Ample research has shown that more household chaos is related to lower parenting quality, but it is yet unknown whether this is a causal relation. This dissertation focuses on two research... Show moreAmple research has shown that more household chaos is related to lower parenting quality, but it is yet unknown whether this is a causal relation. This dissertation focuses on two research questions. The first is whether household chaos has a causal effect on parenting. The second is whether the effect of household chaos on parenting is stronger for parents with certain characteristics, such as high sensory-processing sensitivity (SPS), low self-regulation, and more impulsivity. Two experimental studies were conducted in which household chaos was manipulated. The results show that household chaos affects both positive and negative parenting, but only in demanding parenting situations. Moderation by impulsivity was not found and moderation by SPS and by self-regulation was inconsistent. Regarding SPS, this may exacerbate the effect of household chaos on parenting in case of extreme differences between or high levels of household chaos. Regarding self-regulation, parents with low self-regulation may not have enough self-regulation capacities to simultaneously lower their levels of household chaos and refrain from harsh discipline. These results form a promising vantagepoint for further research, which could eventually lead to prevention and intervention programs to improve parenting by reducing household chaos. Show less
Crack-cocaine dependence is a serious and complex problem with as yet no adequate treatment. The CATCH project was initiated to explore new pharmacological treatment options for crack-cocaine... Show moreCrack-cocaine dependence is a serious and complex problem with as yet no adequate treatment. The CATCH project was initiated to explore new pharmacological treatment options for crack-cocaine dependence in the Netherlands. In three separate parallel-group, randomised controlled, feasibility trials, three promising medications were investigated for their acceptance, efficacy, and safety in the treatment of crack-cocaine dependence: (1) topiramate 200 mg/day, (2) modafinil 400 mg/day, and (3) sustained-release (SR) dexamfetamine 60 mg/day. In our first trial, topiramate was safe and well-tolerated in the sample of crack-cocaine dependent patients, but efficacy was not supported, probably due to low acceptance of the treatment. Acceptance and benefits of modafinil were not demonstrated in our second trial, most likely due to low adherence. However, in a post hoc analysis, substantial cocaine use reductions were found in a high modafinil-adherent subgroup. Our third trial showed that SR dexamfetamine is a well-accepted, effective, and safe agonist treatment for comorbid treatment-refractory cocaine dependence in heroin dependent patients in heroin-assisted treatment. To conclude, our study is an important contribution to the addiction research field, with negative findings pertaining to the efficacy of topiramate, ambiguous findings for modafinil, and promising findings for agonist substitution treatment with SR dexamfetamine. Show less
During early adolescence, there is no association between internalizing behaviour and cannabis use. There is an association between externalizing behaviour and cannabis use, where externalizing... Show moreDuring early adolescence, there is no association between internalizing behaviour and cannabis use. There is an association between externalizing behaviour and cannabis use, where externalizing behaviour precedes cannabis use rather than the other way around. Secondly, during adolescence, there is an association between psychosis vulnerability and cannabis use, where cannabis use predicts psychosis vulnerability and vice versa, suggesting a bi-directional cascading association. Thirdly, during early adolescence, the social skill “self-control” was (unexpectedly) unrelated to cannabis use. Cooperation and assertiveness are associated with cannabis use during this life phase, where higher levels of cooperation decrease the chance of using cannabis and higher levels of assertiveness increase the chance of using cannabis during early adolescence. Cooperation and assertiveness did not differentiate between early and late onset of cannabis use or predict frequency of use. In addition, compared to non-users, cannabis users experience problems only in motivational inhibitory control, not in cognitive inhibitory control. Also, cannabis users experience problems in behavioural impulsivity, which is related to motivational inhibitory control. Lastly, cannabis users have problems with social perception in comparison to non-using controls, particularly when these social perception skills involve emotion recognition. Also, heavy cannabis users experience significantly more psychological problems when they have relatively poor social perception skills. Future research must determine whether the behavioural and cognitive concepts and constructs examined in this thesis in relation to cannabis use should be incorporated in prevention and intervention programs. Show less
Slof-Op't Landt, M.C.T.; Bartels, M.; Middeldorp, C.M.; Beijsterveldt, C.E.M.; Slagboom, P.E.; Boomsma, D.I.; ... ; Meulenbelt, I. 2013
In this thesis, a series of studies on different aspects of the genetics of eating disorders is presented. The heritability of disordered eating behavior and attitudes in relation with body mass... Show moreIn this thesis, a series of studies on different aspects of the genetics of eating disorders is presented. The heritability of disordered eating behavior and attitudes in relation with body mass index (BMI) was evaluated in a large adolescent twin-family sample ascertained through the Netherlands Twin Registry. Furthermore, the association of four candidate genes with anorexia nervosa and eating disorders characterized by self-induced vomiting was tested in a female patient group from the Genetics of Eating Disorder (GenED) study and a female control group from the Netherlands Twin Registry. Subsequently the observed association between the Tryptophan Hydroxylase 2 (TPH2) gene and eating disorders was investigated further. In a group of random controls and a group of patients with an eating disorder it was evaluated if the TPH2 gene was also associated with two potential risk factors for eating disorders: perfectionism and impulsivity. The results shed more light on the relationship between these factors and eating disorders. Show less
