Increased brain serotonin turnover in panic disorder patients in the absence of a panic attack: reduction by a selective serotonin reuptake inhibitor

Since the brain neurotransmitter changes characterising panic disorder remain uncertain, we quantified brain noradrenaline and serotonin turnover in patients with panic disorder, in the absence of a panic attack. Thirty-four untreated patients with panic disorder and 24 matched healthy volunteers were studied. A novel method utilising internal jugular venous sampling, with thermodilution measurement of jugular blood flow, was used to directly quantify brain monoamine turnover, by measuring the overflow of noradrenaline and serotonin metabolites from the brain. Radiographic depiction of brain venous sinuses allowed differential venous sampling from cortical and subcortical regions. The relation of brain serotonin turnover to serotonin transporter genotype and panic disorder severity were evaluated, and the influence of an SSRI drug, citalopram, on serotonin turnover investigated. Brain noradrenaline turnover in panic disorder patients was similar to that in healthy subjects. In contrast, brain serotonin turnover, estimated from jugular venous overflow of the metabolite, 5-hydroxyindole acetic acid, was increased approximately 4-fold in subcortical brain regions and in the cerebral cortex (P < 0.01). Serotonin turnover was highest in patients with the most severe disease, was unrelated to serotonin transporter genotype, and was reduced by citalopram (P < 0.01). Normal brain noradrenaline turnover in panic disorder patients argues against primary importance of the locus coeruleus in this condition. The marked increase in serotonin turnover, in the absence of a panic attack, possibly represents an important underlying neurotransmitter substrate for the disorder, although this point remains uncertain. Support for this interpretation comes from the direct relationship which existed between serotonin turnover and illness severity, and the finding that SSRI administration reduced serotonin turnover. Serotonin transporter genotyping suggested that increased whole brain serotonin turnover most likely derived not from impaired serotonin reuptake, but from increased firing in serotonergic midbrain raphe neurons projecting to both subcortical brain regions and the cerebral cortex.     

Using Adult Learning Theory Concepts to Address Barriers to Cancer Genetic Risk Assessment in the African American Community

Utilization of cancer genetic risk assessment can be profoundly influenced by an individuals’ knowledge of risk assessment, attitudes regarding illness and healthcare, and affective reactions derived from social norms. Race and ethnicity play a powerful role in the development of an individual's attitudes and should be considered when attempting to understand a person's openness to cancer genetic risk assessment (Lannin et al., 1998). Until recently, however, cancer screening and prevention programs have been primarily based on data from studies conducted with the Caucasian population, yielding data that are not fully applicable to the African American community. In the last several years, research findings regarding African American's knowledge, attitudes, and feelings about genetic counseling and testing have grown (Matthews et al., 2000; Singer et al., 2004; Thompson et al., 2003). However, to the authors’ knowledge, these data have yet to be presented in a manner that both summarizes the barriers that African Americans have reported regarding cancer genetic risk assessment, while at the same time suggesting methods individual genetic counselors can utilize during community presentations to help address these barriers. This article will first summarize previous empirical findings regarding African Americans’ knowledge, attitudes, and feelings about cancer genetic risk assessment. The article will then apply adult learning theory to those findings to provide genetic counselors with practical, theory based techniques to apply toward community based educational programs with African American groups.     

Is death really the worm at the core? Converging evidence that worldview threat increases death-thought accessibility

According to terror management theory, if the cultural worldview protects people from thoughts about death, then weakening this structure should increase death-thought accessibility (DTA). Five studies tested this DTA hypothesis. Study 1 showed that threatening Canadian participants' cultural values (vs. those of another culture) increased DTA on a word-fragment completion task. Study 2 showed that when participants could dismiss the threat, DTA remained low. Study 3 replicated the results of Study 1, but DTA was measured using a lexical decision task. Response latencies to death, negative, and neutral content were measured. Worldview threat increased DTA relative to accessibility for negative and neutral content. Study 4 showed that the DTA effect emerged independently of the arousal of anger or anxiety. Finally, Study 5 demonstrated that participants with a pro-creation (vs. pro-evolution) worldview had higher DTA after reading an anti-creation article. Discussion focused on theoretical implications and directions for further research.     

Evidence That Self-Relevant Motives and Metaphoric Framing Interact to Influence Political and Social Attitudes

ABSTRACT— We propose that metaphor is a mechanism by which motivational states in one conceptual domain can influence attitudes in a superficially unrelated domain. Two studies tested whether activating motives related to the self-concept influences attitudes toward social topics when the topics' metaphoric association to the motives is made salient through linguistic framing. In Study 1, heightened motivation to protect one's own body from contamination led to harsher attitudes toward immigrants entering the United States when the country was framed in body-metaphoric, rather than literal, terms. In Study 2, a self-esteem threat led to more positive attitudes toward binge drinking of alcohol when drinking was metaphorically framed as physical self-destruction, compared with when it was framed literally or metaphorically as competitive other-destruction.     

On the optimality of serial and parallel processing in the psychological refractory period paradigm: Effects of the distribution of stimulus onset asynchronies

Within the context of the psychological refractory period (PRP) paradigm, we developed a general theoretical framework for deciding when it is more efficient to process two tasks in serial and when it is more efficient to process them in parallel. This analysis suggests that a serial mode is more efficient than a parallel mode under a wide variety of conditions and thereby suggests that ubiquitous evidence of serial processing in PRP tasks could result from performance optimization rather than from a structural bottleneck. The analysis further suggests that the experimenter-selected distribution of stimulus onset asynchronies (SOAs) influences the relative efficiency of the serial and parallel modes, with a preponderance of short SOAs favoring a parallel mode. Experiments varying the distribution of SOAs were conducted, and the results suggest that there is a shift from a more serial mode to a more parallel mode as the likelihood of short SOAs increases.     

A systematic examination of different parameters of presession exposure to tangible stimuli that maintain problem behavior

We examined the effects of three different presession conditions on tangibly maintained problem behavior for 2 students with autism, using individual-participant multielement designs. First, an analogue functional analysis demonstrated that problem behavior was maintained by access to tangible items. Next, topographies of item rejection were identified. Finally, students were exposed to (a) brief access, (b) no access, and (c) satiation to the tangible items prior to tangible sessions. The results demonstrated high levels of problem behavior following the brief-access and no-access presession conditions and low levels of problem behavior following the satiation condition. The findings are discussed in the context of how satiation might best be defined for these sorts of evaluations.     

Managing terror when self-worth and worldviews collide: Evidence that mortality salience increases reluctance to self-enhance beyond authorities

Terror management theory posits that one’s self-esteem and worldview operate jointly to manage mortality concerns. Accordingly, past research shows that mortality salience (MS) increases self-enhancement and worldview defense. The current research is the first to examine MS effects when self-enhancement threatens to undermine aspects of the worldview, in this case the credibility and status of worldview-representative authorities. MS led to reluctance to self-enhance following positive personality test feedback when the test was judged negatively by institutional authorities (Study 1a), as well as unwillingness to contradict self-esteem threatening feedback sanctioned by authorities (Study 1b). Mortality salient participants also rated themselves higher on valued dimensions unless it meant viewing themselves more positively than their parents (Study 2) and admired political icons (Study 3). Taken together, these results show that MS increases self-enhancement unless doing so challenges important representatives of the worldview. Theoretical and practical implications are discussed.     

Neuropsychological Assessment of HIV-Infected Populations in International Settings

Resource-limited regions of the world represent the areas most affected by the global HIV epidemic. Currently, there are insufficient data on the neurocognitive effects of HIV in these areas and neuropsychological studies that have been carried out thus far are marked by inconsistent methods, test batteries, and rating systems for levels of cognitive impairment. These differences in methods, along with genetic variability of both virus and host, differences in co-infections and other co-morbidities, differences in language and culture, and infrastructural deficiencies in many international settings create challenges to the assessment of neurocognitive functioning and interpretation of neuropsychological data. Identifying neurocognitive impairment directly attributable to HIV, exploring relationships between HIV-associated neurocognitive impairment, disease variables, and everyday functioning, evaluating differences in HIV-1 subtype associated neuropathology, and determining implications for treatment remain complicated and challenging goals. Endeavors to establish a more standardized approach to neurocognitive assessments across international studies in addition to accumulating appropriate normative data that will allow more accurate rating of neuropsychological test performance will be crucial to future efforts attempting to achieve these goals.     

What is the probability of replicating a statistically significant effect?

If an initial experiment produces a statistically significant effect, what is the probability that this effect will be replicated in a follow-up experiment? I argue that this seemingly fundamental question can be interpreted in two very different ways and that its answer is, in practice, virtually unknowable under either interpretation. Although the data from an initial experiment can be used to estimate one type of replication probability, this estimate will rarely be precise enough to be of any use. The other type of replication probability is also unknowable, because it depends on unknown aspects of the research context. Thus, although it would be nice to know the probability of replicating a significant effect, researchers must accept the fact that they generally cannot determine this information, whichever type of replication probability they seek.