HIV infection associated post-traumatic stress disorder and post-traumatic growth--a systematic review

The phenomenon of post-traumatic stress has been well documented in the literature as a lasting mental health condition associated with exposure to traumatic life events. The diagnosis and experience of human immunodeficiency virus (HIV) disease may be such a trauma. On the other hand, the phenomenon of post-traumatic growth (PTG) has been described, whereby people show positive mental health growth in the face of such trauma. This systematic review was set out to explore post-traumatic stress disorder (PTSD) and PTG in people with HIV to monitor prevalence, measurement and efficacy of interventions to reduce stress and/or promote growth. Standardised review techniques were used to track reports on both PTSD and PTG. A total of 206 papers were retrieved from the PTSD and HIV searches, and 13 from the PTG and HIV searches. After reviewing the papers for inclusion according to adequacy and relevance criteria and to remove duplicates, 33 PTSD papers and three PTG were available for full coding. Prevalence of PTSD in HIV ranged from 5% to 74%, which were much greater than the 7-10% in the general population. Seven studies showed a relation between trauma and PTSD, while six showed a link between PTSD diagnosis and reduced antiretroviral treatment adherence. Women were more likely to be diagnosed with PTSD. Only three intervention reports were identified that fitted our inclusion criteria. All of these reported on psychological interventions for HIV+?individuals with trauma. The interventions utilised HIV education, training in coping techniques and support groups. Only coping interventions were shown to be effective. PTG was under researched but showed a promising avenue of study. There needs to be harmonised measurement and the evidence base would need strengthening in order to build on the understanding of the impact of PTSD and PTG over the course of HIV disease. There is good evidence to associate HIV diagnosis and experiences during the course of illness as traumatic. PTSD has been shown to be prevalent and there seems to be good evidence to incorporate standardised measures to track the course of the disorder. There is extremely limited evidence that interventions may affect the course of symptom experience. The evidence and insight into PTG show promise but is currently inadequate.     

Behavioral momentum and the law of effect

In the metaphor of behavioral momentum, the rate of a free operant in the presence of a discriminative stimulus is analogous to the velocity of a moving body, and resistance to change measures an aspect of behavior that is analogous to its inertial mass. An extension of the metaphor suggests that preference measures an analog to the gravitational mass of that body. The independent functions relating resistance to change and preference to the conditions of reinforcement may be construed as convergent measures of a single construct, analogous to physical mass, that represents the effects of a history of exposure to the signaled conditions of reinforcement and that unifies the traditionally separate notions of the strength of learning and the value of incentives. Research guided by the momentum metaphor encompasses the effects of reinforcement on response rate, resistance to change, and preference and has implications for clinical interventions, drug addiction, and self-control. In addition, its principles can be seen as a modern, quantitative version of Thorndike's (1911) Law of Effect, providing a new perspective on some of the challenges to his postulation of strengthening by reinforcement.     

Temporal context in concurrent chains: I. Terminal-link duration

Two experiments are reported in which the ratio of the average times spent in the terminal and initial links (Tt/Ti) in concurrent chains was varied. In Experiment 1, pigeons responded in a three-component procedure in which terminal-link variable-interval schedules were in constant ratio, but their average duration increased across components by a factor of two. The log initial-link response ratio was a negatively accelerated function of Tt/Ti. Overall, the data were well described by Grace's (1994) contextual choice model (CCM) with temporal context represented as (Tt/Ti)k or 2Tt/(Tt + Ti), and by Mazur's (2001) hyperbolic value-added model (HVA), with each model accounting for approximately 93% of the variance. In Experiment 2, fixed-parameter predictions for each model were generated, based on the data from Experiment 1, for conditions in which Tt/Ti was varied over a more extreme range. Data were consistent with the predictions of CCM with temporal context represented as 2Tt/(Tt + Ti) and to a lesser extent as (Tt/Ti)k, but not with HVA. Overall, these results suggest that preference increases as a hyperbolic function of Tt/Ti when terminal-link duration is increased relative to initial-link duration, with the terminal-link schedule ratio held constant.     

Development and validation of a Client Problem Profile and Index for drug treatment

The development of the Client Problem Profile and Index are described, and initial concurrent and predictive validity data are presented for a sample of 547 patients in outpatient methadone treatment. Derived from the TCU Brief Intake for drug treatment admissions, the profile covers 14 problem areas related to drug use (particularly cocaine, heroin/opiate, marijuana, other illegal drugs, and multiple drug use), HIV risks, psychosocial-functioning, health, employment, and criminality. Analyses of predictive validity show the profile and its index (number of problem areas) were significantly related to therapeutic engagement, during-treatment performance, and posttreatment follow-up outcomes. Low moderate to high moderate effect sizes were observed in analyses of the index's discrimination.     

DOES SENSITIVITY TO MAGNITUDE DEPEND ON THE TEMPORAL DISTRIBUTION OF REINFORCEMENT?

Our research addressed the question of whether sensitivity to relative reinforcer magnitude in concurrent chains depends on the distribution of reinforcer delays when the terminal-link schedules are equal. In Experiment 1, 12 pigeons responded in a two-component procedure. In both components, the initial links were concurrent variable-interval 40-s variable-interval 40-s, and the terminal links were both 20-s interval schedules in which responses were reinforced by either 4-s of grain in one, or 2-s of grain in the other. The only difference between the components was whether the terminal-link schedules were fixed interval or variable intervals. For all subjects, the relative rate of responding in the initial links for the terminal link that produced the 4-s reinforcer was greater when the terminal links were fixed-interval schedules than when they were variable-interval schedules. This result is contrary to the prediction of Grace's (1994) contextual choice model, but is consistent with both Mazur's (2001) hyperbolic value-added model and Killeen's (1985) incentive theory. In Experiment 2, 4 pigeons responded in a concurrent-chains procedure in which 4-s or 2-s reinforcers were provided independently of responding according to equal fixed-time or mixed-time schedules. Preference for the 4-s reinforcer increased as the variability of the intervals comprising the mixed-time schedules was decreased. Generalized-matching sensitivity of initial-link response allocation to relative reinforcer magnitude was proportional to the geometric mean of the terminal-link delays.     

Attributional inference across cultures: similar automatic attributions and different controlled corrections

Five studies examined the automatic and controlled components of attributional inference in U.S. and East Asian (EA) samples. Studies 1 through 3 used variations of the "anxious woman" paradigm, manipulating the inferential goal (dispositional or situational) and the normative impact of situational constraint information (discounting or augmenting). In each study, U.S. and EA participants under cognitive load produced strong automatic attributions to the focus of their inferential goal (dispositional or situational). Compared with the U.S. cognitive load participants, U.S. no load participants corrected their attributions according to the normative rules of inference. In contrast, EA no load participants corrected in the direction of situational causality, even when the specific content of the situational information provided should have promoted stronger dispositional inferences. Studies 4 and 5 examined and ruled out alternative accounts. Results are discussed in terms of a situational causality heuristic present in EA individuals.     

Resistance to extinction in the steady state and in transition

Three experiments with pigeons explored the constancy of reinforcer omission during extinction conjectured by rate estimation theory. Experiment 1 arranged 3-component multiple variable-interval (VI) schedules with a mixture of food and extinction trials within each session. Reinforcers omitted to an extinction criterion increased with food-trial reinforcer rate. Experiment 2 arranged 3-component multiple VI schedules where components differed in rate or number of reinforcers. Resistance to extinction depended on the training reinforcer rate but not on the number of reinforcers omitted. Experiment 3 replicated the partial-reinforcement extinction effect within subjects in a discrete-trial procedure and found that more reinforcers were omitted in continuous- than in partial-reinforcement trials. A model of extinction based on behavioral momentum theory accounted for all the data.     

Activation of adenosine receptors in the posterior cingulate cortex impairs memory retrieval in the rat

Adenosine A1 and A2A receptor agonists and antagonists have been reported to alter learning and memory. The aim of our study was to investigate the involvement of adenosinergic system in memory retrieval into posterior cingulate cortex (PCC) of Wistar rats. To clarify this question, we tested specifics agonist and antagonists of adenosine A1 and A2A receptors in rats submitted to a one-trial inhibitory avoidance task. The stimulation of adenosine A1 and A2A receptors by CPA and CGS21680, respectively, impaired memory retrieval for inhibitory avoidance task, into PCC. These findings provide behavioral evidence for the role of adenosinergic system in the memory retrieval into PCC.     

Factor analysis of the frontal systems behavior scale (FrSBe)

The Frontal Systems Behavior Scale (FrSBe), formerly called the Frontal Lobe Personality Scale (FLOPS), is a brief behavior rating scale with demonstrated validity for the assessment of behavior disturbances associated with damage to the frontal-subcortical brain circuits. The authors report an exploratory principal factor analysis of the FrSBe-Family Version in a sample including 324 neurological patients and research participants, of which about 63% were diagnosed with neurodegenerative diseases (Huntington's, Parkinson's, and Alzheimer's diseases). The three-factor solution accounted for a modest level of variance (41%) and confirmed a factor structure consistent with the three subscales proposed on the theoretical basis of the frontal systems. Most items (83%)from the FrSBe subscales of Apathy, Disinhibition, and Executive Dysfunction loaded saliently on three corresponding factors. The FrSBe factor structure supports its utility for assessing both the severity of the three frontal syndromes in aggregate and separately.