Although it is common to describe delusions in schizophrenia as 'false beliefs', one of the recent
key questions centers around their so-called 'doxastic' status, i.e., whether or not delusions should
be seen as belief-like in nature. In order to decide this issue, in this study, we aim to empirically
investigate the (non-)doxastic nature of delusional experience in patients diagnosed with a
schizophrenic disorder. Three features of schizophrenic delusions have been identified as relevant
to this project: the degree of (1) cognitive, (2) behavioural and (3) affective circumscription
manifested by delusions.
(1) Cognitive circumscription, i.e., how well delusions are integrated with other beliefs. This we
aim to study cross-sectionally by comparing patients with and without active delusions on the
relation between insight and delusional conviction.
(2) Behavioural circumscription, i.e., how often subjects on the basis of delusions. This we aim to
study longitudinally by examining the relation between phenomenological correlates of delusions
(conviction, preoccupation and systematisation) and acting on delusions.
(3) Affective circumscription, i.e., to what extent subjects display emotional responses which are
congruent with the content of delusions. Here again, we will longitudinally study whether patients
with different delusions defined in terms of delusional content experience different kinds of
emotion.