Comorbidity rates between ADHD and anxiety disorders (AD) are high, but little is known about the nature of this co-occurrence. A dominant idea is that AD may intensify some (i.e., attention and... Show moreComorbidity rates between ADHD and anxiety disorders (AD) are high, but little is known about the nature of this co-occurrence. A dominant idea is that AD may intensify some (i.e., attention and working memory) and attenuate other (i.e., inhibition) ADHD symptoms. Results are mixed, potentially because of between-study differences. To investigate this further we performed a meta-regression analysis on 11 studies (n ‘ADHD-only’ = 695; n ‘ADHD + AD’ = 608), containing 35 effect sizes on attention, inhibition and working memory. Main results were: (1) no evidence of a negative effect of AD on attention and working memory; (2) better response inhibition in children with ADHD with AD than those with only ADHD (medium ES g = − .40); (3) medication moderated this association: the effect seemed limited to studies that included medication-naïve participants; (4) the difference between the two groups increased with age for attention and with proportion of boys for working memory ability. There was no effect of comorbid disruptive behavior disorder. In conclusion, AD seems to be a protective factor for inhibition problems as assessed with laboratory tasks in ADHD, especially in children who are medication naïve. Further, AD may have a protective function for attention in older children, and for working memory in boys with ADHD. It is therefore important to screen for AD when diagnosing ADHD, and to educate those with comorbid AD about the possible positive function of feeling anxious. Potential negative effects of ADHD medication on inhibition in children with comorbid AD should be considered. Show less
Self-control abilities are crucial for successful functioning in daily life. At the core of self-control lies the ability to intentionally inhibit one__s actions. Intentional inhibition differs... Show moreSelf-control abilities are crucial for successful functioning in daily life. At the core of self-control lies the ability to intentionally inhibit one__s actions. Intentional inhibition differs from externally driven inhibition in that it is driven by an internal thought process rather than an external stimulus that tells one to stop. The goal of this thesis was to examine the development of intentional inhibition and compare this with externally driven inhibition. In order to investigate the covert process of intentional inhibition, the research described in this thesis made use of neurobiological measures such as phasic heart rate changes and functional magnetic resonance imaging (fMRI). In addition, to learn more about self-control in context, the final empirical chapter examined intentional and externally driven inhibition in the context of relevant and irrelevant emotions. Show less
Core deficits in people with autisme spectrum disorders (ASD) are difficulties in adapting their behaviour to the social environment which hampers the possibilities to communicate adequately and to... Show moreCore deficits in people with autisme spectrum disorders (ASD) are difficulties in adapting their behaviour to the social environment which hampers the possibilities to communicate adequately and to have reciprocal relationships. These problems have a serious impact on functioning in their daily life. Since ASD are severe and lifelong conditions, it is relevant to examine how children with ASD develop troughout their life and to investigate which factors constitute an unfavourable contribution to their development. This thesis reveals that children with ASD are at specific risk of poor quality of life in adulthood when compared to children with other psychiatric disorders. Secondly, the impact of ASD on specific domains of intellectual functioning is different at different ages, implicating that re-evaluation of cognitive function during development of children with ASD is recommended during their life. Thirdly, children with ASD who are at risk of schizophrenia spectrum pathology, may show negative schizotypal symptoms, but also disorganized and positive symptoms in addition to ASD symptomatology. These symptoms of schizotypy appear to be associated with inhibition problems. We should be aware of inhibition problems in children with ASD because they may be indicators of high risk to schizophrenia spectrum pathology later in life. Show less
Sjoerds, Z.; Brink, W. van den; Beekman, A.T.F.; Penninx, B.W.J.H.; Veltman, D.J. 2013
