La importancia de las emociones en los períodos sensibles del desarrollo = The importance of emotions in sensitive developmental periods

Investigaciones recientes sugieren que en la adolescencia tienen lugar importantes cambios en la estructura,bioquímica y fisiología del cerebro que podrían explicar la dificultad que experimentan los adolescentes en elcontrol de sus emociones así como también otros rasgos de su comportamiento inestable. En este artículo presentamosalgunas investigaciones que establecen, asimismo, una correlación entre las reorganizaciones cerebrales quetienen lugar en el primer año de vida con signos de irritabilidad y desazón emocional que muestra el bebédurante este periodo. En ambos casos la dificultad de controlar los impulsos emocionales es susceptible de afectarla relación de los padres con el niño o joven. Discutimos la posible relevancia de esta coincidencia dentro de unaperspectiva evolucionista así como la posible vulnerabilidad de estos períodos. Finalmente, apuntamos la necesidadde una teoría integradora del desarrollo humano y ofrecemos algunos puntos de debate

Eating disorders, weight perception, and dieting in adolescence

Background: Eating disorders are serious psychiatric disorders, which usually have their onset in adolescence. Body dissatisfaction and dieting, both common among adolescents, are recognised risk factors for eating disorders. The aim of the present study was to assess the prevalence of eating disorders in the general adolescent population, assess the risk of developing eating disorders in subgroups of dieters, and analyse longitudinal concomitants of incorrect weight perception. Method: A prospective follow-up study on 595 adolescents, aged 15 at baseline, was conducted in western Finland. The study comprised questionnaires directed at the whole study population and subsequent personal interviews with adolescents found to be screen-positive for eating disorders, at both baseline and three-year follow-up. Results: The lifetime prevalence rates for 18 year old females were 2.6 % for anorexia nervosa, 0.4 for bulimia nervosa, and 9.0 % for eating disorder not otherwise specified (EDNOS). No prevalent case of DSM-IV eating disorders was found among the male participants. Eating disorders, as well as depressive symptoms, social anxiety, and low self-esteem, was more prevalent among females who perceived themselves as being overweight, despite being normal or underweight, when compared to females with a correct weight perception. An incorrect weight perception was associated in males with social anxiety. Female adolescents dieting due to psychological distress, rather than vanity or overweight, had a fifteen-fold risk of developing an eating disorder. Conclusions: Eating disorders are common among female adolescents, and adolescents choosing to diet due to psychological distress show a markedly increased risk of developing an eating disorder. Promotion of general well-being as well as the prevention of body dissatisfaction and misdirected dieting, accompanied by early detection and proper treatment of eating disorders, is needed to reduce the incidence of and facilitate recovery in adolescents suffering from eating disorders.

Health-related quality of life in school children: validation of instrument, child self assessment, parent-proxy assessment and school nursing documentation of health check-ups

The aims of this study were to validate an international Health-Related Quality of Life (HRQL) instrument, to describe child self and parent-proxy assessed HRQL at child age 10 to 12 and to compare child self assessments with parent-proxy assessments and school nursing documentation. The study is part of the Schools on the Move –research project. In phase one, a cross-cultural translation and validation process was performed to develop a Finnish version of Pediatric Quality of Life Inventory™ 4.0 (PedsQL™ 4.0). The process included a two-way translation, cognitive interviews (children n=7, parents n=5) and a survey (children n=1097, parents n=999). In phase two, baseline and follow-up surveys (children n=986, parents n=710) were conducted to describe and compare the child self and parent-proxy assessed HRQL in school children between the ages 10 and 12. Phase three included two separate data, school nurse documented patient records (children n=270) and a survey (children n=986). The relation between child self assessed HRQL and school nursing documentation was evaluated. Validity and reliability of the Finnish version of PedsQL™ 4.0 was good (Child Self Report α=0.91, Parent-Proxy Report α=0.88). Children reported lower HRQL scores at the emotional (mean 76/80) than the physical (mean 85/89) health domains and significantly lower scores at the age of 10 than 12 (dMean=4, p=<0.001). Agreement between child self and parent-proxy assessment was fragile (r=0,4, p=<0.001) but increased as the child grew from age 10 to 12 years. At health check-ups, school nurses documented frequently children’s physical health, such as growth (97%) and posture (98/99%) but seldom emotional issues, such as mood (2/7%). The PedsQLTM 4.0 is a valid instrument to assess HRQL in Finnish school children although future research is recommended. Children’s emotional wellbeing needs future attention. HRQL scores increase during ages between childhood and adolescence. Concordance between child self and parent-proxy assessed HRQL is low. School nursing documentation, related to child health check-ups, is not in line with child self assessed HRQL and emotional issues need more attention.

Effect of cocaine on periadolescent rats with or without early maternal separation

Cocaine-induced behavioral sensitization and weight loss were investigated in periadolescent Wistar rats kept with their mothers or subjected to repeated maternal separation. Litters allocated to the separation procedure were placed in a temperature-controlled (33ºC) chamber for 3 h per day from postnatal day 6 (P6) to P20. Non-handled rats were left undisturbed until weaning. Treatments were started on P30-31 and the test was performed on P36-37. Animals received injections of saline or cocaine (10 mg/kg, sc) twice daily for 5 days. On day 6 all animals received saline. On day 7 animals were challenged with 10 mg/kg cocaine and their locomotion was evaluated in activity cages. A third group received saline throughout the 7-day period. Body weights were recorded on P30-31 and P36-37. Two-way ANOVA on body weights showed a main effect of treatment group (F(1,35) = 10.446, P = 0.003; N = 10-12). Non-handled rats treated with cocaine for 5 days gained significantly less weight, while no significant effect was observed in maternally separated rats. Two-way ANOVA revealed a main effect of drug treatment on locomotor activity (F(2,32) = 15.209, P<0.001; N = 6-8), but not on rearing condition (F(1,32)<0.001, P = 0.998). Animals pretreated with cocaine showed a clear behavioral sensitization relative to the saline group. No difference in the magnitude of sensitization was found between separated and non-handled animals. Only the effect of cocaine on weight gain was significantly affected by repeated episodes of early maternal separation during the pre-weaning period.

Behavioral characteristics of the offspring of adolescent rats

The aim of this study was to test the hypothesis that, during adulthood, the offspring of adolescent rats differ in emotionality, learning and memory from the offspring of adult rats. The behavior of the offspring of adolescent (age, 50-55 days) and adult rats (age, 90-95 days) was tested in the open field, activity cage, and passive and active avoidance apparatus. The latencies during training and testing in the passive avoidance apparatus of the offspring of adolescent parents were shorter than the latencies of control offspring (P<0.001 on both training and testing days). Offspring of adolescent parents showed shorter latency time in acquisition trials during active avoidance testing compared to control offspring (P<0.001). They also showed a higher number of active avoidance responses in the last four blocks of acquisition (P<0.001) and first two blocks of extinction trials (P<0.05 and P<0.001, respectively). The offspring of adolescent parents showed higher latency on the first day of testing in the open field (P<0.01) and a lower latency on the third day of testing (P<0.01). They also showed higher activity during all three days of testing (1st and 2nd day: P<0.01; 3rd day: P<0.05). The spontaneous activity of the offspring of adolescent parents in the activity cage was higher in the last three intervals of testing (P<0.001). In summary, the offspring of adolescent parents were less anxious and tended to be more active. The results of two learning and memory tests were opposite, but could be explained by a higher exploratory drive of the offspring of adolescent parents. This was probably due to chronic malnutrition stress and the disturbed mother-infant relationship in the litters of adolescent mothers.

Gender-related pathways for behavior problems in the offspring of alcoholic fathers

The objective of the present study was to examine gender differences in the influence of paternal alcoholism on children's social-emotional development and to determine whether paternal alcoholism is associated with a greater number of externalizing symptoms in the male offspring. From the Mannheim Study of Risk Children, an ongoing longitudinal study of a high-risk population, the developmental data of 219 children [193 (95 boys and 98 girls) of non-alcoholic fathers, non-COAs, and 26 (14 boys, 12 girls) of alcoholic fathers, COAs] were analyzed from birth to the age of 11 years. Paternal alcoholism was defined according to the ICD-10 categories of alcohol dependence and harmful use. Socio-demographic data, cognitive development, number and severity of behavior problems, and gender-related differences in the rates of externalizing and internalizing symptoms were assessed using standardized instruments (IQ tests, Child Behavior Checklist questionnaire and diagnostic interviews). The general linear model analysis revealed a significant overall effect of paternal alcoholism on the number of child psychiatric problems (F = 21.872, d.f. = 1.217, P < 0.001). Beginning at age 2, significantly higher numbers of externalizing symptoms were observed among COAs. In female COAs, a pattern similar to that of the male COAs emerged, with the predominance of delinquent and aggressive behavior. Unlike male COAs, females showed an increase of internalizing symptoms up to age 11 years. Of these, somatic complaints revealed the strongest discriminating effect in 11-year-old females. Children of alcoholic fathers are at high risk for psychopathology. Gender-related differences seem to exist and may contribute to different phenotypes during development from early childhood to adolescence.

Influence of gender on psychomotor vigilance task performance by adolescents

During adolescence, the sleep phase delay associated with early school times increases daytime sleepiness and reduces psychomotor performance. Some studies have shown an effect of gender on psychomotor performance in adults and children. Males present faster reaction times (RT) compared with females. The aim of the present study was to evaluate the influence of gender on Palm psychomotor vigilance task (PVT) performance in adolescents. Thirty-four adolescents (19 girls, 13 to 16 years old) attending morning school classes of a public school in Curitiba, PR, Brazil, participated in the study. Sleep patterns were measured using actigraphy and sleepiness data were accessed with the Karolinska Sleepiness Scale (KSS). KSS and PVT measurements were collected at two times in the morning (8:00 and 11:00 h). The data were compared using one-way ANOVA, considering gender as a factor. ANOVA indicated that gender did not affect sleep patterns and subjective somnolence; however, a statistically significant effect of gender was detected for PVT performance. Boys presented faster RT (RT-PVT1: 345.51 ms, F = 6.08, P < 0.05; RT-PVT2: 343.30 ms, F = 6.35, P < 0.05) and fewer lapses (lapses-PVT1: 8.71, F = 4.45, P < 0.05; lapses-PVT2: 7.82, F = 7.06, P < 0.05) compared with girls (RT-PVT1: 402.96; RT-PVT2: 415.70; lapses-PVT1: 16.33; lapses-PVT2: 17.80). These results showed that this effect of gender, already reported in adults and children, is also observed in adolescents. The influence of gender should be taken into account in studies that use Palm PVT to evaluate psychomotor performance in this age range.

Repeated exposure of adolescent rats to oral methylphenidate does not induce behavioral sensitization or cross-sensitization to nicotine

Several lines of evidence indicate that the use of stimulant drugs, including methylphenidate (MPD), increases tobacco smoking. This has raised concerns that MPD use during adolescence could facilitate nicotine abuse. Preclinical studies have shown that repeated treatment with an addictive drug produces sensitization to that drug and usually cross-sensitization to other drugs. Behavioral sensitization has been implicated in the development of drug addiction. We examined whether repeated oral MPD administration during adolescence could induce behavioral sensitization to MPD and long-lasting cross-sensitization to nicotine. Adolescent male Wistar rats were treated orally with 10 mg/kg MPD or saline (SAL) from postnatal day (PND) 27 to 33. To evaluate behavioral sensitization to MPD in adolescent rats (PND 39), the SAL pretreated group was subdivided into two groups that received intragastric SAL (1.0 mL/kg) or MPD (10 mg/kg); MPD pretreated rats received MPD (10 mg/kg). Cross-sensitization was evaluated on PND 39 or PND 70 (adulthood). To this end, SAL- and MPD-pretreated groups received subcutaneous injections of SAL (1.0 mL/kg) or nicotine (0.4 mg/kg). All groups had 8 animals. Immediately after injections, locomotor activity was determined. The locomotor response to MPD challenge of MPD-pretreated rats was not significantly different from that of the SAL-pretreated group. Moreover, the locomotor response of MPD-pretreated rats to nicotine challenge was not significantly different from that of the SAL-pretreated group. This lack of sensitization and cross-sensitization suggests that MPD treatment during adolescence does not induce short- or long-term neuroadaptation in rats that could increase sensitivity to MPD or nicotine.

Effects of simultaneous exposure to stress and nicotine on nicotine-induced locomotor activation in adolescent and adult rats

Preclinical studies have shown that repeated stress experiences can result in an increase in the locomotor response to the subsequent administration of drugs of abuse, a phenomenon that has been termed behavioral cross-sensitization. Behavioral sensitization reflects neuroadaptive processes associated with drug addiction and drug-induced psychosis. Although cross-sensitization between stress- and drug-induced locomotor activity has been clearly demonstrated in adult rats, few studies have evaluated this phenomenon in adolescent rats. In the present study, we determined if the simultaneous exposure to stress and nicotine was capable of inducing behavioral sensitization to nicotine in adolescent and adult rats. To this end, adolescent (postnatal day (P) 28-37) and adult (P60-67) rats received nicotine (0.4 mg/kg, sc) or saline (0.9% NaCl, sc) and were immediately subjected to restraint stress for 2 h once a day for 7 days. The control group for stress was undisturbed following nicotine or saline injections. Three days after the last exposure to stress and nicotine, rats were challenged with a single dose of nicotine (0.4 mg/kg, sc) or saline and nicotine-induced locomotion was then recorded for 30 min. In adolescent rats, nicotine caused behavioral sensitization only in animals that were simultaneously exposed to stress, while in adult rats nicotine promoted sensitization independently of stress exposure. These findings demonstrate that adolescent rats are more vulnerable to the effects of stress on behavioral sensitization to nicotine than adult rats.

Animal models of prenatal immune challenge and their contribution to the study of schizophrenia: a systematic review

Prenatal immune challenge (PIC) in pregnant rodents produces offspring with abnormalities in behavior, histology, and gene expression that are reminiscent of schizophrenia and autism. Based on this, the goal of this article was to review the main contributions of PIC models, especially the one using the viral-mimetic particle polyriboinosinic-polyribocytidylic acid (poly-I:C), to the understanding of the etiology, biological basis and treatment of schizophrenia. This systematic review consisted of a search of available web databases (PubMed, SciELO, LILACS, PsycINFO, and ISI Web of Knowledge) for original studies published in the last 10 years (May 2001 to October 2011) concerning animal models of PIC, focusing on those using poly-I:C. The results showed that the PIC model with poly-I:C is able to mimic the prodrome and both the positive and negative/cognitive dimensions of schizophrenia, depending on the specific gestation time window of the immune challenge. The model resembles the neurobiology and etiology of schizophrenia and has good predictive value. In conclusion, this model is a robust tool for the identification of novel molecular targets during prenatal life, adolescence and adulthood that might contribute to the development of preventive and/or treatment strategies (targeting specific symptoms, i.e., positive or negative/cognitive) for this devastating mental disorder, also presenting biosafety as compared to viral infection models. One limitation of this model is the incapacity to model the full spectrum of immune responses normally induced by viral exposure.

The role of self-presentation in adolescent health risk behaviours

Self-presentation has been identified as playing a key role in the perfonnance of various potentially hazardous health behaviours such as substance abuse, eating disorders and reckless behaviours (Leary, Tchividjian, & Kraxberger, 1994; Martin & Leary, 2001; Martin, Leary, & O'Brien, 2001). The present study investigated the role of selfpresentation on adolescent health-risk behaviours. Specifically, this study examined the prevalence of adolescent identified health-risk behaviours rooted in self-presentational motives in youths aged 13-18 years. The current study also identified the specific images associated with these behaviours desired by youth, and the targets of these behaviours. Also, the relationship between these behaviours, and several trait measures (social physique anxiety, public-self consciousness, fear of negative evaluations, selfpresentational efficacy) of self-presentation were examined. Finally, the gender differences in health risk behaviours and self-presentational concerns were examined. Participants in the present study were 96 adolescent students, 34 male and 62 female, recruited from various private schools across Southern Ontario. Students ranged in age from 13 to 18 years for both males (M age = 15.81 years, SD = 1.49) and females (M age = 14.89 years, SD = 1.17) and ranged from grades 8 through 13. Results of the current study suggested that Canadian adolescents between the ages of 13 and 18 years participated in health risk behaviours for self-presentational purposes. Drinking alcohol, skipping school, and performing stunts and dares were identified as the most common health risk behaviours performed for self-presentational purposes by both males and females. Appearing fun and cool were the most commonly reported desired images while appearing brave and mature were the least reported. The most desired target group cited was same sex friends, followed by other sex friends. Trait measures of self-presentational concerns identified females as being higher in public self-consciousness, and social physique anxiety than males. Males were found to be higher in self-presentational efficacy than females. The total number of health risk behaviours was predicted by selfpresentational efficacy and social physique anxiety for males, and social physique anxiety for females. Findings of the current study suggest that Canadian adolescents' health risk behaviours are rooted, in part, in self-presentational motives. Thus far, an educational approach to health interventions has been favoured and/or adopted by teachers, health promoters, and educators (Jessor, 1992). Implications of the current study suggest that although educational interventions are beneficial in presenting the associated risks with certain activities and/or behaviours, one reason this type of approach may be ineffective in changing adolescent behaviour over the long run is that it does not address the strong and prominent influences of interpersonal motives on health damaging behaviour. It is evident that social acceptance and public image are of importance to adolescents, and the desire to make the "right" impression and to achieve peer approval and acceptance often override health and safety concerns (Jessor, 1992). Thus, a self-presentational approach focusing on changing the images associated with the behaviours may be more successful at deterring adolescent health risk behaviours.

An investigation of adolescent constructs of stress and academic achievement /

The present study was a phenomenological investigation of adolescent constructs of stress and academic achievement. The study utilised a modified version of George Kelly's Repertory Grid Technique to provide direct insight into adolescent stress and academic achievement. The premise of the study was that only students who exhibited extreme cases of stress and academic achievement levels would be examined. The investigation identified and examined the adolescents who exhibited these extremes and explored the underlying constructs that defined these differences. It was expected that if adolescents were able to identify the stressors in their lives, how these stressors affect their lives, and how these stressors affect their academic performance, then suggestions could be made to help students to better cope with stress and to improve their academic achievement level. Further, based on the results of the study, the pedagogical implications for classroom research are provided. Phenomenological inquiries, using modified, and less complex versions of the repertory grid, can be conducted pre-, mid-, and postacademic terms, to determine and to monitor the stressors and the academic performance of the students in a classroom. Specific assessments for individual students will help teachers to better exercise their knowledge and understanding of the realm of teaching and learning strategies (e.g., Gardiner's Multiple Intelligences) that exist.

Menstrual status and thermoregulatory responses of active adolescents during exercise in a cold environment

This study examined the interactions between the reproductive status and the thermoregulatory responses during exercise in the cold in girls involved in competitive sports. Four girls with established menstrual cycles comprised the eumenorrheic menarcheal group (EM) and 5 non-menstruating girls comprised the pre-menarcheal group (PM). During the first visit maximal oxygen consumption, height, weight and percent body fat (%BF) were measured. The second visit involved: a determination of metabolic rate in thermoneutrality (21°C) involving 10-min rest and 20-min cycling (30% of VCL max), and a cold stress test (5°C, 40% humidity, <0.3 m/s air velocity) involving 20-min rest and 40-min cycling (30% of VCL max.). Subjects in the EM group were tested twice in the chamber during the follicular and luteal phases. Pre-menarcheal subjects were found to have significantly (p<0.05) lower core temperatures during the final stages of cold exposure. Overall, body fat was not significantly correlated with core temperature in the cold, however there was a significant surface-to-mass ratio difference between the groups. While in the follicular phase, EM girls had a higher core temperature during cold exposure. Therefore, reproductive hormonal status seems to be an important factor in terms of cold tolerance in females during adolescence.

The nature of bullying among secondary school students /

The purpose of this research was to determine the prevalence and effect of bullying in a secondary school. Six hundred and fifty-nine student volunteers completed a survey which included a quantitative component of 40 questions and 3 questions which required a written response. The results suggest that approximately 1 student in 10 was involved in a bullying situation either as a bully or a victim. As age increased, physical bullying decreased whereas psychological remained high in the senior years of high school. Boys were involved more in bullying than girls, especially in the junior years. The effects of bullying could be devastating to the point of school avoidance or early school leaving. The results also indicate that much of the bullying was not being reported. The implication for the education system is that more needs to be done to prevent bullying, to encourage the reporting of bullying, and to deal with the aftermath of a bullying situation.

What nourishes the spirit of adolescents in the classroom? : a qualitative study into the gateways of adolescents' souls /

This thesis investigated the question, "What nourishes the adolescent spirit in the classroom?" Action research was conducted by the teacher of 16 grade 8 participants. By undergoing Kessler's (2000) "Passages Program," the students participated in 6 sessions which exposed them to a holistic intrapersonal curriculum. Student journal responses were documented after each session. The action researcher also kept journal reflections after each session. Upon completion of the 6 sessions, a postinterview was conducted which posed the research question. The research found that the adolescent spirit gets nourished through encouragement by the teacher, peers, and parents. This increases their competency, which increases their confidence, and ultimately their self-esteem goes up, which affects their selfconcept. In addition, the role of the teacher permeates every aspect of what nourishes the adolescent spirit in the classroom. In addition to the encouragement of the student, how a teacher teaches plays a vital role. A holistic approach to teaching provided the best atmosphere for the adolescent. It promoted creativity and choice, which stimulated the spirit of the adolescent. By working from a holistic philosophy, the teacher/action researcher created an environment conducive to teaching the whole person, which ultimately nourished the participants' spirit. The research highlighted that in order for this type of environment to exist the teacher needs to make a conscious and deliberate effort to look within and develop their inner self before they can begin to promote this type of classroom for the adolescents they teach. When teachers and students develop an inner life together, they can begin to work in harmony to achieve an atmosphere where the teaching and learning environment becomes one seamless transaction. Only then can one's whole potential be realized.