Biomedical subjects

Dirk van Kampen

Publications and source records attributed to Dirk van Kampen.

4 recordsLinked to original sources

PubMed2006

The Schizotypic Syndrome Questionnaire (SSQ): Psychometrics, validation and norms.

This paper examines the psychometric properties (reliability and factor structure) and validity (relationship with various self-report measures and SPEM dysfunction) of the SSQ or Schizotypic Syndrome Questionnaire, a 108-item inventory for the measurement of 12 prodromal or schizotypic symptoms present in Van Kampen's model of schizophrenic prodromal unfolding. This paper also provides normative data for the SSQ. The SSQ demonstrates adequate reliability and breaks down into three correlated factors: negative schizotypy, asocial schizotypy and positive schizotypy. Results further attest the construct validity of the instrument. Because of the implications of the SSQ model for the definition of schizophrenia, the instrument's three-dimensional factor structure and the nature of one of the factors are discussed in more detail.

Adult↗

PubMed2006

The Dutch DAPP-BQ: improvements, lower- and higher-order dimensions, and relationship with the 5DPT.

After modifying 53 items in a previous Dutch translation of the Dimensional Assessment of Personality Pathology-Basic Questionnaire (DAPP-BQ; Livesley & Jackson, 2002), the present DAPP-BQ scales (with or without Self-Harm included) were subjected to a principal components analysis with oblimin or varimax rotation in a general population sample of 478 subjects, retaining four factors. All four (higherorder) factors (Emotional Dysregulation, Dissocial, Inhibition, and Compulsivity) proved identical to the factors originally derived in Canada, with Tucker coefficients of factor similarity approaching unity. Particularly the (unexpected) finding that the present Dutch version of the DAPP-BQ also resulted in an Inhibition factor (and not, like the former Dutch version, in an Intimacy Problems factor) was considered positive. In addition, a principal components analysis with oblimin rotation was conducted on the 282 items contained in the 18 DAPP-BQ scales, investigating the lower-order structure of the DAPP-BQ; in this case, 18 factors were retained. Although the structure originally derived by Livesley and colleagues could not be recovered completely, the degree of similarity was of such a magnitude that the 18 DAPP-BQ scales were considered to give a dependable account of the "true" lower-order structure of disordered personality. Moreover, based on the finding that the 18 scales are sufficiently reliable (Cronbach's alpha) and correlate as predicted in a subsample of 284 subjects with the normal personality scales of Van Kampen's 5DPT (or, Five-Dimensional Personality Test), the DAPP-BQ appears to be a valuable instrument.

Adolescent↗

PubMed2005

Pathways to schizophrenic psychosis: a LISREL-tested model of the unfolding of the schizophrenic prodrome.

In this article a literature-based model (the Schizotypic Syndrome Questionnaire [SSQ] model) is presented that gives a description of the temporal unfolding of the schizophrenic prodrome. As a guiding principle for the selection of the symptoms in the model, the hypothesis was held that the main prodromal features determine each other in terms of cause and effect. Furthermore, the developmental pathways between the symptoms were not allowed to be in conflict with the usual observation that negative symptoms precede psychotic-like ones nor--at least in broad outline--with J.P. Docherty, D.P. van Kammen, S.G. Siris, and S.R. Marder's (1978) description of the various onset stages in the development of a schizophrenic psychosis. For the definitive version of the SSQ model, 12 symptoms were selected (e.g., affective flattening, suspicion, and delusional thinking). After specifying the paths to be estimated, the model was examined in two randomly drawn samples from a total community-based sample of 771 normal subjects and in the total sample itself, in each case resulting in adequate fit values. Moreover, all postulated pathways were found to be significantly different from zero. The use of a normal sample was based on the continuum hypothesis. Given the present-day discussions concerning the tenability of the schizophrenia concept, the model's implications with respect to that issue are particularly emphasized. Furthermore, the concept of the schizophrenia prodrome itself is critically discussed.

Adult↗

PubMed2002

The DAPP-BQ in The Netherlands: factor structure and relationship with basic personality dimensions.

After discarding eight items in the Dutch translation of Livesley's DAPP-BQ that showed item-total correlations < 0.20 in a sample of 223 normal subjects. Cronbach's alpha coefficients were calculated for the remaining items in the 18 scales of this instrument. The 'Dutch' alpha coefficients proved to be satisfactory. Furthermore, the Dutch DAPP-BQ scales were factor analyzed, retaining four factors. Three of these factors proved to be identical (Emotional Dysregulation and Dissocial) or nearly identical (Compulsivity) to the Canadian factors. However, the original factor Inhibition was not the same as the remaining Dutch factor Intimacy Problems. In a sample of 115 students, the estimated scores for the Dutch Dimensional Assessment of Personality Pathology-Basic Questionnaire (DAPP-BQ) factors were correlated with the scales of Van Kampen's Four-Dimensional Personality Test. As expected, Emotional Dysregulation was found to correlate with Neuroticism, Dissocial with Insensitivity, and Compulsivity with Orderliness. The Intimacy Problems factor proved to be negatively correlated with Extraversion. The results obtained are embedded in the context of the evidence favoring a dimensional model of personality disorder. Furthermore, Livesley's proposal that separate diagnostic criteria for the existence of a personality disorder must be formulated to supplement the assessment by means of the DAPP-BQ is critically discussed.

Adult↗