The question whether executive function (EF) deficits in children are associated with conduct problems remains controversial. Although the origins of aggressive behavior are to be found in early childhood, findings from EF studies in preschool children with aggressive behavior are inconsistent. The current study aimed to investigate whether preschool children with aggressive behavior show impairments in EF. From a population-based sample, 82 preschool children who were showing aggressive behavior as indicated by scores at or above the 93rd percentile on the Aggressive Behavior Scale of the CBCL 1 1/2-5 were selected. These children with aggressive behavior were matched on IQ to a group of typically developing control children (N=99). Six neuropsychological tasks were administered to assess set shifting, inhibition, working memory and verbal fluency. A factor analysis was conducted which yielded one clear factor: inhibition. Aggressive preschool children showed poorer performance on this inhibition factor than control children and boys performed worse on this factor than girls. This association between aggressive behavior and inhibition deficits was maintained after controlling for attention problems. In addition, gender differences in all EFs measured were found with boys exhibiting more impairment in EF than girls. These findings demonstrate that preschool children with aggressive behavior show impairments in inhibition, irrespective of attention problems.

The objective of this study was to test our alternative interpretation of the separation-individuation hypothesis. This interpretation states that separation from the parents is not a precondition for individuation, but rather separation and individuation are two parallel processes of development during adolescence. We investigated our interpretation in two ways. Firstly, we looked at descriptive age differences in parental support and development of relational and societal identity. Secondly, we investigated the variation with age of the associations between parental support and emotional adjustment, and identity and emotional adjustment. Data of a representative Dutch sample of 2814 adolescents, aged 12-24 were used. In both cases, the findings supported our interpretation of the separation-individuation hypothesis and similar results were found in the descriptive analyses and the structural equation models. Parental support decreased with age, and so too did its association with emotional adjustment. In other words, as adolescents become older, they experience less parental support, while its importance for their emotional adjustment also declines. The opposite pattern was observed with respect to identity development: as adolescents become older, their relational and societal identity commitments develop, and the degree to which these commitments are developed also becomes more important for their emotional adjustment. r

Suppressor variables are well known in the context of multiple regression analysis. Using several examples, the authors demonstrate that the different forms of the suppressor phenomenon described in the literature occur not only in prediction equations but also in the explanatory use of multiple regression, including structural equations models. Moreover, they show that the probability of their occurrence is relatively high in models with latent variables, in which the suppressed variable is corrected for measurement errors. Special attention will be paid to the two-wave model since this is particularly liable to the suppressor phenomenon. The occurrence of suppression in structural equations models is usually not foreseen and confronts researchers with problems of interpretation. The authors discuss definitions of the suppressor phenomenon, show how the unwary researcher can be warned against it, and present guidelines for the interpretation of the results.

The aim of the present study is (1) to investigate the impact of patient demands on primary care physicians’ burnout and (2) to examine the stability and change of burnout across time. Participants were drawn from the official Dutch registration system for primary health care, and longitudinal panel data (n= 165) from three waves with a 5‐year time interval were used. They filled in the Maslach Burnout Inventory (MBI) and a validated scale for the assessment of patient demands. The results of various stability and change models that were tested using structural equation modelling (SEM) indicated that demanding patient contacts lead to increased burnout among physicians. In addition, the findings suggested that about one quarter of the variance in physician's actual burnout levels across one decade is accounted for by a stable component, whereas about three quarters is accounted for by a change component. Hence, physician burnout seems to be a rather chronic condition that may be aggravated by exposure to demanding patients.

Researchers and clinicians using Jacobson and Truax's index to assess the reliability of change in patients, or its counterpart by Chelune et al., which takes practice effects into account, are confused by the different ways of calculating the standard error encountered in the literature (see the discussion started in this journal by Hinton-Bayre). This article compares the characteristics of (1) the standard error used by Jacobson and Truax, (2) the standard error of difference scores used by Temkin et al. and (3) an adaptation of Jacobson and Truax's approach that accounts for difference between initial and final variance. It is theoretically demonstrated that the last variant is preferable, which is corroborated by real data. (JINS, 2004, 10, 888-893.)