Krankheitseinsicht, dynamisch getestete Exekutivfunktionen und ...

Abstract
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Einleitung
Objective: Lack of insight into illness is common in patients with schizophrenia diagnoses. It is
supposed to reflect deficits of executive functioning that are frequently assessed with the
Wisconsin Card Sorting Test. Studies on the remediability of WCST deficits in schizophrenia,
however, raise doubts about its construct validity and suggest the use of a dynamic pretesttraining-posttest
paradigm (WCSTdyn) and single-case analysis (Reliable Change Index, RCI) in
studies on insight. Moreover, a multifactorial and differential etiology with neurocognitive and
motivational factors, as suggested by STARTUP’s (1996) model, has to be taken into consideration.
The model hypothesizes a quadratic function of the relationship between insight and
cognition, which means that both cognitively impaired and cognitively intact patients with low
insight are to be expected.
Method: Three interrelated studies on WCSTdyn and insight were conducted. In study 1, the
split-half reliability of the WCST-128 was investigated in a non-psychiatric sample (N = 110).
Study 2 compared different RCI single-case tests of significance of intraindividual change on
data from N = 400 patients with schizophrenia diagnoses. Furthermore, a typology with three
homogenous subgroups was developed and first steps toward an external validation were taken.
In study 3, the three types of test-takers were compared on two measures of insight (Item G12 of
the Positive and Negative Syndrome Scale [PANSS]; Osnabrueck Scale of Therapeutic
Attitudes and Identification of Psychological Problems in Schizophrenia [OSSTI: KRUPA,
2005]). The model by STARTUP (1996) was tested with regression and cluster analyses including
scales on coping (Freiburg Questionnaire of Coping with Illness, FKV: MUTHNY, 1989) and
defensiveness (Eppendorf Schizophrenia Inventory, ESI-FR: MAß, 2001; N = 85).
Results: The WCST-64 was sufficiently stable (rtt = .70 [Total Number Correct]). Concordances
of different RCI methods were high (κ = .72 - .90). 45 % of the sample consisted of high scorers,
in 43 % a low initial score could be normalized by a short training intervention (learners), and in
only 12 % of the sample the WCST deficits were not amenable to training (nonlearners). Insight
of nonlearners was significantly reduced (G12: g = 0,45). Finally, three clusters were identified
with configurations of insight and WCSTdyn scores consistent with the prediction by STARTUP
(1996). Patients with intact neurocognition but low insight responded in a significantly more
defensive manner (g = 0,38). They did not differ in self-rated coping, however. A quadratic
relationship could not be confirmed.
Conclusion: The RCI-based performance typology developed in studies 1 and 2 is a universally
applicable analytic tool for future studies on insight-limiting neurocognitive deficits with the
WCSTdyn. Results from study 3 point in the direction of a multifactorial etiology of lack of
insight in schizophrenia with differential contributions of neurocognitive deficits (e.g., interference
control) and defensiveness.