion

Individuals that may be especially susceptible to panic attacks in the rehabilitation setting are patients who have suffered traumatic brain injuries, post-concussion syndrome, lesions, or encephalopathy. An individual is described who suffered a traumatic brain injury and was determined to have suffered a panic attack during his rehabilitation stay. The manifestations of panic attacks are described, using the case report as an example. The psychological aetiology of panic disorders is also reviewed, and treatment options using four major classes of neuropharmacologic agents: benzodiazepines, tricyclic antidepressants, monoamide oxidase inhibitors, and serotonin reuptake inhibitors, are discussed. Given the increasing incidence and survival of patients with traumatic brain injuries, the complications of panic attacks and disorders will become more important; they are a serious condition that can affect an individual's lifestyle, employment, and relationships, and increase the risk of suicide. Rehabilitation specialists should be aware of the manifestations and management of panic attacks and come to appreciate that recognition of this treatable condition is important during all stages of rehabilitation.

Epinephrine-induced panic attacks and hyperventilation

To assess the effects of epinephrine on ventilation in patients with panic disorder and in social phobics, analyses were performed on pooled data from two previous infusion studies. Throughout the infusion, changes in transcutaneous PCO2 (tcPCO2), subjective anxiety, heart rate and blood pressure were recorded continuously. Twenty-nine patients received epinephrine, ten patients received placebo. Thirteen patients (45%) had a panic attack during epinephrine. The fall in tcPCO2 and the cardiovascular response was greater in panicking patients than patients who did not panic. Although the fall in tcPCO2 associated with panic was not substantial and did not indicate clinically significant acute hyperventilation, it appears to be a sensitive index for epinephrine-induced panic. The fall in tcPCO2 was predicted rather by the frequency of occurrence of anxiety-related somatic symptoms than by the fear of these symptoms. These findings further reduce a role for fear of bodily sensations in epinephrine-induced panic attacks and favor a biological sensitivity to sympathetic stimulation.

Predictability, controllability, and fear of symptoms of anxiety in epinephrine-induced panic

BACKGROUND

Psychological manipulations (supplied information, safety cues) may influence panic rates during pharmacologic challenge tests in subjects with panic disorder (PD). Psychological panic models assume that fear of stress-related bodily sensations is central to the etiology of PD.

METHODS

Prior to infusion of epinephrine, 50 subjects with PD were randomly assigned to one out of four experimental conditions: with or without extensive information and with or without external control, according to a 2 x 2 design. The panic rate was hypothesized to be lower in subgroups possessing extensive information and/or control. Fear of bodily sensations was used as a predictor.

RESULTS

Thirty-four out of 50 patients (68%) panicked during the infusion. Subjects who received extensive information were marginally less likely to panic, but manipulation of control did not influence panic rates. Panickers did not differ from nonpanickers in measures of fear of fear. Anxiety sensitivity best predicted baseline anxiety and cognitive symptom scores, but was not associated with other outcome measures in panickers. Only baseline partial pressure of CO2 discriminated between panickers and nonpanickers.

CONCLUSIONS

Manipulating external safety cues appears to be of limited value in modulating responses to epinephrine challenge. Together with our finding that fear of anxiety symptoms does not predict panic rates, these data argue against "fear of fear" as a key mechanism in epinephrine-induced panic.

Sex differences in facial skin temperature when exposed to darkness with and without warning

The changes in skin temperature under anxiety were investigated by noninvasive measurements. The nasal skin temperature of 20 subjects was assessed by thermography. The measurement of the skin temperature by thermistor causes stress in subjects. The primary advantages of a thermography over use of a thermistor are noninvasive and accurate. Each subject was made anxious under the 2 conditions of sudden darkness (Sudden darkness condition) or experienced darkness (Experienced darkness condition). Under former, after a baseline facial skin temperature was established, the room light was suddenly turned off. The subject remained seated in darkness for 2 min. The time-series changes were significant for women, but not for men. For women, skin temperature significantly declined in sudden darkness. Experiments on experienced darkness were performed a week later. After a baseline facial skin temperature was established, the subject was told; "The room light would be turned off from now on, but please remain seated without moving". After the instruction, the room light was turned off. The subject remained seated in darkness for 2 min. The resultant time-series changes in skin temperatures were significant in neither men nor women.

Autonomic balance revisited: panic anxiety and heart rate variability

The analysis of heart rate variability (HRV) is becoming widely used in clinical research to provide a window into autonomic control of HR. This technique has been valuable in elucidating the autonomic underpinnings of panic disorder (PD), a condition that is marked by reports of heart palpitations. A body of research has emerged that implicates a relative reduction in HRV and cardiac vagal tone in PD, as indicated by various HRV measures. These data are consistent with the cardiac symptoms of panic attacks, as well as with developmental evidence that links high vagal tone with enhanced attention, effective emotion regulation, and organismic responsivity. Implications of these findings for nosology and pathophysiology are discussed. Reports of reduced HRV in PD contrast with portrayals of excess autonomic lability in anxiety. This contradiction is addressed in the context of traditional homeostatic models versus a systems perspective that views physiologic variability as essential to overall stability.

Epinephrine and fear of bodily sensations in panic disorder and social phobia

Fear of bodily symptoms of arousal has been implicated in the pathogenesis of both spontaneously occurring and experimentally provoked panic. Fear of bodily symptoms may be characteristic for panic disorder (PD) and is hypothesized to predict state anxiety and panic frequency during experimentally induced peripheral arousal. Twenty-eight subjects, 14 with PD and 14 with social phobia (SP) were infused with placebo and epinephrine (20, 40 and 80 ng/kg bodyweight/min) according to a fixed schedule in a single blind design. Fear of bodily symptoms was higher in subjects with PD, who also reported more bodily symptoms and higher state anxiety scores during the experiment. The panic rate (five out of 14), however, was the same in both groups. Panickers did not differ from non-panickers in trait- or baseline measures except for fear of bodily symptoms, which was marginally higher in panickers. Panickers showed greater reactivity in heart rate, diastolic blood pressure and capillary PCO(2). Our data do not support the hypothesis of a major role for fear of bodily symptoms in epinephrine-induced panic. Also, our results do not demonstrate a different reaction to epinephrine in PD and SP with situational panic attacks.

Comparison of bisoprolol and diazepam in the treatment of cardiac neurosis

In order to compare the beta blockers bisoprolol and diazepam in the treatment of cardiac neurosis, 40 patients (16 males and 24 females, mean age: 39 +/- 11 years) were examined in a double-blind, crossover study. Following a 4-week placebo period, patients were randomized to receive either bisoprolol 10 mg daily or diazepam 5 mg twice daily for 4 weeks. After a second 4-week washout period on placebo, patients were switched to the alternative regimen for a further 4 weeks. At the end of the placebo periods and during each phase of treatment, the following parameters were evaluated: somatic symptoms by self-assessment questionnaire, anxiety state by Hamilton rating scale, reaction time to both acoustic and visual stimuli, blood pressure, and heart rate. Both treatments were effective in reducing somatic symptoms of cardiac neurosis, but bisoprolol was significantly more effective than diazepam (p less than 0.01). On the contrary, diazepam was superior to bisoprolol in improving the Hamilton scale related to psychic symptoms. Only diazepam prolonged reaction times. Both treatments were well tolerated; however, 12 patients complained of drowsiness and nine of sedation under diazepam. In conclusion, bisoprolol appeared to be as effective as diazepam in the treatment of cardiac neurosis, but with better effects on somatic symptoms and without affecting patients' psychomotor performance.

Relation of hypocapnic symptoms to rate of fall of end-tidal PCO2 in normal subjects

Hyperventilation is of little clinical relevance unless it causes symptoms. These are often non-specific. Their threshold for onset and relation to steady level of arterial (or its equivalent, end-tidal PCO2; PETCO2) are uncertain, and it has been suggested that they may relate better to the rate of fall of PCO2 than to the absolute level. We investigated this in nine normal subjects, who breathed to and fro through a pneumotachograph into an open circuit in which the concentration of CO2 could be varied. Tidal volume, respiratory frequency and ventilation was measured on-line by a Compaq computer, and PETCO2 at the mouth was measured by capnograph. Subjects overbreathed at a fixed rate and depth until symptoms consisting of dizziness, paraesthesiae and light headedness occurred. Then, without their knowledge and while they continued to overbreathe, inspired CO2 was increased to restore PETCO2 to normal and abolish symptoms, and was then withdrawn again over either approximately 0.1, 2.5 or 5 min until symptoms were again reported. The PETCO2 at this point was noted. The three protocols were performed in each subject in a random order and the same symptoms were reported each time. When averaged across all subjects, symptoms occurred at mean PETCO2 values of 20.3, 19.2 and 18.6 mmHg (2.71, 2.56 and 2.48 kPa), respectively. These were not significantly different, and it can be concluded that there was no influence of rate of fall of PCO2 on threshold for symptoms. Chest pain only occurred in one subject and may have a different mechanism.

Attenuation of anxiety in ambulatory oral surgery patients with oral triazolam

The purpose of this investigation was to determine if the preoperative administration of an oral anxiolytic agent (triazolam) is beneficial in reducing the cardiovascular response to stress and anxiety. Twelve consecutive patients, six who received the drug and six who received a placebo, were monitored from the night before surgery at home until the morning with a Holter monitor. On presentation for surgery, levels of anxiety as well as heart rate and presence of cardiac arrhythmias were determined for the two groups. Patients who received the study medication had an anxiety level on the day of surgery similar to that recorded at an earlier consultation visit, whereas the placebo group showed a tendency toward an increase in anxiety on the day of surgery. There was a significant difference for resting heart rate between the two groups at various intervals associated with the preparation for the surgery. There were no complications related to the medication and, therefore, on the basis of this study, it appears that the administration of an oral anxiolytic agent prior to the patient presenting for surgery is beneficial in reducing the stress and anxiety associated with the operation as well as in reducing some of the cardiac manifestations of this stress.

Do instructions modify effects of beta-adrenoceptor blockade on anxiety?

To study the interaction between physiological and cognitive factors in anxiety, 44 subjects with public speaking anxiety were allocated to four different groups. Two groups received either beta-adrenoceptor blockade (100 mg of atenolol) or placebo orthogonally crossed with an instruction that heart rate would decrease or an instruction that did not mention cardiovascular effects. During the delivery of a speech, measures of heart rate, systolic and diastolic blood pressures, and self-reported anxiety were obtained. All variables increased during an anticipation period before speech, and heart rate, systolic blood pressure, and self-reported anxiety increased further during speech. Regardless of instructions, atenolol decreased heart rate and systolic blood pressure during both anticipation and speech, whereas no differences were found in self-reported anxiety. This lack of a relationship was seen in spite of the correctly perceived heart rate reduction in the atenolol-treated group receiving an instruction that heart rate would decrease. Cardiac aware subjects, according to the Autonomic Perception Questionnaire, showed higher levels of heart rate and self-reported anxiety at rest than did cardiac unaware subjects. During speech, even though heart rate was similar in atenolol treated groups, self-reported anxiety was higher in cardiac aware than in cardiac unaware subjects. The lack of a relationship between heart rate and self-reported anxiety is discussed in terms of primary and secondary emotions. It is suggested that the perception of external rather than internal cues determines situationally elicited anxiety.

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.

The pharmacology of human anxiety

The human pharmacology of anxiety disorders, including panic disorder, is detailed. The major theories center around the role of benzodiazepine receptor, noradrenergic and serotonergic dysfunction. The contribution that challenge tests with lactate, hyper- and hypocapnia, beta- and alpha-2-adrenoceptor agonists, peptides, pentylenetetrazol, and caffeine make to our understanding of the biological basis of anxiety and these major theories are described and discussed.

Noradrenergic function in generalized anxiety disorder: effects of yohimbine in healthy subjects and patients with generalized anxiety disorder

There is extensive preclinical and clinical support for the hypothesis that hyperactivity of noradrenergic neuronal systems is related to the pathophysiology of some forms of human anxiety. In the present investigation, the behavioral, biochemical, and cardiovascular responses to the alpha 2-adrenergic receptor antagonist, yohimbine, was determined in 20 patients with generalized anxiety disorder (GAD) and 20 healthy subjects. The responses to yohimbine were generally similar in the two groups except there was a trend for the yohimbine-induced increase in plasma 3-methoxy-4-hydroxyphenylglycol to be less in the GAD patients. These findings contrast with previous studies of the effects of yohimbine in panic disorder patients and, thereby, support a neurobiological distinction between these two disorders.

Lymphocyte beta-adrenergic receptor binding in panic disorder

Lymphocyte beta adrenergic receptor binding using [125I]CNP was determined in patients with panic disorder (N = 4) or agoraphobia with panic attacks (N = 17) and age- and sex-matched healthy subjects (N = 22). The patients showed a significantly lower number of beta-adrenergic receptor binding sites and a significantly higher affinity of binding than healthy subjects. A past or present history of major depression in the patients did not alter these findings. These results are consistent with a growing body of knowledge implicating noradrenergic dysfunction in the pathophysiology of panic anxiety.

The effects of diazepam and oxprenolol on short term memory in individuals of high and low state anxiety

1 The effect of oral doses of diazepam (5 mg) and oxprenolol (80 mg) on short term memory of normal individuals stratified for 'state' anxiety levels has been investigated. 2 Normal student volunteers were stratified into high and low anxiety groups on the basis of responses to the Spielberger 'A-state' scale. Subjects were then randomly administered active drug or placebo and given a form of running memory test performed under a variety of conditions in which variable rate of item presentation and articulatory suppression were used. 3 Diazepam significantly reduced the errors of recall in the running memory test in the high anxiety group and produced a distinct separation of response from the low anxiety group under the test conditions of slow item presentation with articulatory suppression. Oxprenolol had no effect on the short term memory test in either high or low anxiety groups in any experimental test situation. 4 These results are compared to previous work in which generally a deleterious effect of diazepam on short term memory in normal volunteers has been reported. The implications of these findings are further discussed in relationship to possible models of memory function.

Awareness of cardiac function in anxious, phobic and hypochondriacal patients

Awareness of pulse rate was tested in 60 psychiatric out-patients with anxiety, phobic or hypochondriacal neuroses by asking them to record how fast their hearts were beating during exposure to short film sequences. Correlations between subjective and objective heart rate (ECG) were significantly higher in anxious and hypochondriacal patients than in phobic ones. The results suggest that somatic symptoms in hypochondriacal and anxiety neurosis reflect increased awareness of bodily function.

Human endurance--mind or muscle?

Two investigations have been carried out. The first studied the effects of autonomic blockade on the cardiovascular response to a step test, a 50% maximum isometric grip test and a Valsalva manoeuvre: the step test was of 5 minutes duration and the other two for as long as possible. beta adrenergic blockade by propanolol diminished the blood pressure and pulse rate response to both the step test and isometric grip. The pulse rate response to the step test was also affected by cholinergic blockade with atropine. The response to the Valsalva test showed a cholinergic blockade effect of pulse rate alone and a blood pressure response alone on alpha adrenergic blockade by phenoxybenzamine. The second studied psychological stressing on physical and mental ability. A potential 'punishment' situation increased the blood pressure and pulse rate response to isometric grip while decreasing the time for which it could be maintained. A potential 'reward' situation increased both the maximum grip and the time for which 50% grip could be maintained. It is concluded that psychological factors can affect performance dependant on whether the situation is perceived as one of 'reward' or 'punishment'. A factor in the mediation of the adverse response is an inappropriate response of the autonomic nervous system.

Rock climbing: observations on heart rate and plasma catecholamine concentrations and the influence of oxprenolol

Observations are presented on the electrocardiogram and plasma catecholamine concentrations of 11 healthy men monitored during two rock climbing ascents. A placebo was administered prior to the first climb and an oral dose of the beta blocking agent oxprenolol ("Trasicor") prior to the second. Mean heart rates were 166 (+/- 20.4 SD) and 120 (+/- 10.2) respectively. Median plasma adrenaline concentrations were 0.05 microgram/1 and 0.33 microgram/1 before and after the climbs following the placebo. No significant difference was observed in the adrenaline concentrations before and after climbing following oxprenolol, or of noradrenaline concentrations on either occasion. These results are interpreted as suggesting that this popular sport represents more an anxiety-type of psychological stress than a physical stress and as such is likely to increase moral fibre rather than muscle fibre.

Biochemical evidence of anxiety in dental patients

Urinary metabolites before dental treatment were compared in a group of patients with dental phobia and in a matched control group. Plasma adrenaline, noradrenaline, and free fatty acids were estimated before treatment, immediately after sedation with diazapam 0.2 mg/kg body weight in the phobic patients, during induction of oral anaesthesia, and during and after surgery. Patients with dental phobia had significantly higher levels of adrenaline, which were only temporarily lowered by sedation, and which during treatment remained consistently higher than those of control patients.

Biogenic amines and emotion

The studies discussed here have shown a fairly consistent relationship between the effects of drugs on biogenic amines, particularly norepinephrine, and affective or behavioral states. Those drugs which cause depletion and inactivation of norepinephrine centrally produce sedation or depression, while drugs which increase or potentiate brain norepinephrine are associated with behavioral stimulation or excitement and generally have an antidepressant effect in man (Table 1). From these findings, a number of investigators have formulated the concept, designated the catecholamine hypothesis of affective disorders (6), that some, if not all, depressions may be associated with a relative deficiency of norepinephrine at functionally important adrenergic receptor sites in the brain, whereas elations may be associated with an excess of such amines. It is not possible either to confirm or to reject this hypothesis on the basis of currently available clinical data. Although there does appear to be a fairly consistent relationship between the effects of pharmacological agents on norepinephrine metabolism and on affective state, a rigorous extrapolation from pharmacological studies to pathophysiology cannot be made. Confirmation of this hypothesis must ultimately depend upon direct demonstration of the biochemical abnormality in the naturally occurring illness. It should be emphasized, however, that the demonstration of such a biochemical abnormality would not necessarily imply a genetic or constitutional, rather than an environmental or psychological, etiology of depression. Whereas specific genetic factors may be of importance in the etiology of some, and possibly all, depressions, it is equally conceivable that early experiences of the infant or child may cause enduring biochemical changes and that these may predispose some individuals to depressions in adulthood. It is not likely that changes in the metabolism of the biogenic amines alone will account for the complex phenomena of normal or pathological affect. Whereas the effects of these amines at particular sites in the brain may be of crucial importance in the regulation of affect, any comprehensive formulation of the physiology of affective state will have to include many other concomitant biochemical, physiological, and psychological factors. Although in this review of the relationship of biogenic amines to affective state relatively little has been said concerning the intricate set of environmental and psychological determinants of emotion, the importance of these factors must be stressed. The normally occurring alterations in affective state induced by environmental events is well known to all, from personal experience. The interactions between such environmental determinants of affect, various physiological factors, and the complexity of psychological determinants, including cognitive factors derived from the individual's remote and immediate past experiences, have received only limited study under adequately controlled conditions. It may be anticipated, however, that this will prove to be a particularly fruitful area for future research, for only within such a multifactorial framework may one expect to understand fully the relationship of the biogenic amines to emotional state.

Socio-economic background, aggression and catecholamine excretion

3 24-hr. urine samples were obtained from 27 volunteer army enlisted men on 3 consecutive days. The urine samples were analyzed for norepinephrine and epinephrine content and the results were related to selected socioeconomic background variables obtained from questionnaire responses of Ss. Individuals with low socio-economic backgrounds excreted significantly higher proportions of norepinephrine in relation to epinephrine than did individuals with middle-class backgrounds. Class differences in socialization of the child with respect to aggressiveness are hypothesized as leading to characteristic outwardly or inwardly aggressive behavior which has been shown previously to relate differentially to catecholamine excretion.