The control of responsiveness in ADHD by catecholamines: evidence for dopaminergic, noradrenergic and interactive roles

We explore the neurobiological bases of attention deficit hyperactivity disorder (ADHD) from the viewpoint of the neurochemistry and psychopharmacology of the catecholamine-based behavioural systems. The contributions of dopamine (DA) and noradrenaline (NA) neurotransmission to the motor and cognitive symptoms of ADHD (e.g. hyperactivity, variable and impulsive responses) are studied in rodent and primate models. These models represent elements of the behavioural units observed in subjects with ADHD clinically, or in laboratory settings (e.g. locomotion, changed sensitivity/responsivity to novelty/reinforcement and measures of executive processing). In particular, the models selected emphasize traits that are strongly influenced by mesocorticolimbic DA in the spontaneously hypertensive (SHR) and the Naples high excitability (NHE) rat lines. In this context, the mode of action of methylphenidate treatment is discussed. We also describe current views on the altered control by mesolimbic catecholamines of appropriate and inappropriate goal-directed behaviour, and the tolerance or intolerance of delayed reinforcement in ADHD children and animal models. Recent insights into the previously underestimated role of the NA system in the control of mesocortical DA function, and the frontal role in processing information are elaborated.     

Development of orientation discrimination in infancy

It has previously been found by us, with a visual evoked potential (VEP) measure, that orientation discrimination of dynamic patterns in infants can be demonstrated from around 6 weeks after birth. Experiments are reported in which orientation discrimination was measured behaviourally, in two infant control habituation procedures, with both dynamic and static patterns. When dynamic patterns identical to those in our previous VEP studies were used, the first positive evidence of orientation discrimination was found at around 6 weeks postnatally. The time course of both the VEP and the behavioural measures was similar. However, with static patterns, evidence of orientation discrimination by newborns was found if the infants were allowed to compare the habituated and novel orientations in a paired simultaneous comparison after habituation, but was not found when the habituated and novel stimulus were presented sequentially. The positive evidence of orientation discrimination in newborns supports the hypothesis that some form of orientationally tuned detectors can be used for discrimination of static patterns at birth. However, some developmental change over several weeks seems to be required before a positive electrophysiological VEP response can be measured for dynamic patterns changing in orientation.     

Social representations of smoking and attitudes towards smoking restrictions in the Norwigian Navy

The present study investigated the relationship bewteen social representations about smokers and smoking, and attitudes towards smoking restrictions. Data were collected by means of questionnaires among a sample of employees ( n =4224)in the Norwegian Navy. Based on the results from first- and second-order principal components analyses, three dimensions of social representations were identified. The dimensions were labeled "negative representations", "positive representations" and "social influence". The three dimensions clearly differentiated between daliy, occasional and non-smokers. Further, structural equation modeling of the relation between social representations and attitudes towards smoking restrictions, indicated that social representations function as intermediating factors of the effect from smoking states upon attitudes towards smoking restrictions.
The findings indicate the need to focus upon social psyshological processes taking place in the ineraction between groups of smokers and non-smokers, as understanding of such processes may be relevant in preventing the development of group conflict.     

Happiness in Behaviour Genetics: An Update on Heritability and Changeability

In this paper we summarize recent behaviour genetic findings on happiness measured as life satisfaction (LS) and subjective wellbeing (SWB) and discuss important implications pertaining to stability and change, including the potential of individual and societal interventions. Broadly speaking, two main research strategies explore genetic and environmental influences on happiness, including quantitative and molecular genetics. Whereas molecular genetics seeks to trace the causal pathways from specific DNA variants, quantitative genetics estimates the magnitude of overall genetic and environmental influences without specifying actual DNA sequences and usually without specifying specific environmental circumstances. Molecular genetic studies have entered the happiness arena, but have shown mixed results. Most replicated findings are therefore based on quantitative genetics and derived from twin and family studies decomposing variation and co-variation into genetic, shared, and non-shared environmental sources. Recent meta-analyses of such studies report genetic influences (i.e., heritability) to account for 32–40 % of the variation in overall happiness (i.e., SWB, LS), and indicate that heritability varies across populations, subgroups, contexts and/or constructs. When exploring stable SWB levels, heritability is reported in the 70–80 % range, whereas momentary positive affect is often entirely situational. Happiness is thus heritable, stable, variable and changeable. What do these findings imply? Can happiness be raised as a platform in individuals and societies? We suggest that individual and societal interventions that target causal pathways and address both amplifying and compensatory processes (i.e., focus on developing strengths and mitigating risks)—thus providing for positive gene-environment matchmaking, are likely to be effective and longer lasting.     

What is so important about completing lives? A critique of the modified youngest first principle of scarce resource allocation

Ruth Tallman has recently offered a defense of the modified youngest first principle of scarce resource allocation [1]. According to Tallman, this principle calls for prioritizing adolescents and young adults between 15–40 years of age. In this article, I argue that Tallman’s defense of the modified youngest first principle is vulnerable to important objections, and that it is thus unsuitable as a basis for allocating resources. Moreover, Tallman makes claims about the badness of death for individuals at different ages, but she lacks an account of the loss involved in dying to support her claims. To fill this gap in Tallman’s account, I propose a view on the badness of death that I call ‘Deprivationism’. I argue that this view explains why death is bad for those who die, and that it has some advantages over Tallman’s complete lives view in the context of scarce resource allocation. Finally, I consider some objections to the relevance of Deprivationism to resource allocation, and offer my responses.     

Are Auditory Distractions Disturbing and Detrimental to the Performance of Expert Golfers? A Field Experiment

Although auditory distractions are prevalent and often seen as a threat to performance, relatively few studies have explored distraction effects in an applied sport context. This field experiment examined expert golfers' (n = 36) competitive performance in a normal and a distracting condition. The results displayed similar performance in the two conditions. Participants' responses to a postcompetition questionnaire generally suggested that they found auditory distractions below moderately disturbing and detrimental to their performance. Overall, our results contradict the popular consensus that distractions are disturbing and detrimental in motor performance contexts.     

Passive-aggressive (negativistic) personality disorder: a population-based twin study

The objective of this study was to investigate the familial aggregation of passive aggressive personality disorder (PAPD), and explore issues regarding PAPD raised by the DSM-IV Personality Disorder Work Group. Two thousand seven hundred and ninety-four Norwegian twins from the population-based Norwegian Institute of Public Health Twin Panel were interviewed with the Structured Interview for DSM-IV Personality (SIDP-IV). Because of the rarity of the twins meeting full diagnostic criteria for PAPD a dimensional representation of the disorder was used for the analyses. Overlap with other axis II disorders was assessed by polychoric correlations, while familial aggregation was explored by structural equation twin models. Overlap was highest with paranoid (r = 0.52) and borderline personality disorder (r = 0.53), and lowest with schizoid (r = 0.26). Significant familial aggregation was found for PAPD. The twin correlations and parameter estimates in the full model indicated genetic and shared environmental effects for females, and only shared environmental effects for males, but the prevalence of endorsed PAPD criteria in this community sample was too low to permit us to conclude with confidence regarding the relative influence of genetic and shared environmental factors on the familial aggregation of PAPD.     

Adolescent adjustment and well-being: effects of parental divorce and distress

This study investigates the long-term effects of parental divorce on adolescent psychological adjustment and well-being, and to what extent the effects are accounted for by parental psychological distress. Data were collected among 8,984 Norwegian adolescents (13-19 years) and their parents. Outcome variables were symptoms of anxiety and depression, subjective well-being, and three areas of school problems. Parental divorce was found to be associated with both higher mean levels and larger variances in adolescent problems. Divorce and parental distress contributed independently to adolescent distress, supporting the notion of "double exposure" effects. The prevalence of adolescents with substantial distress symptoms was 14% among those with non-distressed non-divorced parents and 30% among those with divorced and distressed parents. In general effects remained when controlling for demographic factors. Long-term effects of divorce on symptoms of anxiety and depression were stronger among girls than among boys.     

Multifractal analyses of response time series: A comparative study

Response time series with a non-Gaussian distribution and long-range dependent dynamics have been reported for several cognitive tasks. Conventional monofractal analyses numerically define a long-range dependency as a single scaling exponent, but they assume that the response times are Gaussian distributed. Ihlen and Vereijken (Journal of Experimental Psychology: General, 139, 436–463, 2010) suggested multifractal extensions of the conventional monofractal analyses that are more suitable when the response time has a non-Gaussian distribution. Multifractal analyses estimate a multifractal spectrum of scaling exponents that contain the single exponent estimated by the conventional monofractal analyses. However, a comparison of the performance of multifractal analyses with behavioral variables has not yet been addressed. The present study compares the performance of seven multifractal analyses. The multifractal analyses were tested on multiplicative cascading noise that generates time series with a predefined multifractal spectrum and with a structure of variation that mimics intermittent response time variation. Time series with 1,024 and 4,096 samples were generated with additive noise and multiharmonic trends of two different magnitudes (signal-to-noise/trend ratio; 0.33 and 1). The results indicate that all multifractal analysis has individual pros and cons related to sample size, multifractality, and the presence of additive noise and trends in the response time series. The summary of pros and cons of the seven multifractal analyses provides a guideline for the choice of multifractal analyses of response time series and other behavioral variables.