Clamped Corticosterone (B) Reveals the Effect of Endogenous B on Both Facilitated Responsivity to Acute Restraint and Metabolic Responses to Chronic Stress

To determine the effects of both corticosterone (B) and chronic stressors on acute ACTH responses to restraint, young male rats were exposed to streptozotocin-induced diabetes, cold (5-7 degreesC) or intracerebroventricular (icv) neuropeptide Y (NPY) for 5 d and then exposed to restraint within 2 h after lights on. Two groups of rats were studied: intact and adrenalectomized replaced with B pellets that maintained plasma B in the normal mean 24-h range of intact rats. In addition to ACTH and B responses to restraint on d 5, body weight, food intake, fat depots, glucose and other hormones were measured to determine the role of stress-induced elevations in B on energy balance. ACTH responses to restraint were normal in intact rats subjected to diabetes or cold. By contrast, there was no ACTH or B response to restraint in NPY-infused intact rats. All 3 groups of chronically stimulated adrenalectomized rats with clamped B had facilitated ACTH responses to restraint compared to their treatment controls. Overall food intake increased in all groups of stressed rats; however, augmented intake occurred only during the light in intact rats and equally in the light and dark in B-clamped rats. White adipose depot weights were decreased by both diabetes and cold and increased by NPY in intact rats; the decreases with cold and increases with NPY were both blunted and changes in fat stores were not significant in adrenalectomized, B-clamped rats. We conclude that: 1. diabetes- and cold-induced facilitation of restraint-induced afferent input to hypothalamic control of the hypothalamo-pituitary-adrenal (HPA) axis is opposed in intact rats by the elevated feedback signal of B secretion; 2. NPY does not induce facilitation of afferent stress pathways; 3. chronic stimulation of the HPA axis induces acute hyperresponsiveness of hypothalamic neurons to restraint provided that the afferent input of this acute stimulus is not prevented by B feedback; 4. stimulus-induced elevations in B secretion result in day-time feeding; 5. insensitivity of both caloric efficiency and white fat stores to chronic stress in adrenalectomized, B-clamped rats results from loss of normally variable B levels.     

Does the Beck Anxiety Inventory measure anything beyond panic attack symptoms?

The Beck Anxiety Inventory (BAI) has become a popular measure in anxiety assessment and the BAI does not overlap in content with measures of depression. There is also some factor analytic evidence to support this distinction. However, an inspection of the BAI's content indicates that many of its items resemble, or are identical to, the symptoms of panic attacks listed in the DSM-IV. Further empirical support for this suspicion is provided from the results of a factor analysis of the BAI items and the individual DSM-IV panic symptoms contained in the Panic Attack Questionnaire, using data from a sample of 157 panic disorder patients. A three-factor model (dizziness related, catastrophic cognitions/fear, cardiorespiratory distress) emerged that replicated a three-factor model of panic symptoms identified in earlier work with another panic disorder sample. All but one of the BAI items loaded highly on the three panic symptom clusters and no separate BAI factor was obtained. The BAI appears to be confounded with, or actually measures, panic attacks rather than anxiety in general. Several implications of this finding are discussed.     

The Millon Adolescent Personality Inventory profiles of depressed adolescents

The evidence indicates that adolescent depression may be more difficult to recognize than its adult counterpart, although the reasons for this difficulty remain unclear. The research in this area is in part impeded by the lack of adolescent-specific measures of personality functioning. In this study the personality styles, expressed concerns, and behavioral tendencies of depressed adolescents were investigated by means of the Millon Adolescent Personality Inventory (MAPI), a relatively new personality inventory designed specifically for this age group. Three hundred sixty-six high school students completed the Beck Depression Inventory (BDI) and the MAPI, resulting in 332 valid and reliable MAPI profiles. The data were reduced to two factors, accounting for 65.1% of the total variance, by means of a principal components analysis. The two factors were interpreted as two dimensions of personality functioning associated with depression in adolescents. The first dimension suggested a socially withdrawn, overtly recognizable depression, whereas the second presents acting-out tendencies that may overshadow depressive symptomatology. The findings are integrated with the theoretical positions represented in the literature. Theoretical and practical implications for the use of the MAPI with depressed adolescents are discussed.     

Environmental stress and blood glucose change in insulin-dependent diabetes mellitus

Blood glucose (BG) response to psychological stress in insulin-dependent diabetes mellitus (IDDM) patients has not been firmly established. We report a study designed to address the gaps and methodological difficulties reviewed. Subjects with IDDM were exposed to two sessions (12 weeks apart) of two 20-min standardized stressors (active and passive) and a control condition administered in counterbalanced order. To measure BG response, subjects were connected to a glucose/insulin infusion system providing continuous BG measurement. Mood checklist measures were obtained at prestressor, poststressor, and recovery periods. During the first session of testing, the active stressor was associated with significantly more absolute change in BG response than the passive stressor. Results also indicate that IDDM subjects' BG response to this active stressor was idiosyncratic but significantly reliable over time.     

The effects of physostigmine during the acquisition of avoidance behaviour as a function of the intersession interval

Rats were trained and tested on an avoidance task in a shuttle box. The change in the performance of the control rats over two sessions was found to be a U-shaped function of the interval between the sessions. The change in performance of rats injected with physostigmine prior to the second session was also found to be a U-shaped function of the intersession interval, although the drug was shown to impair avoidance behaviour. These results are consistent with those of Hamburg (1967) and of Biederman (1970), and support the general contention that cholinergic mechanisms in the brain are involved in the control of avoidance and escape behaviour in the rat. They do not, however, necessarily support the hypothesis advanced by Deutsch (1969, 1971) to describe a biochemical basis of learning and memory, especially if it is used to explain the effects of cholinesterase inhibitors on avoidance behaviour in the shurtlebox.     

Some Effects of Reduction of Extra-Classroom Crowding in a School Environment

The effects of reduced enrollment were studied by examining two architecturally identical schools. One school experienced a 43% reduction in enrollment while the other's enrollment remained constant. Reduction in enrollment had a number of positive benefits, including improved attitudes about the school environment and reduced faculty absenteeism. Findings regarding academic performance were less clear.     

Spectral content as a cue to perceived auditory distance.

Changes in the spectral content of wide-band auditory stimuli have been repeatedly implicated as a possible cue to the distance of a sound source. Few of the previous studies of this factor, however, have considered whether the cue provided by spectral content serves as an absolute or a relative cue. That is, can differences in spectral content indicate systematic differences in distance even on their first presentation to a listener, or must the listener be able to compare sounds with one another in order to perceive some change in their distances? An attempt to answer this question and simultaneously to evaluate the possibly confounding influence of changes in the sound level and/or the loudness of the stimuli are described in this paper. The results indicate that a decrease in high-frequency content (as might physically be produced by passage through a greater amount of air) can lead to increases in perceived auditory distance, but only when compared with similar sounds having a somewhat different high-frequency content, ie spectral information can serve as a relative cue for auditory distance, independent of changes in overall sound level.