The co-occurrence of depression and anxiety with alcohol use disorders

Penninx, B.W.J.H. [Promotor]Brink, W. van den [Promotor]Beekman, A.T.F. [Promotor]Vogelzangs, N. [Copromotor

School performance in adolescents: An educational neuropsychology perspective

Jolles, J. [Promotor]Krabbendam, A.C. [Promotor

The relation between executive functions and school performance in healthy adolescents

Boschloo, A., Krabbendam, L., De Groot, R., & Jolles, J. (2012, April). The relation between executive functions and school performance in healthy adolescents. Poster presented at the Development of executive functions workshop, Utrecht, The Netherlands.How well do executive function tests and questionnaires predict school performance in healthy adolescents? This was investigated in 173 healthy adolescents aged 12-­18 years who study at pre-university education level (in Dutch: vwo). Executive functions were measured with the D-­KEFS subtests Sorting Test and Tower Test, and with the BRIEF-­SR. School performance was measured with end of term grades for Dutch, English and mathematics

Differential associations of specific depressive and anxiety disorders with somatic symptoms

AbstractObjectivePrevious studies have shown that depressive and anxiety disorders are strongly related to somatic symptoms, but much is unclear about the specificity of this association. This study examines the associations of specific depressive and anxiety disorders with somatic symptoms, and whether these associations are independent of comorbid depressive and anxiety disorders.MethodsCross-sectional data were derived from The Netherlands Study of Depression and Anxiety (NESDA). A total of 2008 persons (mean age: 41.6years, 64.9% women) were included, consisting of 1367 patients with a past-month DSM-diagnosis (established with the Composite International Diagnostic Interview [CIDI]) of depressive disorder (major depressive disorder, dysthymic disorder) and/or anxiety disorder (generalized anxiety disorder, social phobia, panic disorder, agoraphobia), and 641 controls. Somatic symptoms were assessed with the somatization scale of the Four-Dimensional Symptom Questionnaire (4DSQ), and included cardiopulmonary, musculoskeletal, gastrointestinal, and general symptoms. Analyses were adjusted for covariates such as chronic somatic diseases, sociodemographics, and lifestyle factors.ResultsAll clusters of somatic symptoms were more prevalent in patients with depressive and/or anxiety disorders than in controls (all p<.001). Multivariable logistic regression analyses showed that all types of depressive and anxiety disorders were independently related to somatic symptoms, except for dysthymic disorder. Major depressive disorder showed the strongest associations. Associations remained similar after adjustment for covariates.ConclusionThis study demonstrated that depressive and anxiety disorders show strong and partly differential associations with somatic symptoms. Future research should investigate whether an adequate consideration and treatment of somatic symptoms in depressed and/or anxious patients improve treatment outcomes

Development and standardization of a mutagenicity test system using Aspergillus nidulans as test organism

The suitability of Aspergillusnidulans as a test organism for mutagenicity testing has been investigated. Several test systems have been tried. Those systems were preferred in which the mutants or recombinants could be selected without the need of adding a compound to the medium which itself is genetically active.Four incubation methods have been compared. The plate incorporation assay (method 1) is the easiest method for testing chemical compounds, but it is often difficult to obtain reliable quantitative data. Moreover, complications may arise when the compound is toxic or causes a selective advantage of the mutants. In the liquid suspension test (method 2) the conditions can be controlled more accurately, so this method is more suitable for obtaining reliable quantitative data. For testing germinating conidia, the suspension test (method 3) turned out to be less suitable, since some conidia germinated directly from the start causing - in spite of the presence of 0.2% agar - big clumps of conidia at the end of the incubation period. Germinating conidia (and growing mycelium) can better be tested with the media mediated assay (method 4). However, an extra control experiment must be performed in order to discriminate between a real mutagenic activity and a selective advantage.Strain 110, which carries the methGl allele, proved to be very suitable for measuring the point mutation frequency when methionine independent suppressor mutants are scored. The instability of a duplication strain can be also used as an indication for the genetic activity of a chemical compound. The construction of a duplication strain heterozygous for the recessive sorA2 allele (strain 007) reduced the number of plates needed for the scoring of segregants. The exact process by which the sectors arise is not known. Some crossing-over products are scored as deletion products when no special attention ispaid to the morphology of the segregants.For determining the crossing-over and non-disjunction frequencies scoring of mitotic segregation is the easiest way, at least when it is not intended to distinguish the inducing processes. If such a distinction is required, it is easier to select the recombinants. Strain D4 can be used to select recombinants homozygous for the suAladE20 allele, and the crossing-over and non-disjunction products can be directly distinguished by their conidial colour. In practice, complications arose since the conidial colour was faint and the leaky growth of the test strain led to a concentration effect. Selection of sorbose resistant recombinants was even less suitable, and a combinated selection of sorbose resistant and adenine prototroph recombinants proved unfeasible. Selection of pimaricin resistant recombinants of strain D7 was much easier and therefore preferably used in this study. However, since pimaricin itself is known to induce non-disjunctions this system has only been used in combination with the media mediated assay to minimize the risk of complications.The system for measuring the frequency of recessive lethals developed by Morpurgo et al. (1978) has also been investigated, but the background in the control was relatively high. This was most likely caused by incomplete haploidization on FPA medium. Changing the medium did hardly improve the results. This implies that one can only measure larger effects on the frequency of recessive lethals.Several chemicals, mostly with known mutagenic properties have been tested by means of the proposed test systems. These confirmed the suitability of the test systems.Thus, in addition to other mutagenicity tests like the Ames test with bacteria, the fungus Aspergillusnidulans offers good opportunities to asses the genetic activity of chemical compounds on eucaryotic organisms.</p

Academic motivation mediates the influence of temporal discounting on academic achievement during adolescence

Lee, N. C., Krabbendam, L., Dekker, S. J., Boschloo, A. M., De Groot, R. H. M., & Jolles, J. (2012). Academic motivation mediates the influence of temporal discounting on academic achievement during adolescence. Trends in Neuroscience and Education, 1(1), 43-48.This study used a large sample (N=638) of 12-18 year old adolescents to investigate the relationship between academic achievement and temporal discounting, a behavioural measurement of delay of gratification abilities. Neuroscience studies have demonstrated development during adolescence of the areas of the brain involved in delaying immediate gratification in order to achieve long-term goals. This finding may have important consequences for educational practice, as students are frequently required to forsake attractive short-term rewards in favour of less attractive academic long-term alternatives. Results showed that adolescents with an increased ability to delay gratification achieved higher grades then those less able to delay gratification. This relationship was mediated by academic motivation, showing that the effect of delayed gratification abilities on grades was most effective when academic motivation was high. Our results show that the ability to delay gratification may be an individual difference variable that distinguishes high achieving students from their peers. It also highlights that understanding the development of neurocognitive processes can provide a valid contribution to understanding ways in which we can influence academic success

Dominant Goal Orientations Predict Differences in Academic Achievement during Adolescence through Metacognitive Self-Regulation

This study investigated whether academic achievement was predicted by the goal which generally drives a student’s learning behaviour. Secondly, the role of metacognitive self-regulation was examined. The dominant goal orientation was assessed using a new method. 735 adolescents aged 10-19 years read vignettes of students that reflect four goal orientations. Participants indicated which student they resembled most, which revealed their dominant goal orientation. Age, sex and level of parental education were controlled for. Results showed that students with motivation goals of the mastery and performance-approach types obtained higher grades than students characterized by the performance-avoidance and work-avoidance goal type. A mediation analysis showed that goal orientations predicted achievement through the level of metacognitive self-regulation. Intrinsically motivated students showed the best metacognitive self-regulation skills of all students, whereas work-avoidant students had the lowest level of self-regulation skills. The scores of students with performance goals fell in-between. The research showed that the higher grades obtained by performance-approach students, compared to performance-avoidant and work-avoidant students, can partially be explained by their higher levels of metacognitive self-regulation. Thus, goal orientation predicted achievement differences through metacognitive self-regulation skills. This suggests that intrinsic motivation and self-regulation skills should ideally be supported in the classroom. Furthermore, it suggests that teachers could use vignettes to distinguish different types of students in order to identify students who are vulnerable to lower academic achievement