Regional cerebral blood flow during experimental phobic fear

Positron emission tomographic measurements of regional cerebral blood flow (rCBF) were used to investigate central nervous system correlates of fear and anxiety. Volunteers with symptomatic snake phobia were studied while exposed to visual phobogenic, aversive, and neutral stimuli. Anxiety ratings and the number of nonspecific electrodermal fluctuations increased as a function of phobic stimulation. Phobic, compared to neutral and aversive, stimulation elevated rCBF in the visual associative cortex. The basal ganglia were not activated more by phobic than aversive or neutral stimulation. However, cortical and thalamic rCBF were always correlated during phobic but not aversive or neutral stimulation. This indicates that the thalamus could be a relay station for phobic stimulus processing and affect.     

Virtual reality for the psychophysiological assessment of phobic fear: Responses during virtual tunnel driving.

An overall assessment of phobic fear requires not only a verbal self-report of fear but also an assessment of behavioral and physiological responses. Virtual reality can be used to simulate realistic (phobic) situations and therefore should be useful for inducing emotions in a controlled, standardized way. Verbal and physiological fear reactions were examined in 15 highly tunnel-fearful and 15 matched control participants in 3 virtual driving scenarios: an open environment, a partially open tunnel (gallery), and a closed tunnel. Highly tunnel-fearful participants were characterized by elevated fear responses specifically during tunnel drives as reflected in verbal fear ratings, heart rate reactions, and startle responses. Heart rate and fear ratings differentiated highly tunnel-fearful from control participants with an accuracy of 88% and 93%, respectively. Results indicate that virtual environments are valuable tools for the assessment of fear reactions and should be used in future experimental research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A factor analysis of personality and fear variables in phobic disorders.

Investigated the fears and personality traits of 225 individuals (mean age 32.5 yrs) experiencing 1 of 4 phobic conditions—agoraphobia, claustrophobia, social phobia, or some other specific phobia. Several Fear Survey Schedule variables and the personality scales of the Guilford-Zimmerman Temperament Survey were factor analyzed. Five factors were extracted that were consistent with previous findings, which were related to each of 4 independent variables: Treatment Subgroup, Diagnosis, Age, and Sex. Clinic and private clients did not differ significantly on any factor, nor did age account for any meaningful change in factor scores. The diagnostic groups scored discrepantly on 2 factors: Social Activity and Cognitive Introversion, and Fear of Sensory Stimuli. Females differed significantly from males on Femininity and Miscellaneous Fears. Results are discussed in terms of past research and possible ramifications for the clinical practice of behavior therapy. (French abstract) (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Additive and interactive effects of stimulus degradation: No challenge for CDP+.

[Correction Notice: An erratum for this article was reported in Vol 35(2) of Journal of Experimental Psychology: Learning, Memory, and Cognition (see record 2009-02753-020). The URL for the supplemental material was incomplete. The complete URL is http:dx.doi.org/10.1037/a0013738.supp.] S. O'Malley and D. Besner (2008) showed that additive effects of stimulus degradation and word frequency in reading aloud occur in the presence of nonwords but not in pure word lists. They argued that this dissociation presents a major challenge to interactive computational models of reading aloud and claimed that no currently implemented model is able to simulate additive effects in these conditions. In the current article, it is shown that the connectionist dual process model (CDP+) can simulate these effects because its nonlexical route is thresholded. The authors present a series of simulations showing that CDP+ can not only simulate the precise dissociation observed by O'Malley and Besner but more generally can produce additive effects for a wide range of parameter combinations and different sets of items. The nonlexical route of CDP+ was not modified post hoc to deal with the effects of stimulus quality, but it had been thresholded for principled reasons before it was known that these effects existed. Together, the effects of stimulus quality on word frequency do not challenge CDP+ but rather provide unexpected support for its architecture and processing dynamics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Selective effects of naltrexone on food pleasantness and intake

The effects of 50 mg naltrexone on both pleasantness and intake of 10 common food items were investigated using a double-blind placebo-controlled study with 16 male volunteers. Rated food pleasantness was reduced significantly in the naltrexone condition compared with both controls (placebo and baseline). However, pleasantness ratings were not affected uniformly across foods, with sweetened, fatty, and high-protein foods being most affected. Changes in rated unpleasantness generally mirrored those for pleasantness, but evaluations of saltiness and sweetness were unaffected by naltrexone. Although total intake was reduced in the naltrexone condition, this was not significant compared with placebo. However, fat and protein intakes were significantly less following naltrexone. The effect of naltrexone on intake was also food dependent, but in this case intake of sweet foods was spared relative to other food categories. The apparent discrepancy between liking and intake data with sweet foods could be interpreted in terms of the likely influence of normal eating styles on food selection during a buffet-style meal, and may explain some contradictions in previous studies of this kind. The implications for understanding opioid involvement in food acceptability are discussed.     

Effects of uncertainty about the behavior of a phobic stimulus on subjects' fear reactions.

19 rat-phobic female college students were repeatedly exposed to a live rat on a nearby platform under instructional conditions designed to induce different expectancies about the probability of the rat remaining on the platform. Although the rat's behavior was the same in both conditions, Ss who were led to believe that the rat might leave the platform evidenced significantly greater cognitive and physiological arousal to repeated rat exposures than did Ss who were informed that the rat would definitely not leave the platform. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the automatic nature of phobic fear: Conditioned electrodermal responses to masked fear-relevant stimuli.

Normal Ss (n?=?64) were exposed either to pictures of snakes and spiders or to pictures of flowers and mushrooms in a differential conditioning paradigm in which one of the pictures signaled an electric shock. In a subsequent extinction series, these stimuli were presented backwardly masked by another stimulus for half of the Ss, whereas the other half received nonmasked extinction. In support of a hypothesis that suggests that nonconscious information-processing mechanisms are sufficient to activate responses to fear-relevant stimuli, differential skin conductance response to masked conditioning and control stimuli was obvious only for Ss conditioned to fear-relevant stimuli. These results were replicated in a 2nd experiment (n?=?32), which also demonstrated that the effect was unaffected by which visual half-field was used for stimulus presentation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Short-term effects of naltrexone in 155 heroin ex-addicts

The narcotic antagonist naltrexone was administered for periods of up to 8 months to a total of 155 patients at a dose of 40-200 mg per day. The antagonistic effect of naltrexone was tested by injections of heroin. Eighty milligrams of natrexone was effective for 48hr. The antagonistic effect decreased at 72 hr after the administration of 120-200 mg of naltrexone. Laboratory tests indicated no signs of toxicity. Naltrexone may elicit an increase in blood pressure and opigastric pain. Neither of these side effects appear clinically important. No signs of dependence on naltrexone were detected. These results suggest that naltrexone may be useful for clinical treatment of opiate dependence.     

The effects of fear arousal and suppression of fear upon social perception.

A research was designed to study the effects of fear arousal and suppression of fear upon social perception. "It was hypothesized that individuals subjected to a fear-producing situation would tend to project their feelings upon some social objects, and further, instructions to inhibit emotional reactions would increase the amount of projection." Sixty male volunteers from introductory psychology classes were randomly assigned to one of three groups: Control, Fear-Expression and Fear-Suppression. "The data indicate that the arousal of fear results in a tendency to project fear onto a stimulus object in the environment. The results are also consistent with the hypothesis that suppression facilitates the tendency to project although, in this latter instance, one is less confident in rejecting the null hypothesis. Several alternative explanations of the effects of the suppression variable were considered and the role of cognitive variables in the projection process were discussed." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using analog baselines to assess the effects of naltrexone on self-injurious behavior

Healthy male and female human volunteers were exposed to 50 ppm or 100 ppm trichloroethylene (Tri) by inhalation for 4 h. Blood and urine samples were taken at various times before, during, and after the exposure period for analysis of glutathione (GSH), related thiols and disulfides, and GSH-derived metabolites of Tri. The GSH conjugate of Tri, S-(1,2-dichlorovinyl)glutathione (DCVG), was found in the blood of all subjects from 30 min after the start of the 4-h exposure to Tri to 1 to 8 h after the end of the exposure period, depending on the dose of Tri and the sex of the subject. Male subjects exposed to 100 ppm Tri exhibited a maximal content of DCVG in the blood at 2 h after the start of the exposure of 46.1 +/- 14.2 nmol/ml (n = 8), whereas female subjects exposed to 100 ppm Tri exhibited a maximal content of DCVG in the blood at 4 h after the start of the exposure of only 13.4 /- 6.6 nmol/ml (n = 8). Pharmacokinetic analysis of blood DCVG concentrations showed that the area under the curve value was 3.4-fold greater in males than in females, while the t1/2 values for systemic clearance of DCVG were similar in the two sexes. Analysis of the distribution of individual values indicated a possible sorting, irrespective of gender, into a high- and a low-activity population, which suggests the possibility of a polymorphism. The mercapturates N-acetyl-1,2-DCVC and N-acetyl-2,2-DCVC were only observed in the urine of 1 male subject exposed to 100 ppm Tri. Higher contents of glutamate were generally found in the blood of females, but no marked differences between sexes were observed in contents of cyst(e)ine or GSH or in GSH redox status in the blood. Urinary GSH output exhibited a diurnal variation with no apparent sex- or Tri exposure-dependent differences. These results provide direct, in vivo evidence of GSH conjugation of Tri in humans exposed to Tri and demonstrate markedly higher amounts of DCVG formation in males, suggesting that their potential risk to Tri-induced renal toxicity may be greater than that of females.     

The effects of changing contexts on return of fear following exposure therapy for spider fear.

Treatment of specific fears and phobias is sometimes followed by a return of fear. Work with rats has provided evidence that a greater return of fear occurs when a conditioned stimulus extinguished in 1 context is later presented in a different context than if presented in the same context in which it was originally extinguished. In the present study. 36 human participants who were highly afraid of spiders received 1 session of exposure therapy (with participant modeling) and were then tested for return of fear 1 week later in either the same or a different context. It was hypothesized that there would be a greater return of fear in those participants treated and followed up in different contexts than in those treated and followed up in the same context. Participants tested in a novel context at follow-up showed a greater return of fear than participants tested in the same context. Limitations and areas for future study are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The verbal threat information pathway to fear in children: The longitudinal effects on fear cognitions and the immediate effects on avoidance behavior.

Verbal information has long been assumed to be an indirect pathway to fear. Children (aged 6-8 or 12-13 years) were exposed to threat, positive, or no information about 3 novel animals to see the long-term impact on their fear cognitions and the immediate impact on avoidance behavior. Their directly (self-report) and indirectly (implicit association task) measured attitudes toward the animals changed congruent with the information provided, and the changes persisted up to 6 months later. Verbal threat information also induced behavioral avoidance of the animal. Younger children formed stronger animal- threat and animal-safe associations because of threat and positive verbal information than older children, but there were negligible age effects on self-reported fear beliefs and avoidance behaviors. These results support theories of fear acquisition that suppose that verbal information affects components of the fear emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of conscientiousness and agreeableness on job performance.

The authors hypothesized that the relationship between conscientiousness and job performance would be stronger for persons high in agreeableness than for those low in agreeableness. Results of hierarchical moderated regression analyses for 7 independent samples of employees across diverse occupations provided support for the hypothesis in 5 of the samples. In samples supporting the hypothesis, among the highly conscientious workers, those low in agreeableness were found to receive lower ratings of job performance than workers high in agreeableness. One explanation for lack of an interaction between conscientiousness and agreeableness in the other 2 samples is that those jobs were not characterized by frequent, cooperative interactions with others. Overall, the results show that highly conscientious workers who lack interpersonal sensitivity may be ineffective, particularly in jobs requiring cooperative interchange with others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of positive affect and conscientiousness on strain.

The purpose of our study was to more fully investigate a combination of personal resources, namely positive affect (PA) and conscientiousness, on emotional exhaustion, depersonalization, and job tension. We examined a sample of nurses employed by a metropolitan hospital and found that the combination of high positive affect and high levels of conscientiousness was associated with lower levels of all strain variables. Our findings suggested that conscientiousness strengthened the negative relationship between PA and job strain. Our results were consistent with the view that some dispositions can act as resources protecting individuals from experienced stress. Implications of these results, strengths and limitations, and directions for future research are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The interactive effects of belongingness and charisma on helping and compliance.

This study tests the main and interactive effects of belongingness and perceived charismatic leadership on 2 forms of organizational citizenship behavior (helping and compliance). In line with expectations, a study of 115 manager-subordinate dyads demonstrates that employees show more helping (manager rated) when they have a stronger sense of belongingness at work and more helping as well as compliance when they perceive their leader to be more charismatic (subordinate rated). Belongingness partially mediates the relationship between charisma and helping. Also, as hypothesized, belongingness and charisma have interactive effects on employees' helping and compliance. The impact of perceived charisma on these behaviors is stronger for employees with a low sense of belongingness at work than for individuals with a higher sense of belongingness. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The interactive effects of proactive personality and work-family interference on well-being.

Proactive personality was expected to moderate the relationship between controllable work and nonwork stressors (e.g., time-based work-family interference) and job/life satisfaction. Moderated multiple regression analyses of survey data from a sample of professionals (N=133) revealed a significant interaction between time-based family interfering-with work and proactive personality predicting life satisfaction and several main effects offering partial support for the hypothesized relationships (α     

Repressive and defensive coping during fear and anger.

In this study, the relationship between repressive and defensive coping styles and somatovisceral responses as well as emotion self-reports were investigated in 2 situational contexts conceived to induce fear and anger. Anxiety (State-Trait Anxiety Inventory; L. Laux, P. Glanzmann, P. Schaffner, and C. D. Spielberger, 1981) x Defensiveness (Marlowe-Crowne Social Desirability Scale; D. P. Crowne and D. Marlowe, 1960) x Emotion (fear, anger) moderated regression analyses revealed that compared with baseline during fear, defensiveness was related to a decrease in heart rate variability. Also during fear, repressive-defensive copers had lower self-reports of negative affect but showed higher behavioral negative affect (m. corrugator reactivity) than other participants. During anger, defensiveness was positively related to both diastolic blood pressure reactivity and m. zygomaticus reactivity. Additional analyses showed that emotional responses of repressive-defensive copers were strongly moderated by the situational context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extinction in fear conditioning: effects on startle modulation and evaluative self-reports

gamma-Hydroxybutyric acid (GHB) is unfamiliar to many physicians in the United States but enjoys clinical use elsewhere for applications in resuscitation, anesthesia, and addiction therapy. Use within the United States is restricted to Food and Drug Administration-approved clinical trials for treatment of narcolepsy. Recently illicit use of GHB has emerged within the United States where it is distributed for purported euphoric and "fat-burning" metabolic effects. Clinical effects can be severe, progressing rapidly to respiratory arrest and death. We provide an updated comprehensive review of the literature with particular emphasis on toxicology, including GHB pharmacodynamics, clinical effects, and suggestions for overdose management. Recommended management of acute GHB intoxication includes prevention of aspiration, use of atropine for persistent symptomatic bradycardia, consideration of neostigmine as a reversal agent, and treatment for coingested substances. Emergency physicians are urged to become familiar with GHB because of its potential for severe morbidity as well as its potential use as a future resuscitative agent.