ADHD Correlates, Comorbidity, and Impairment in Community and Treated Samples of Children and Adolescents

Patterns of correlates, comorbidity and impairment associated with attention-deficit hyperactivity disorder (ADHD) in children and youth were examined in representative samples from the community and from treatment facilities serving medically indigent youth in Puerto Rico. Information from caretakers and youths was obtained using the Diagnostic Interview Schedule for Children, (version IV), measures of global impairment, and a battery of potential correlates. In the community (N = 1,896) and the treated samples (N = 763), 7.5 and 26.2% of the children, respectively, met criteria for DSM-IV ADHD in the previous year. Although the prevalence rates and degree of impairment differed, the general patterns of correlates, comorbidity and impairment were similar in both populations. The exceptions were associated with conduct disorder, anxiety, impairment in the ADHD comorbid group, and age factors that appeared to be related to selection into treatment.     

Underlying dimensions of ecocentric and anthropocentric environmental beliefs

This study focuses on the cognitive components of general environmental attitudes. Taking as a starting point the scale of Thompson and Barton (1994) to identify ecocentric and anthropocentric motives in environmental conservation, the beliefs that guide attitudes in the person-environment relationship are analyzed. Confirmatory factor analysis was used to contrast the tripartite structure of these beliefs--based on egoistic, socioaltruistic, and biospheric aspects-with a two-dimensional structure that confronts ecocentric and anthropocentric orientations. The results obtained from two samples, a student sample (n = 212) and a sample from the general population of Madrid (n = 205), indicate the existence of a three-dimensional structure of environmental beliefs: an anthropocentric dimension based on the instrumental value of the environment for human beings, a biospheric dimension that values the environment for its own sake, and, lastly, an egobiocentric dimension that values the human being within nature as a whole.     

Depression and cocaine dependence

Presence of depression in cocaine-dependent users is relevant for treatment of these persons. This study assessed the presence of depressive symptomatology with a published Spanish translation of the Beck Depression Inventory for a sample of 115 Spanish cocaine-dependent users who were in outpatient treatment at Centers of Drug Dependence of Galicia, Spain. The mean score was 13.7 (SD = 10.3), with 24.3% of the sample having scores which indicate clinical depression (cut off > or =21). These data underscore the need to assess the presence of depression in cocaine-dependent users who require treatment.     

Cholinergic afferents to the locus coeruleus and noradrenergic afferents to the medial septum mediate LTP-reinforcement in the dentate gyrus by stimulation of the amygdala

Transient long-term potentiation (E-LTP) can be transformed into a long-lasting LTP (L-LTP) in the dentate gyrus (DG) by behavioral stimuli with high motivational content. Previous research from our group has identified several brain structures, such as the basolateral amygdala (BLA), the locus coeruleus (LC), the medial septum (MS) and transmitters as noradrenaline (NA) and acetylcholine (ACh) that are involved in these processes. Here we have investigated the functional interplay among brain structures and systems which result in the conversion of a E-LTP into a L-LTP (reinforcement) by stimulation of the BLA (BLA-R). We used topical application of specific drugs into DG, and other targets, while following the time course of LTP induced by stimulation of the perforant pathway (PP) to study their specific contribution to BLA-R. One injection cannula, a recording electrode in the DG and stimulating electrodes in the PP and the BLA were stereotactically implanted one week before electrophysiological experiments. Topical application of atropine or propranolol into the DG blocked BLA-R in both cases, but the effect of propranolol occurred earlier, suggesting a role of NA within the DG during an intermediate stage of LTP maintenance. The injection of lidocaine into the LC abolished BLA-R indicating that the LC is part of the functional neural reinforcing system. The effect on the LC is mediated by cholinergic afferents because application of atropine into the LC produced the same effect. Injection of lidocaine inactivating the MS also abolished BLA-R. This effect was mediated by noradrenergic afferents (probably from the LC) because the application of propranolol into the MS prevented BLA-R. These findings suggest a functional loop for BLA-R involving cholinergic afferents to the LC, a noradrenergic projection from the LC to the DG and the MS, and finally, the cholinergic projection from the MS to the DG.     

Working memory deficits in transgenic rats overexpressing human adenosine A2A receptors in the brain

Adenosine receptors in the central nervous system have been implicated in the modulation of different behavioural patterns and cognitive functions although the specific role of A(2A) receptor (A(2A)R) subtype in learning and memory is still unclear. In the present work we establish a novel transgenic rat strain, TGR(NSEhA2A), overexpressing adenosine A(2A)Rs mainly in the cerebral cortex, the hippocampal formation, and the cerebellum. Thereafter, we explore the relevance of this A(2A)Rs overexpression for learning and memory function. Animals were behaviourally assessed in several learning and memory tasks (6-arms radial tunnel maze, T-maze, object recognition, and several Morris water maze paradigms) and other tests for spontaneous motor activity (open field, hexagonal tunnel maze) and anxiety (plus maze) as modification of these behaviours may interfere with the assessment of cognitive function. Neither motor performance and emotional/anxious-like behaviours were altered by overexpression of A(2A)Rs. TGR(NSEhA2A) showed normal hippocampal-dependent learning of spatial reference memory. However, they presented working memory deficits as detected by performance of constant errors in the blind arms of the 6 arm radial tunnel maze, reduced recognition of a novel object and a lack of learning improvement over four trials on the same day which was not observed over consecutive days in a repeated acquisition paradigm in the Morris water maze. Given the interdependence between adenosinic and dopaminergic function, the present results render the novel TGR(NSEhA2A) as a putative animal model for the working memory deficits and cognitive disruptions related to overstimulation of cortical A(2A)Rs or to dopaminergic prefrontal dysfunction as seen in schizophrenic or Parkinson's disease patients.     

Modes of executive control in sequence learning: from stimulus-based to plan-based control

The authors argue that human sequential learning is often but not always characterized by a shift from stimulus- to plan-based action control. To diagnose this shift, they manipulated the frequency of 1st-order transitions in a repeated manual left-right sequence, assuming that performance is sensitive to frequency-induced biases under stimulus- but not plan-based control. Indeed, frequency biases tended to disappear with practice, but only for explicit learners. This tendency was facilitated by visual-verbal target stimuli, response-contingent sounds, and intentional instructions and hampered by auditory (but not visual) noise. Findings are interpreted within an event-coding model of action control, which holds that plans for sequences of discrete actions are coded phonetically, integrating order and relative timing. The model distinguishes between plan acquisition, linked to explicit knowledge, and plan execution, linked to the action control mode.     

Family communication styles, attitude towards institutional authority and adolescents' violent behaviour at school

The purpose of present study is to analyse the relationship among certain family and school factors, adolescents' attitude towards institutional authority, and violent behaviour at school. The sample is composed of 1049 adolescents of both sexes and aged from 11 to 16 years old. Statistical analyses were carried out using structural equation modelling. Results indicate a close association between negative communication with father and violent behaviour in adolescence. Moreover, data suggest that teachers' expectations affect students' attitude towards institutional authority, which in turn is closely related to school violence. Finally, findings show an indirect influence of father, mother and teacher in adolescents' violent behaviour, mainly through their effect on family- and school-self-concept.     

Affect and depression in the elderly

Depression is considered one of the most complex mental disorders in the elderly. The diagnostic difficulties due to comorbidity, especially, with somatic diseases, have cast doubt on the use of diagnostic instruments for the elderly. In the present study, we try to determine the existence of differences in affect of third-age depression with respect to adult-age depression. For this purpose, the PANAS-X scale was administered to 120 subjects (30 depressive patients over 65 years old, 30 depressive patients between 25 and 50, and two control groups of 30 people each). The data allow us to establish two major differences of depression in the elderly compared to depression in adults: a lower intensity of negative affect and a lower intensity in the affects of fear, hostility and guilt. We can also conclude that sadness is not a differentiating element between both depressive groups.     

Psychological profile of potential organ donors and non-organ donors

The aim of this research was to analyse the psychological profile of potential organ donors and potential non-organ donors, from a sample of people with qualifications lower than a Bachelor's degree. The variables examined were prosocial behaviour, the scales of the Constructive Thinking Inventory, and the dimensions of personality of the Big-Five Questionnaire. The results show that non-organ donors have a lower score in prosocial behaviour, are less efficient in their actions, with a tendency for less thought before acting, and they tend to be prejudiced. The results also reveal that this group has lower degrees of cooperation and empathy. They tend to be less reflective, less scrupulous, less willing to persevere in their actions, less interested in culture, and less open to new ideas and values. The above results are discussed, bearing in mind the utility of this knowledge to professionals dedicated to organ donation.