Four theoretical models have been postulated in formation and maintenance of delusional idea in schizophrenia:

1. 1. Cognitive biases (attentional bias, jumping-to-conclusion, need-for-clousure, attributional bias),

2. 2. Social cognition alterations (theory-of-mind, emotion facial recognition),

3. 3. Perceptive alterations of anomalous experiences and

4. 4. Emotional anomalies (anxiety, depression, self-esteem, “self” discrepancies).

To exam the joint influence of these anomalies in delusional activity in DD.

We studied the delusional activity measured by the “Maudsley Assessment of Delusion Schedule” in 68 patients with DD (n=68) diagnosed by SCID-I (DSM-IV-TR). Cognitive biases were evaluated by “Emotional Stroop”, “Experimental Beads Task”, “Need-for-Closure Scale”, “Internal, Personal and Situational Attributions Questionnaire”. Social cognition alterations were measured by Faux-pas Task and Eyes-Test; perceptive alterations by “Cardiff Anomalous Perceptions Scale”; and emotional anomalies by “Hamilton Anxiety Rating Scale”, “Beck Depression Inventory”, “Rosenberg Self-esteem Scale” and “Personal Qualities Questionnaire”. The relationship between delusional activity and these cognitive anomalies were examined using lineal regression models controlled by socio-demographic characteristics, premorbid IQ (“NART”), negative symptomatology (“PANSS”) and neuropsychological function (attention, verbal learning, working memory and executive function).

High scores in delusion activity were significantly associated with high scores in jumping-to-conclusion and depression and low scores in faux-pas and self-esteem, after being adjusted by number of studied years and negative symptomatology.

Cognitive biases (jumping-to-conclusions), social cognition deficit (faux-pas) and emotional alterations are the most implicated anomalies in formation and maintenance of delusional idea in DD.