Non-suicidal self-injury (NSSI), such as intentionally cutting, burning or hitting oneself, is a behavior with potentially detrimental consequences and empirical studies are necessary to gain knowledge of how to prevent NSSI in adolescents. The aims of this thesis were to investigate the prevalence, methods, characteristics and functions of NSSI in a large community sample of Swedish adolescents, and to examine the relationship between NSSI and adverse life events and trauma symptoms. All empirical studies had a cross-sectional design and were based on 3,097 adolescents in the county of Östergötland, aged 15-17 years, in their first year of high school. Participating school classes were selected through a randomization process and administered self-report questionnaires. In study I (n = 3,060) a single item NSSI question resulted in a prevalence rate of 17.2%, while 35.6% of adolescents reported having engaged in NSSI at least once during the past year when given a checklist. The most commonly reported type of NSSI in this sample was “bit yourself”, followed by “hit yourself on purpose”, “erased your skin” and “cut or carved on your skin”. Applying the proposed DSM-5 diagnostic criteria of NSSI resulted in a prevalence rate of 6.7%. Results in study II (n = 2,964) showed that after controlling for gender, parental occupation and living conditions, adolescents with no self-injurious behavior reported the lowest level of adversities and trauma symptoms, while adolescents with both NSSI and suicide attempts (5.7%) reported the highest levels compared to those with only NSSI or a suicide attempt. Adolescents reporting frequent NSSI reported more adversities and trauma symptoms than those with less frequent NSSI. Automatic functions, such as affect regulation, self-punishment and feeling-generation, were the most commonly reported functions of NSSI. Attempts in study I to confirm Nock and Prinstein’s (2004) four-factor model of underlying factors of NSSI functions resulted in a close to acceptable fit. An attempt to refine the factor analysis on this community sample of Swedish adolescents, using Mplus with cross-validation, was made in study III (n = 836). An exploratory factor analysis resulted in a three-factor model (social influence, automatic functions and non-conformist peer identification), which was validated in confirmatory analysis. In order to adhere more closely to learning theory and the concept of negative and positive reinforcement, the third factor was then split into two factors, resulting in a four-factor model (social influence, automatic functions, peer identification and avoiding demands), which showed excellent fit to the data in the confirmatory factor analysis. Study IV (n = 816) showed that NSSI frequency, gender (female), self-reported experience of emotional and physical abuse, having made a suicide attempt, prolonged illness or handicap and symptoms of depression and dissociation were significant predictors in the final model of the automatic functions, indicating that these variables are important in understanding the mechanisms underlying the need to engage in NSSI to regulate emotions, generate feelings, gain control or to self-punish. Symptoms of depression and dissociation mediated the relationship between sexual, physical and emotional abuse and the automatic  functions. Furthermore, frequency of NSSI, gender, emotional abuse, prolonged illness or handicap and symptoms of depression uniquely predicted automatic functions but not social functions. Self-reported experience of physical abuse, having made a suicide attempt, symptoms of anxiety and dissociation were significant in the final model of social functions, i.e., performing NSSI to influence or  communicate with others, to avoid demands or to identify with peers. Of these, symptoms of anxiety were uniquely associated with social functions. Symptoms of anxiety and dissociation mediated the relationship between physical abuse and social functions of NSSI. Taken together, this thesis has shown that NSSI is prevalent in Swedish adolescents and findings contribute to the discussion of a potential NSSI diagnosis. It is important to consider the effect of different types of negative life events and trauma symptoms in relation to NSSI in adolescents. Assessing the specific reinforcing functions of NSSI and the underlying factor structure can be helpful in developing functionally relevant individualized treatment. / Självskadebeteende, t ex att avsiktligt skära, bränna eller slå sig själv är potentiellt skadliga beteenden. Empiriska studier är viktiga för att kunna förebygga självskadebeteende hos ungdomar. Föreliggande avhandling syftar till att undersöka självskadebeteendets förekomst, funktion, karaktäristik och metoder hos svenska ungdomar, samt att undersöka relationen till negativa livshändelser och traumasymptom. Samtliga fyra empiriska studier hade en tvärsnittsdesign och baserades på 3,097 ungdomar i Östergötland, 15-17 år, i gymnasieskolans årskurs 1, vars skolklasser valts ut slumpmässigt och som besvarat självskattningsformulär. I studie I (n = 3,060) angav 17.2%, som svar på en allmän självskadefråga, att de avsiktligt skadat sig under sin livstid. När ungdomarna däremot svarade på en checklista med olika självskadebeteenden, angav 35.6% att de hade ägnat sig åt någon typ av självskadebeteende under det senaste året. De vanligaste metoderna var att avsiktligt bita eller slå sig själv, sudda på huden och att skära sig. De föreslagna diagnoskriterierna för icke-suicidal självskada i DSM-5 resulterade i en förekomst av 6.7%. Studie II (n = 2,964) visade att ungdomar utan självskadebeteende rapporterade de lägsta antalet negativa livshändelser och traumasymptom, medan de med erfarenhet av både självskadebeteende och självmordsförsök (5.7%) rapporterade de högsta antalen jämfört med de med endast självskadebeteende eller självmordsförsök. Ungdomar med fler självskadetillfällen rapporterade fler negativa livshändelser och traumasymptom än de med färre tillfällen. Automatiska/intrapersonella funktioner, såsom att generera och reglera känslor samt att straffa sig själv var de vanligaste funktionerna som rapporterades. Försök att konfirmera Nock och Prinsteins (2004) fyrfaktormodell av underliggande funktionsfaktorer i studie I resulterade i en modell med nära acceptabel passform. Ett försök att förbättra faktoranalysen på den aktuella urvalsgruppen gjordes med Mplus i studie III (n = 836). En exploratorisk analys resulterade i en trefaktormodell (interpersonell påverkan, automatisk/intrapersonell funktion samt ”icke-konformistisk” kamratidentifikation), vilken även validerades i den konfirmatoriska analysen. Med utgångspunkt i inlärningsteori och begreppen negativ och positiv förstärkning delades därefter den tredje faktorn upp i två faktorer. Det resulterade i en fyrfaktormodell (interpersonell påverkan, automatisk/intrapersonell funktion, kamratidentifikation samt undvikande av krav). Fyrfaktormodellen visade utmärkt passform i den konfirmatoriska analysen. Studie IV (n = 816) visade att självskadebeteendets frekvens, kön (flicka), självrapporterade erfarenheter av psykisk och fysisk misshandel, självmordsförsök, kronisk sjukdom eller handikapp under uppväxten, liksom symptom på depression och dissociation predicerade automatiska självskadefunktioner. De variablerna är potentiellt viktiga för förståelsen av de mekanismer som är involverade när ungdomar skadar sig själva för att generera och reglera känslor, få kontroll, liksom att straffa sig själva. Relationen mellan psykisk och fysisk misshandel och de automatiska funktionerna medierades av symptom på depression och dissociation. Självskadefrekvens, kön, psykisk misshandel, sjukdom/handikapp och symptom på depression predicerade enbart automatiska men inte sociala funktioner. Självrapporterad fysisk misshandel, självmordsförsök, symptom på ångest och dissociation var signifikanta prediktorer för de sociala funktionerna (att påverka/kommunicera med andra, undvika krav eller identifiera sig med kamrater). Ångestsymptom var unikt associerade med sociala funktioner. Symptom på ångest och dissociation medierade vidare relationen mellan fysisk misshandel och sociala självskadefunktioner. Sammanfattningsvis visade resultaten att självskadebeteende är vanligt förekommande hos ungdomar. Avhandlingen bidrar med empiri till diskussionen gällande icke suicidal självskada i DSM-5. Det är viktigt att beakta olika negativa livserfarenheter och traumasymptom i relation till självskadebeteende hos ungdomar. Att undersöka självskadebeteendets funktioner kan vara kliniskt hjälpsamt för att utveckla och utvärdera individuellt anpassade behandlingsstrategier.

Cultural socialization of adolescents’ ethnic identity is associated with the context surrounding adolescents and their families. Cross-sectional data collected from Canadian immigrant Chinese families (N = 183) were used to investigate the role of parents in adolescents’ ethnic identity development. Study 1 examined direct and moderated relations (i.e., adolescents’ gender, age, and parents’ perceptions of discrimination) between parents’ ethnic identity and cultural orientation goals for their adolescents and parental enculturation efforts. Study 2 examined direct and moderated relations (i.e., adolescents’ gender, age, parental warmth, presence of grandparents and adolescents’ reports of discrimination) among parental enculturation and the number of Chinese friends, and adolescents’ ethnic identity (both ethnic identity achievement and ethnic affirmation and belonging). Study 1 results showed that parents’ ethnic identity and Chinese and Canadian cultural orientation goals for their adolescents were directly associated with their enculturation efforts. Fathers’ reports of discrimination moderated the relations between his Chinese cultural orientation goals for his adolescent and his enculturation efforts. Specifically, this relationship was particularly strong among fathers who reported lower levels of discrimination. These findings suggest that immigrant Chinese parents’ decision to engage in enculturation may be intrinsically motivated. Study 2 results showed that parental enculturation, maternal warmth, and adolescents’ reports of discrimination contributed to adolescents’ ethnic identity achievement. These results suggest that adolescents’ ethnic identity achievement may be supported by opportunities for adolescents to learn about their ethnic culture through parental enculturation and think about their ethnicity through experiences of discrimination. In comparison, adolescents’ feelings of ethnic affirmation and belonging were related to mother-father enculturation differences, the number of Chinese friends, and maternal warmth. These findings suggest that feelings of ethnic affirmation and belonging for adolescents may be supported by flexibility related to mothers and fathers engaging in differing levels of enculturation, and autonomy related to adolescents having more Chinese friends. Adolescents’ age moderated the relations between fathers’ enculturation efforts and adolescents’ ethnic identity achievement. The few moderated findings further underscored the importance of parents in Chinese adolescents’ ethnic identity development. / Graduate

The present study involved an extension and evaluation of a mindfulness-based training program for families of adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD). MYmind: Mindfulness training for Youth with ADHD and their parents (Bogels et al., 2008) is an eight-week manualized treatment incorporating elements of mindfulness meditation, ADHD psychoeducation and cognitive behavioural therapy. MYmind focuses on helping families cultivate mindfulness through training in formal meditation practices and integrating this skill into the context of everyday life as a means of managing ADHD symptoms, stress, family relations and difficult emotions. A North American sample of 13 parents and 9 adolescents (ages 13-18) participated in MYmind; during the intervention, parents and adolescents attended separate groups that ran simultaneously. Using a time-series multiple baseline design, constructs of stress, distress from family conflict, ADHD symptomatology and meditation practice were measured via short questionnaires emailed daily to both parents and adolescents throughout baseline, treatment and six months of follow-up. For multiple baseline purposes, intervention was introduced in a time-lagged fashion. Results from parent and adolescent reports indicated reductions in parent and adolescent stress, parent and adolescent distress due to family conflict, and increased frequency and duration of meditation practice. Parent reports suggested a decrease in their adolescents’ inattention, hyperactivity and impulsivity symptoms after participating in MYmind, a reduction that was not confirmed by adolescent reports. Most treatment gains were maintained up to six-months following treatment completion. Meditation practice was significantly correlated with reduced stress levels for both groups. Both parents and adolescents reported high satisfaction with the MYmind program overall. Mindfulness training appears to hold considerable potential for improving the multiple difficulties experienced by adolescents with ADHD and their parents.

In this study, a user-centred design approach was used to develop a mobile health application designed to support adult T1DM patients with their self-management routine. In the requirements gathering phase, an observational study of a diabetes clinic and patient interviews were conducted. An analysis of the data collected from this phase helped identify the functional design requirements used to guide the design. Using a rapid prototyping approach, data visualizations, game-based elements, carb-counting and social networking features were explored. The final prototype developed in this research was evaluated for its ease of use and perceived usefulness. The design was found to be generally easy to use. With respect to data visualizations, participants preferred the scatter plot view of their blood glucose readings to a bar chart. In addition, it was found that all participants wanted a way to track their HbA1c on a regular basis.

Background: South Asian girls have reported low levels of physical activity (PA) compared to other Canadian adolescents. Potential explanations include omissions in existing PA measures that don’t capture all types of PA, and factors discouraging PA in this group. Purpose: This study examined the quality and quantity of PA; compared PA participation using two self-report methods; and, examined psychosocial and cultural factors associated with PA in adolescent South Asian girls. Methods: 113 participants were recruited from community sources in Toronto. Data were collected using a structured electronic diary (3 weekdays; 2 weekend days) and a self-administered online questionnaire that included the Leisure Time Exercise questionnaire. Diaries were content analyzed and compared to PA reports in the questionnaire. Bivariate and multivariate regression analyses identified factors associated with PA. Results: Diaries revealed that when a range of PA types were captured, like walking activities and chores, PA levels were similar to representative data for Canadian youth. 92% of respondents reported at least 30 minutes of PA per day across their diary entries. However, 19% did not report any PA at the vigorous intensity level, and PA levels were lowest on weekends. Reports of PA in the diary and questionnaire were inconsistent, with considerably higher levels of PA reported in the questionnaire. Enrolment in physical education, enjoyment, control, fewer barriers, and social provisions were associated with greater PA. Conclusions: Physical activity levels were low, but results did not suggest that South Asian girls are more vulnerable to low levels of activity compared to other Canadian girls. Findings from the diary suggest that PA questionnaires would benefit from including a broader range of activity types with a variety of walking activities, and structured reflections to enhance data quality and minimize the potential for over-reporting. PA levels may be increased through mandatory physical education, curricula that emphasize how girls may engage in vigorous activities outside of classes, and changes to neighbourhood environments that would promote walking.

La present investigació es va dur a terme al centre Can Rubió d'Esparreguera (BCN). HIPÒTESI: el Programa de Teràpia Institucional (PTI) que se segueix al centre opera algunes modificacions en el funcionament psíquic i relacional dels adolescents que el segueixen.OBJECTIUS: avaluar els canvis que produeix el PTI en l'organització de la personalitat, en el funcionament relacional, en les estratègies d'afrontament de problemes i en els recursos cognitius, i, en segon lloc, cercar la possible relació d'aquests canvis amb algunes circumstàncies dels subjectes (adolescents en situació de desemparament i amb trastorns psíquics greus).PROCEDIMENT: s'han practicat tres avaluacions: moment inicial, curt termini (8 mesos) i mitjà termini (15 mesos). Les puntuacions obtingudes en el moment inicial s'han comparat amb els barems dels respectius tests (barem per a adolescents italians en el cas del Rorschach).Les puntuacions obtingudes a curt i mitjà terminis s'han comparat amb les puntuacions obtingudes en el moment inicial, calculant la significació estadística de les diferències (T de Wilcoxon) i la significació clínica (mètode de Cohen) de les diferències, prenent com a criteri de significació clínica un ES>0,37 (Lipsey).S'han calculat les tendències (regressions lineals, mètode de mínims quadrats) per a una selecció de 17 índexs i la relació (Spearman) d'aquestes tendències amb algunes circumstàncies dels subjectes.INSTRUMENTS: test de Rorschach, YSR,CRI i els subtests de Vocabulari, Semblances i Cubs del WISC-R.SUBJECTES: 31 en el moment inicial, 25 i 19 a curt i mitjà terminis, respectivament, d'ambdós sexes, amb diversos tipus de patologia psíquica.RESULTATS: en el moment inicial: els subjectes presenten nombrosos problemes emocionals i de conducta, predomini de l'ús d' estratègies d'evitació en l'afrontament de problemes, tendència a la dissociació i/o actuació, fallades en la percepció interna i externa, escassos recursos ideacionals i emocionals, nombrosos trastorns del curs i del contingut del pensament, manca d'interès en els altres, passivitat i dependència de l'entorn, i dificultats per percebre la convencionalitat social i les normes del grup.A curt termini: s'observen molt pocs canvisA mitjà termini: s'observen millores en el control i la tolerància a l'estrès, l'autopercepció., la identificació social, la internalització, l'externalització i en l'ús de les estratègies d'aproximació als conflictes, disminució dels trastorns del pensament. S'incrementen la tendència a la passivitat ideacional, la dependència de l'entorn i l'ús de l'evitació com a estratègia d'afrontament. La tendència a la millora presenta una correlació significativa negativa amb el nombre d'ingressos psiquiàtrics i la seva duració. La tendència a l'immobilisme psíquic presenta una correlació significativa negativa amb el suport familiar. DISCUSSIÓ: la discreció dels resultats pot ser deguda a la presència de molts factors relacionats amb l'abandonament, la carència i la situació familiar dels subjectes i a l'absència de patiment psíquic/raons per canviar, d'introspecció i de confiança en els altres.CONCLUSIONS: la implantació d'un model multimodal és factible i proporciona informació vàlida per a l'anàlisi de l'evolució clínica individual, per a intercanviar-la amb altres professionals, com a indicador de la qualitat del Servei i genera una base de dades estandarditzades que possibilita la investigació. Aquest PTI no està indicat per a subjectes que han fets nombrosos i/o llargs ingressos psiquiàtrics. L'edat, la psicopatologia, la situació familiar, la comorbilitat i les perspectives de futur configuren unes organitzacions de la personalitat cristal·litzades i molt difícils de modificar. L'increment de la passivitat ideacional, de la dependència de l'entorn i de l'evitació com a estratègia d'afrontament requereixen que s'identifiquin els elements del propi PTI, de la quotidianitat i de la normativa que regeix el centre que poden contribuir a l'increment d'aquests factors i introduir les modificacions pertinents en cada un d'aquests tres àmbits. / OBJECTIVE: To evaluate the impact of an institutional therapy programme on adolescents' (aged between 12 and 18 years, both sexes) personality, relationships, and coping strategies suffering severe mental disorders and coming from broken families. PROCEDURE: Three evaluations were carried out. At income (n=31), after 8 (n=25) and 15 months (n=19). Participants were evaluated with the Rorschach test, YSR, CRI, and WISC-R. Income scores bring information about kind, degree, and variety of mental dysfunctions. Scores obtained after 8 and 15 months were compared with income ones in order to explore statistically (Wilcoxon) and clinically significant differences (Cohen; ES>0.37 Lipsey). A total of 17 indices were calculated (minimum least squares regression) and their correlation (Spearman) with some other variables of participants were explored. RESULTS. At income, severe dysfunctions were observed in domains such as emotions, thoughts, perception, behaviour, interpersonal relationships, coping styles, and social relationships.After 8 months under treatment, changes were minimum.After 15 months, stress control and tolerance, self-perception, social conventions, internalisation, externalisation, approach strategies, and thoughts improved. Additionally, ideational passivity, dependence on the environment, and avoidance as a coping strategy augmented.Improvement was negatively and significantly associated to psychiatric hospitalisations and their duration. Family support was negatively and significantly associated to psychic immobility. DISCUSSION: Variables such as abandonment, lack, family situation, sense of controlling everything, and therefore, absence of motivation to change and lack of insight and feelings of distrust could hinder treatment benefits and explain poor results. CONCLUSIONS: This programme is not recommended for subjects with many or long psychiatric inpatient stays. Age, psychopathology, family situation, comorbidity, and perspectives about the future conform some strong pathological personality features that could hardly change. The programme must be reviewed to identify and modify factors that could be contributing to augment passivity, avoidance, and dependence on the environment.

El hecho que desencadenó la secuencia de acontecimientos de los que este trabajo es el resultado final se remonta a 1992 cuando inicio los cursos de doctorado en el programa "Diferencias educativas e igualdad de oportunidades" del Departamento de Métodos de Investigación y Diagnóstico en Educación de la Facultad de Pedagogía de la Universidad de Barcelona. Además de introducirme en el ámbito de la Educación intercultural a través de los estudios de tercer ciclo, mi adscripción como colaboradora al equipo de investigación coordinado por la Dra. Bartolomé que, por entonces, había recibido una subvención del "Centro de Investigación, Documentación y Evaluación" del Ministerio de Educación y Ciencia para desarrollar un amplio proyecto de investigación relacionado con la presencia en las escuelas de un número, cada vez mayor, de niños y niñas procedentes de diversos grupos culturales, permitió que mi formación como alumna de doctorado se ampliara al ponerme en contacto directo con la realidad que día a día se vive en los centros educativos. Las situaciones vividas en dicho proyecto de investigación me llevaron a interesarme cada vez más por el tema del desarrollo de la identidad étnica en niños y adolescentes y, concretamente, cómo se configuraba, cambiaba, o reelaboraba la identidad del alumnado inmigrante al entrar en contacto con una cultura diferente a la propia. El trabajo que presentamos se organiza en dos partes: una primera parte, compuesta por cinco capítulos, que supone una contextualización y exploración teórico-conceptual del tema de estudio; y, una segunda, en la que se recogen, a lo largo de otros cinco capítulos, el diseño, planificación, puesta en práctica y evaluación de nuestra propuesta de intervención.

Health-Related Quality of Life (HRQOL) is an important outcomes measure in cancer and there are specific issues depending on the site, stage, treatment and patient age. Although numerous instruments are available for cancer HRQOL, most are designed for adults, some for children, but none for adolescents and young adults (AYA) who have special age-specific concerns and poor improvement in survival compared with other age groups. An existing HRQOL instrument was modified to ensure its suitability for AYA, its validity, reliability and sensitivity were tested in Australians aged 16 to 25 years old diagnosed with cancer or a blood disorder. Varni’s PedsQLTM Measurement Model (13-18 year olds) was selected, modified then administered to families recruited from haematology/oncology clinics and wards at three Sydney Metropolitan Hospitals in person or by telephone. The Memorial Symptom Assessment Scale was used to categorise participants into groups reflecting sensitivity of symptom severity (slight, moderate and severe). The instruments demonstrated excellent internal consistency reliability, making them suitable for both group and individual comparisons. Clinical validity, construct validity, and discriminant validity were demonstrated by “known-groups” analysis, exploratory factor analysis and correlations, respectively. These new versions of the PedsQL Generic Core and Cancer Module are reliable, valid and sensitive measures of HRQOL in patients aged 16-25 years diagnosed with cancer or a blood disorder. The measures will soon be available for use as outcome measures in clinical trials and clinical practice with this age cohort in Australasia and internationally.

Plasma lipid, lipoprotein and apolipoprotein levels are considered as important and well-established intermediate quantitative phenotypes of Cardiovascular Disease (CVD) risk. Both the mean values and the phenotypic variance vary over the human lifespan. However, it is not known whether there is a genetic basis for this age variability. For example, might different genes act, or different gene interactions occur, as a person ages? If so, how might this be influenced by both environment and phenotype? An understanding of traits at different ages will not only provide insight into the genetic components involved in CHD development, but may also identify additional genetic factors that predispose an individual or population to premature (and later-onset) CHD. By identifying genetic factors that account for variation in important intermediate traits (i.e. lipid levels), we hope to gain a better understanding of disease mechanisms and thus a better chance of developing clinical strategies for preventing or possibly treating abnormal lipid levels and, by association, CHD. The aim of this thesis was to better identify and explain the genetic basis of CHD by focusing on the use of lipid traits as intermediate quantitative phenotypes of CHD. First, phenotypic analyses using structural equation modeling were performed to estimate the relative importance of genetic and environmental factors, and also to investigate whether these traits are influenced by the same gene(s) across time or whether they are age-specific genetic effects. Then, genome-wide linkage analysis was performed to localize cardiovascular susceptibility loci. Finally, a small genome-wide association scan (GWAS) was performed on a subset of the data to identify the relevant variants, in particular those showing associations across time. Phenotypes and marker data were collected in two Australian samples: an adolescent and adult twin pair samples. The adult sample consisted of 1453 twin pairs (968 monozygotic and 485 dizygotic), measured for lipid traits. 415 adult twins provided blood on two to five occasions. The adolescent dataset consisted of 965 twin families (397 monozygotic and 568 dizygotic) measured longitudinally at ages twelve, fourteen and sixteen, and their siblings tested once for the same lipid variables. Results from both the adult and adolescent cohorts indicated that there is more than one genetic factor influencing total cholesterol, HDL, LDL and triglycerides over time (i.e. from different measurement occasions). Common environmental factors did not contribute to variances (except for HDL in adolescents). There were no sex differences in the heritabilities of these intermediate phenotypes. Non-shared environmental factors did not have significant long-term effects. Overall, these two cohorts confirmed that genetic variation contributes substantially to variation in these traits, and suggested there are changes in the genes affecting plasma lipid concentration at different periods of life. Thus, there are age-dependent gene effects influencing HDL, LDL, total cholesterol, or triglycerides at different ages. In the adult genome data, there were 485 adult dizygotic twin pairs typed on average 595 markers, at an average inter-marker distance of 5.0 cM. The genome-wide linkage analysis revealed evidence for linkage in the 7p13 region for triglycerides. Possible candidate genes included NPC1L1 and GSBS. Other regions of “suggestive” linkage identified were chromosome 4p13 (at 62 cM) and Xq26.2-28 (81 cM). Adolescent twins and their siblings from 760 families were typed for linkage using 16,781 markers spaced across the genome at an average distance of 6.25 cM. The adolescent data revealed evidence for linkage to region 6p24.3 for triglycerides (–log10p = 6.81; equivalent LOD = 6.13; p = 0.00000016) and to region 2q31.1 for HDL (–log10p = 3.22, equivalent LOD = 2.27; p = 0.00061). No obvious candidate gene is known in this 6p region. Possible candidate genes in the 2q region include LRP2 and ABCB11. A significant region of linkage was also found on 2q35 for LDL (–log10p = 5.59; equivalent LOD score = 4.53). Other interesting regions of linkage included chromosomes 1q32.1, 4p15.1, 5q13.2, 11p14.3 and 18q11.2. Thus, regions were identified by linkage analyses that are likely to harbour genetic risk factors for cardiovascular disease in the analysed Australian population: chromosomes 7p13 (in adults), 6p24 (adolescents), 2q31.1 and 2q35 (in adolescents). Other regions included 1q32.1, 4p15.1, 5q13.2, 11p14.3 and 18q11.2 in adolescents and chromosome 4p13 and Xq26.2–28 in adults. Genome-wide association results for adolescents showed significant evidence of association between total cholesterol at age 14 (p = 8.24x10-7) and rs10503840 on 8p21.1. Such association has not previously been reported. Evidence of differential association across time was also found between HDL and variant rs10492859, located in the intron of the CDH13 gene, consistent with earlier studies on larger datasets. Significant association (p = 2.25x10-6) was also found between rs10507266 on 12q24.21 in an intron of THRAP2, a gene involved in early development of heart and brain, with triglycerides at age 12. Evidence of association was also found between HDL across time and variant rs10492859 on 16q23. Several other “suggestive” potential loci associated with lipid traits at one time point as well as across time were also found. In conclusion, the work described in this thesis establishes the importance of age-specific genetic effects on plasma lipids and lipoproteins, and identifies several regions of highly significant genetic linkage with these phenotypes in either adolescence or adulthood. It is clear that, as well as cross-sectional studies to identify genes affecting CVD risk factors, longitudinal genetic linkage and association studies are needed to assess relative contributions to risk across the lifespan.

Abstract By 2020 the World Health Organisation has predicted that depression will be the largest cause of disease burden in the world (Ellen, 2002). This study investigated the effects of three interventions (Explanatory Style, Conflict Resolution, and Exercise) on the level of well-being of adolescents from the middle years of schooling. The research consisted of three studies. Study 1 involved the design of a Student Perception Questionnaire. The 28¬–item Student Perception Questionnaire was created to measure the outcomes of the three interventions and was trialled on 215 Middle School students. A Principal Components analysis with Varimax rotation was performed on the data retrieved from the respondents, and all items were retained on the questionnaire, although four factors did not show a .30 loading. Study 2, a Pilot Study, was conducted with three students to trial the interventions and measures in preparation for the final study. It included the collection of qualitative and quantitative data. The qualitative data was gained from interviews held with the students, parents, and teachers. Study 2 revealed that the interventions and the measures used to determine the effectiveness of the interventions would be suitable for Study 3. Study 3 was the full intervention that involved 25 students in an intervention group and six students in a no-intervention group. The 25 students were allocated to six groups that were engaged in a counterbalanced design study using the Explanatory Style, Conflict Resolution, and Exercise interventions. The group of six students was used as a comparison group. The results showed that students in the intervention group experienced a reduction of internalising behaviours such as withdrawal and depressive symptoms following all three interventions. The program as a whole was successful in reducing depressive symptoms and the interventions individually also significantly reduced depressive symptoms. The intervention group developed more optimistic thinking styles following the explanatory style intervention. Analysis of parent data revealed that parents of the intervention group were experiencing significant feelings of incompetence and guilt towards themselves as parents. In the members of the no-intervention group, having good social skills and a strong support network of friends and family were protective factors against depressive symptoms. The thesis showed that interventions can be used with adolescents that are effective in reducing depressive symptoms and do not have negative side effects, such as those associated with medications.