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Dive into the research topics where Laurence Claes is active.

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Featured researches published by Laurence Claes.


Child and Adolescent Psychiatry and Mental Health | 2012

International prevalence of adolescent non-suicidal self-injury and deliberate self-harm.

Jennifer J. Muehlenkamp; Laurence Claes; Lindsey Havertape; Paul L. Plener

BackgroundThe behaviours of non-suicidal self-injury (NSSI) and deliberate self-harm (DSH) are prevalent among adolescents, and an increase of rates in recent years has been postulated. There is a lack of studies to support this postulation, and comparing prevalence across studies and nations is complicated due to substantial differences in the methodology and nomenclature of existing research.MethodsWe conducted a systematic review of current (2005 - 2011) empirical studies reporting on the prevalence of NSSI and DSH in adolescent samples across the globe.ResultsFifty-two studies fulfilling the inclusion criteria were obtained for analysis. No statistically significant differences were found between NSSI (18.0% SD = 7.3) and DSH (16.1% SD = 11.6) studies. Assessment using single item questions led to lower prevalence rates than assessment with specific behaviour checklists. Mean prevalence rates have not increased in the past five years, suggesting stabilization.ConclusionNSSI and DSH have a comparable prevalence in studies with adolescents from different countries. The field would benefit from adopting a common approach to assessment to aide cross-cultural study and comparisons.


Clinical Psychology Review | 2009

Gray's Reinforcement Sensitivity Theory as a framework for research on personality–psychopathology associations

Patricia Bijttebier; Ilse Beck; Laurence Claes; Walter Vandereycken

Grays Reinforcement Sensitivity Theory (RST) presupposes individual differences in the sensitivity of basic brain systems that respond to punishing and reinforcing stimuli. These differences are thought to underlie the personality dimensions of anxiety and impulsivity, and to have relevance for psychopathology. The present article aims at reviewing RST-based research on personality-psychopathology associations. First, RST and its revisions are described and the link between RST systems and personality dimensions is discussed. Second, studies investigating associations between RST systems and specific types of psychopathology are summarized. Although the available research yields a rather consistent picture with respect to constellations of BIS/BAS sensitivity that are associated with specific types of psychopathology, it also provides a clear indication that much work remains to be done. The discussion section highlights several topics that deserve future research attention.


Assessment | 2010

Assessing the affective features of psychopathy in adolescence: a further validation of the inventory of callous and unemotional traits.

Annelore Roose; Patricia Bijttebier; Stefaan Decoene; Laurence Claes; Paul J. Frick

To provide an extended assessment of the affective features of psychopathy, Frick developed the Inventory of Callous and Unemotional Traits (ICU), which is a multi-informant questionnaire. Previous studies have provided initial support for the self-report version. The aim of the present study is to investigate the validity of self- as well as other report versions of the ICU and examine associations with measures of psychopathic traits, empathy, antisocial behavior and prosocial attitudes, reward and punishment sensitivity, and personality traits in a Dutch community sample of 455 adolescents (56% males). The results of the present study replicate and extend previous findings on the psychometric properties and the validity of the ICU in a sample of nonreferred youth. The three ICU subscales showed distinctive patterns of associations with key external criteria. Implications and directions for future research are discussed.


Comprehensive Psychiatry | 2010

The affect-regulation function of nonsuicidal self-injury in eating-disordered patients: which affect states are regulated?

Laurence Claes; E. David Klonsky; Jennifer J. Muehlenkamp; Peter Kuppens; Walter Vandereycken

This study examines the affect regulation function of different types of nonsuicidal self-injury (NSSI) in 177 female eating-disordered inpatients. Almost 45% of the eating-disordered patients displayed at least 1 type of NSSI. Cutting and scratching were the most common forms of NSSI followed by bruising and burning oneself. For all types of NSSI except bruising, the affect regulation function was most strongly endorsed. Affect states reported to precede and follow NSSI were also examined to determine the particular affect states regulated by NSSI. In general, positively valenced low-arousal affect states increased and negatively valenced high-arousal affect states decreased from before to after NSSI. Finally, affective changes associated with NSSI were related to different NSSI characteristics, indicating that the increase in positive affect after NSSI is significantly related to the frequency of NSSI and the numbers of functions reported for NSSI. Theoretical and treatment implications are discussed.


Pediatric Blood & Cancer | 2009

Adjuvant dendritic cell-based tumour vaccination for children with malignant brain tumours

Hilko Ardon; Steven De Vleeschouwer; Frank Van Calenbergh; Laurence Claes; Christof M. Kramm; Stefan Rutkowski; Johannes Wolff; Stefaan Van Gool

A large experience with dendritic cell (DC)‐based vaccination for malignant brain tumours has been gained in adults. Here we focus on the results obtained in children with relapsed malignant brain tumours.


Journal of Adolescence | 2010

Brief report: The association between non-suicidal self-injury, self-concept and acquaintance with self-injurious peers in a sample of adolescents

Laurence Claes; Adinda Houben; Walter Vandereycken; Patricia Bijttebier; Jennifer J. Muehlenkamp

The current study investigated the association between non-suicidal self-injury (NSSI), self-concept and acquaintance with NSSI peers in a sample of 150 high school students (60% female) with a mean age of 15.56 (SD=2.00) years. Analyses showed that students with NSSI rated themselves lower on academic intelligence, physical attractiveness, social skills and emotional stability than their non-NSSI peers. The self-injurers also had more friends who engaged in NSSI, and having more NSSI acquaintances was negatively related to self-esteem. It could be that adolescents with lower self-esteem are more attracted to self-injuring peers, or that adolescents with low self-esteem are more vulnerable to copy NSSI to deal with their problems or to gain a certain identity in their peer group. Future studies must test these possible NSSI pathways.


Personality and Individual Differences | 2002

Impulsive and compulsive traits in eating disordered patients compared with controls

Laurence Claes; Walter Vandereycken; Hans Vertommen

Abstract The question whether bulimia nervosa (BN) patients show more impulsive and less compulsive traits than anorexia nervosa (AN) patients has been linked to the idea of eating disorders belonging to the so-called obsessive-compulsive spectrum disorders. In this study we have compared both impulsive and compulsive traits in three subgroups of eating disordered patients (total n =56) and a control group of 102 female students. Information about impulsive and obsessive-compulsive traits were gathered by means of standardised self-rating scales. BN and bingeing-purging AN patients reported more impulsive and obsessive traits than restrictive AN patients and controls without eating disorders, although these traits were also present in the latter groups. The data support the hypothesis that obsessive-compulsive and impulsive traits are not mutually exclusive but can be found in groups of individuals with the same diagnosis or even within the same individual.


The New England Journal of Medicine | 2015

Pediatric Outcome after Maternal Cancer Diagnosed during Pregnancy.

Frédéric Amant; Tineke Vandenbroucke; Magali Verheecke; Monica Fumagalli; Michael Halaska; Ingrid A. Boere; Sileny Han; Mina Mhallem Gziri; Fedro Peccatori; Lukas Rob; Christianne Lok; Petronella O. Witteveen; Jens Uwe Voigt; Gunnar Naulaers; Lore Vallaeys; Frank Van den Heuvel; Lieven Lagae; Luc Mertens; Laurence Claes; Kristel Van Calsteren

BACKGROUND Data on the long-term outcome of children who are exposed to maternal cancer with or without treatment during pregnancy are lacking. METHODS In this multicenter case-control study, we compared children whose mothers received a diagnosis of cancer during the pregnancy with matched children of women without a cancer diagnosis. We used a health questionnaire and medical files to collect data regarding neonatal and general health. All children were prospectively assessed (by means of a neurologic examination and the Bayley Scales of Infant Development) at 18 months, 36 months, or both. A cardiac assessment was performed at 36 months. RESULTS A total of 129 children (median age, 22 months; range, 12 to 42) were included in the group whose mother had cancer (prenatal-exposure group) with a matching number in the control group. During pregnancy, 96 children (74.4%) were exposed to chemotherapy (alone or in combination with other treatments), 11 (8.5%) to radiotherapy (alone or in combination), 13 (10.1%) to surgery alone, 2 (1.6%) to other drug treatments, and 14 (10.9%) to no treatment. Birth weight was below the 10th percentile in 28 of 127 children (22.0%) in the prenatal-exposure group and in 19 of 125 children (15.2%) in the control group (P=0.16). There was no significant between-group difference in cognitive development on the basis of the Bayley score (P=0.08) or in subgroup analyses. The gestational age at birth was correlated with the cognitive outcome in the two study groups. Cardiologic evaluation among 47 children at 36 months of age showed normal cardiac findings. CONCLUSIONS Prenatal exposure to maternal cancer with or without treatment did not impair the cognitive, cardiac, or general development of children in early childhood. Prematurity was correlated with a worse cognitive outcome, but this effect was independent of cancer treatment. (Funded by Research Foundation-Flanders and others; ClinicalTrials.gov number, NCT00330447.).


European Psychiatry | 2015

Systematic review and meta-analysis of prevalence studies in transsexualism.

Jon Arcelus; Walter Pierre Bouman; W. Van Den Noortgate; Laurence Claes; Gemma L. Witcomb; Fernando Fernández-Aranda

BACKGROUND Over the last 50 years, several studies have provided estimates of the prevalence of transsexualism. The variation in reported prevalence is considerable and may be explained by factors such as the methodology and diagnostic classification used and the year and country in which the studies took place. Taking these into consideration, this study aimed to critically and systematically review the available literature measuring the prevalence of transsexualism as well as performing a meta-analysis using the available data. METHODS Databases were systematically searched and 1473 possible studies were identified. After initial scrutiny of the article titles and removal of those not relevant, 250 studies were selected for further appraisal. Of these, 211 were excluded after reading the abstracts and a further 18 after reading the full article. This resulted in 21 studies on which to perform a systematic review, with only 12 having sufficient data for meta-analysis. The primary data of the epidemiological studies were extracted as raw numbers. An aggregate effect size, weighted by sample size, was computed to provide an overall effect size across the studies. Risk ratios and 95% confidence intervals (CIs) were calculated. The relative weighted contribution of each study was also assessed. RESULTS The overall meta-analytical prevalence for transsexualism was 4.6 in 100,000 individuals; 6.8 for trans women and 2.6 for trans men. Time analysis found an increase in reported prevalence over the last 50 years. CONCLUSIONS The overall prevalence of transsexualism reported in the literature is increasing. However, it is still very low and is mainly based on individuals attending clinical services and so does not provide an overall picture of prevalence in the general population. However, this study should be considered as a starting point and the field would benefit from more rigorous epidemiological studies acknowledging current changes in the classification system and including different locations worldwide.


Archives of Suicide Research | 2011

Non-Suicidal and Suicidal Self-Injurious Behavior among Flemish Adolescents: A Web-Survey

Imke Baetens; Laurence Claes; Jennifer J. Muehlenkamp; Hans Grietens; Patrick Onghena

The present study investigated the prevalence of non-suicidal self-injury (NSSI) and suicidal self-injury (SSI) in a sample of 1,417 Flemish adolescents aged 12 to 18, as well as psychosocial differences between adolescents engaging in NSSI and adolescents engaging in SSI. Participants completed an anonymous online survey inquiring about NSSI and SSI functions, sociodemographic correlates, help seeking behaviors, and stressful life events. Lifetime prevalence of NSSI was 13.71% and SSI was 3.93%. No gender or age differences appeared between adolescents engaging in NSSI or SSI; however, differences in educational level were observed. Significant differences in functions of the behavior and number of stressful life events were noted between groups. Finally, the likelihood of receiving professional help differed between adolescents engaging in NSSI and adolescents engaging in SSI. Implications of the findings for assessment and treating NSSI and SSI are discussed.

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Dive into the Laurence Claes's collaboration.

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Patricia Bijttebier

Catholic University of Leuven

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Dirk Smits

Katholieke Universiteit Leuven

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Walter Vandereycken

Katholieke Universiteit Leuven

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Koen Luyckx

Katholieke Universiteit Leuven

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Guido Pieters

Katholieke Universiteit Leuven

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Glenn Kiekens

Katholieke Universiteit Leuven

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Imke Baetens

Vrije Universiteit Brussel

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