Cardiovascular and symptomatic reduction effects of alprazolam and imipramine in patients with panic disorder: results of a double-blind, placebo-controlled trial

Seventy-nine patients with panic disorder were randomized to an 8-week double-blind treatment with alprazolam, imipramine, or placebo. Patients kept daily records of panic attacks, activity, anxiety, sleep, and medication use. Weekly measures of anxiety, depression, somatic symptoms, fears, avoidance, disability, and improvement were obtained. All patients underwent a symptom-limited exercise treadmill and other cardiovascular measures. By physician and patient global assessment, patients receiving alprazolam or imipramine were significantly better than patients on placebo. The alprazolam effects were apparent by week 1; the imipramine effects by week 4. All groups showed significant reductions in anxiety, depression, somatic measures, and panic attack frequency. At 8 weeks, patients in the alprazolam group reported significantly less fear than patients in the other two groups. Subjects in the imipramine group showed a significant increase in heart rate and blood pressure.

Dietary and hormonal evaluation of men at different risks for prostate cancer: plasma and fecal hormone-nutrient interrelationships

Relationships between dietary nutrients and plasma and fecal estrone, estradiol-17 beta, testosterone, and plasma prolactin concentrations were studied in young Seventh-day Adventist men: 18 nonvegetarians (NVs), 20 lactoovovegetarians (LOVs), and 15 vegans (V). Blood samples and 3-d dietary records were obtained. Contemporaneously collected diet composites and stool samples were analyzed for fiber. Vs and LOVs consumed significantly more fiber than did the omnivores, whereas NVs and LOVs consumed more saturated fatty acids than did Vs. Although plasma steroid-hormone status did not differ, Vs had significantly higher fecal estrogen concentrations than did NVs or LOVs. Plasma prolactin concentrations were significantly higher in NVs and LOVs than in Vs. Significant relationships were observed for the combined groups between dietary and fecal fiber components and fecal, but not plasma, steroid hormones. For the combined groups, prolactin concentrations were positively correlated with saturated fatty acid intake. Further research on the effects of dietary nutrients on endocrine homeostasis in other age groups is warranted.

Guttman scaling in agoraphobia: cross-cultural replication and prediction of treatment response patterns

The Fear and Avoidance Scales (FAS) is an 11-item questionnaire consisting of two subscales that measure features of agoraphobia and claustrophobia and that were demonstrated to be valid Guttman scales in a British clinical population. The purposes of the study reported here were to replicate the scale characteristics in the United States and to determine if improvement during treatment would follow the sequence predicted by the hierarchy implied in the scales. The FAS was given to 25 female agoraphobics before and after behavioural treatment. A principal components analysis replicated the agoraphobia and claustrophobia factors established in the British sample. Scalogram analyses showed that the Claustrophobia subscale of the FAS was a valid Guttman scale in the US sample whereas the Agoraphobia subscale yielded a high coefficient of reproducibility but a low coefficient of scalability. Treatment reduced the patients' fears and avoidances in the predicted sequence since for both scales the hierarchy of items remained unchanged following treatment.

Use of medication and in vivo exposure in volunteers for panic disorder research

A survey of 794 subjects volunteering for studies of panic disorder with or without phobic avoidance revealed that fewer than 15% had received imipramine and fewer than 15% had undergone in vivo exposure, although the majority had engaged in some form of counseling and had used benzodiazepines. Subjects with spontaneous panic attacks reported more avoidance than subjects with situational attacks. One-half of the subjects were unemployed. The authors recommend wider use of the available effective treatments for panic disorder and phobic avoidance.

P3 in schizophrenia is affected by stimulus modality, response requirements, medication status, and negative symptoms

Eighteen schizophrenics who were not taking medication, 13 schizophrenics who were taking medication, and 37 age-matched controls were tested with event-related potential paradigms designed to elicit P3 response automatically or effortfully (ie, with a choice reaction time task). Electroencephalograms were recorded from the 19 standard 10-20 electrode sites. Compared with controls, both groups of schizophrenics had reduced P3 amplitudes for both effortful and automatic paradigms. P3 latencies were delayed relative to controls for the medication-taking schizophrenics in the effortful paradigms. Negative symptoms derived from the Brief Psychiatric Rating Scale within 1 week of event-related potential testing correlated negatively with both auditory and visual P3 amplitude in the subjects who were not taking medication. There was no evidence that P3 is smaller over left temporal electrode sites in schizophrenics, as has been reported by others. P3 amplitude reduction in schizophrenia is a robust psychobiological phenomenon that is present regardless of medication status or task demands.

Cognitive aspects of panic attacks. Content, course and relationship to laboratory stressors

Twenty patients with panic attacks and ten controls were given a standardised interview about thoughts occurring during times of anxiety or panic attacks. The interviewer was blind to the subject's diagnosis. The 20 panic patients underwent a psychophysiological test battery which included a cold pressor test, mental arithmetic task, and 5.5% CO2 inhalation. More patients than controls reported thoughts centered on fears of losing control and shame when anxious. Panic patients rated their thoughts as stronger and clearer than did controls and they had more difficulty excluding them from their minds. A feeling of anxiety preceded anxious thoughts in patients. This suggests that 'faulty cognitions' are not the initial event in a panic attack, although anxious thoughts may exacerbate or maintain them. Significant correlations were found between the intensity of anxiety-related thoughts in anticipation of mental arithmetic and changes in diastolic blood pressure and heart rate during mental arithmetic.

Plasma lipid levels in patients with panic disorder or agoraphobia

Plasma lipids were measured in 102 subjects with panic disorder or agoraphobia. In women, but not men, a significantly higher than expected number of subjects had cholesterol values that exceeded the 75th percentile of national reference values for their sex and age.

Autonomic changes after treatment of agoraphobia with panic attacks

Twenty-three patients meeting DSM-III criteria for agoraphobia with panic attacks and 14 age-, race-, and sex-matched nonanxious controls were tested in the laboratory and on a test walk in a shopping mall. The patients were tested before and after about 15 weeks of treatment with placebo and exposure therapy, imipramine and exposure therapy, or imipramine and initial antiexposure instructions. Controls were tested twice at a similar interval, but without any treatment. On test day 1, patients compared to controls showed higher average heart rate and skin conductance levels and greater numbers of skin conductance fluctuations in the laboratory, and higher heart rates before and during the test walk. Between pretreatment and posttreatment tests, clinical ratings improved and skin conductance levels decreased in all treatment groups. Heart rate levels in the laboratory, on the other hand, decreased in patients on placebo and rose in patients on imipramine. Thus, imipramine compromises the usefulness of heart rate as a measure of emotional arousal. Higher pretreatment heart rates predicted greater clinical improvement.

Mitral valve prolapse and panic disorder: a review of their relationship

There has been considerable speculation about a possible relationship between panic disorder and mitral valve prolapse syndrome (MVP), although empirical results have been highly inconsistent. Some studies report low frequencies of 0-8%, others high frequencies of 24-35% "definite" MVP in panic patients (average across 17 studies: 18% of panic patients, 1% of normal controls). Elevated prevalences of MVP were also reported for generalized anxiety disorder, bipolar affective disorder, and anorexia nervosa. Studies of MVP patients generally failed to find elevated prevalence of panic compared to other cardiac patients or normal controls (averages across seven studies: 14%, 10%, and 8%, respectively). Inconsistent results may be due to widely different diagnostic criteria for MVP, low reliability of this diagnosis, inadequate control groups, "non-blind" ratings of panic or MVP, and sampling bias in both patient and control populations. These problems as well as the great variations in the published results preclude any final judgment. If there is concomitance between MVP and panic, it is small and primarily involves subjects with milder or reversible variants of MVP. At present it seems most justified, however, to assume co-morbidity in highly symptomatic individuals rather than a functional relationship.

Treadmill exercise test and ambulatory measures in panic attacks

Treadmill exercise test performance and ambulatory heart rate and activity patterns of 40 patients with panic attacks were compared with 20 age-matched controls (control group 1) and 20 nonexercising controls (control group 2). All patients underwent a symptom-limited exercise stress test. Panic attack patients and control group 1 wore an ambulatory heart rate/activity monitor for up to 3 days. Panic patients had a significantly higher heart rate at 4 and 6 METS than either control group. The max METS were 11.2 +/- 2.3, 13.5 +/- 2.3 and 11.2 +/- 1.8 for the panic attack patients and control groups 1 and 2, respectively. One panic patient had ischemia on the treadmill at 12 METS. Panic patients had a significantly higher standing heart rate than controls. Furthermore, 11 of 39 panic patients had tachycardia on standing compared with 3 of 40 controls. Panic attack patients had higher wake and sleep heart rates than control group 1, but the differences were not significant. These results are consistent with autonomic dysfunction in panic patients but may also be due to differences in physical conditioning. The treadmill can be useful for reassuring patients and for identifying the rare patient with ischemia on exercise.

Panic attacks in the natural environment

Despite much recent research, there is still little systematic information about the phenomenology of panic attacks, and their possible causes remain obscure. We investigated panic attacks in the natural environment using an event sampling approach. Twenty-seven panic attack patients and 19 matched normal controls kept panic attack and self-exposure diaries for 6 days and wore an ambulatory heart rate/physical activity recorder for 3 days. Patients reported 175 attacks, generally of moderate severity. The most frequent symptoms were palpitations, dizziness/lightheadedness, dyspnea, nausea, sweating, and chest pain/discomfort. The results did not support the classification of panic attacks recently proposed by Sheehan and Sheehan, which requires three symptoms as a cutoff for panic attacks. Panic attacks classified by the patients as situational (i.e., occurring in feared situations) were more severe and occurred in situational contexts different from spontaneous attacks, but were otherwise phenomenologically similar. Heart rates did not change during spontaneous attacks and were only mildly elevated during situational attacks or during the 15 minutes preceding these attacks. These heart rate changes were interpretable as effects of anxiety, although physical activity showed a similar pattern of changes. Some normal control subjects reported on the panic diary primarily situational anxiety episodes that were phenomenologically similar to, albeit less severe than, the patients' episodes. Panic patients may sometimes fail to perceive environmental triggers for their attacks because many attacks classified as spontaneous occurred in classical "phobic" situations. Furthermore, the comparison of concurrent diary and retrospective interview and questionnaire descriptions showed that panic patients have a tendency toward retrospective exaggeration. Implications for the assessment, definition, and classification of panic attacks are discussed.

Serum phosphate and anxiety in major depression

Serum inorganic phosphate was measured in 33 hospitalized patients with unipolar depression. As predicted, serum phosphate showed significant negative correlations with Minnesota Multiphasic Personality Inventory scales sensitive to anxiety (Psychasthenia: -0.33) and somatic concern (Hypochondriasis: -0.51). This is consistent with previous observations of relative hypophosphatemia in patients with panic disorder. Clinical consequences of relative hypophosphatemia and the possible roles of hyperventilation or elevated peripheral catecholamines as mediators of this effect are discussed.

Panic-disordered subjects' perceptions of film: a repertory grid study

Clinical research into panic attacks over the past two decades has led to the hypothesis that panic-disordered subjects may have a lower threshold to separation anxiety than normals. This hypothesis was investigated by measuring panic-disordered and normal subjects' reactions to viewing a film of a potentially anxiety-provoking situation. The extent to which individuals construe film through identification with the narrative's characters was also examined. To gauge these reactions a repertory grid was administered to 11 subjects with a history of panic disorder and 12 controls after they had watched a half-hour episode from a feature film in which a divorced couple fight acrimoniously over custody of their 17-yr.-old daughter. Five elements were characters mentioned in the film and two were of 'self,' one in a secure and another in an insecure situation. Ten constructs were elicited by a triadic sorting procedure and four were supplied. Ratings of elements on all constructs were subjected to a principal components analysis (INGRID). While the construals of the two groups were essentially similar, there were differences between them in terms of the perceived salience of the film's characters. Panic-disordered subjects also construed themselves as more insecure than did the normals. The results affirm the use of the repertory grid in the study of panic disorder and in the analysis of the perception of filmed events.

Autonomic characteristics of agoraphobia with panic attacks

We compared electrodermal and heart rate measures of autonomic activation between patients meeting DSM-III criteria for agoraphobia with panic attacks and controls in terms of tonic level, reactivity to various types of stimuli, recovery, habituation, and spontaneous variability. The most striking differences between groups in the laboratory were higher tonic levels of skin conductance and heart rate among patients. Patients' heart rates were also tonically elevated in a test situation outside the laboratory. Certain measures of habituation and spontaneous variability also differed between groups, but there were only weak and inconsistent differences in reactivity to, or recovery from, stimuli with diverse qualities of novelty, startlingness, intensity, or phobicity. The elevated activation levels may be signs of a chronic state or may be phobic responses to the testing situations. A minority of patients failed to show these elevated levels.

Lactate infusions and panic attacks: do patients and controls respond differently?

Ten patients with panic disorder or agoraphobia with panic attacks and 10 normal controls received infusions of normal saline (placebo) and sodium lactate in a single-blind design. The time course of changes in the dependent variables was closely monitored, and expectancy biases and demand characteristics were minimized. Lactate increased self-reported anxiety and heart rate equally in patients and controls. The only variables showing statistically different responses between the groups were systolic and diastolic blood pressure. Overall, in both groups, the effects of lactate were quite similar to states of natural panic or anxiety for both self-report measures and heart rate. Patients had a tendency to endorse somatic symptoms indiscriminately. Our data do not support response to lactate as a biological marker of proneness to panic attacks.

Ambulatory heart rate changes in patients with panic attacks

Of 33 "panic" attacks reported by patients wearing an ambulatory solid-state heart rate/activity monitor for 6 days, 19 (58%) occurred at heart rates disproportionate to activity levels and different enough from surrounding heart rates to indicate a distinct physiologic state. Intense panic attacks with three or more symptoms were the most readily identified. ECG monitoring found the elevated heart rates to be sinus tachycardias. Heart rate elevation did not occur during anticipatory anxiety episodes. Ambulatory heart rate recordings confirm the presence of major physiologic changes during self-reported panic attacks.

Sodium lactate infusions and panic attacks: a review and critique

Response to sodium lactate infusions has been proposed as an experimental model and a biologic marker for panic attacks. Several authors have claimed that patients suffering from panic attacks, but not normal controls, "panic" in response to lactate. A careful review of methods and results of 13 studies, however, reveals serious methodologic problems, lack of specificity and sensitivity, and a failure to consider cognitive variables. When baseline differences are ruled out, the responses of patients and controls may not differ. So far, response to lactate cannot be interpreted as a model and marker for panic attacks and does not provide evidence for their underlying biologic distinctness from other types of anxiety. Known biologic mechanisms do not sufficiently explain the effects of lactate. Instead, an interaction of peripheral physiologic changes, past experience, environmental cues, and their appraisal as threatening or dangerous seems to be a more appropriate model.

ERPs and Psychopathology. I. Behavioral process issues

The clinical study of ERPs has an inherent defect--a self-selection of clinical populations that hampers equating of clinically defined groups on factors extraneous to the independent variables. Such ex post facto studies increase the likelihood of confounding variables in the interpretation of findings. Hence, the development of lawful relationships between clinical variables and ERPs is impeded and the fulfillment of description, explanation, prediction, and control in brain science is thwarted. Proper methodologies and theory development can increase the likelihood of establishing these lawful relationships. One methodology of potential value in the clinical application of ERPs, particularly in studies of aging, is that of divided attention. Two promising theoretical developments in the understanding of brain functioning and aging are the distraction-arousal hypothesis and the controlled-automatic attention model. The evaluation of ERPs in the study of brain-behavior relations in clinical populations might be facilitated by the differentiation of concurrent, predictive, content, and construct validities.