Paranoia - Entstehungsprozesse und Auswege. Die Rolle von Einsamkeit und sozialkognitiven Mechanismen sowie eine Behandlungskonzeptualisierung zur Therapie paranoiden Wahns.

Delusions are part of the core symptoms of psychosis. Paranoia in particular is one of the most predominant among delusional symptoms in clinical samples (Sartorius et al., 1986) and also highly prevalent in non-clinical individuals (Freeman et al., 2011). Over the past two decades researchers developed a multidimensional definition of paranoia that is based on a continuum between sub-clinical paranoid ideation and severe and bizarre paranoid delusions (T. Lincoln, 2007; Nuevo et al., 2012; van Os et al., 2009). On this basis and in line with bio-psycho-social models of schizophrenia (Nuechterlein & Dawson, 1984; Yank et al., 1993) emotion and cognitive based models of paranoia were developed (Freeman et al., 2002; Freeman & Garety, 2014; Kuipers et al., 2006). The statute, that delusions were unalterable with methods of psychotherapy (Jaspers, 1913) could be rejected in favor of scientific proof for psychological predictors of paranoia and thus create a basis for cognitive-behavioral therapy and its interventions. Several studies showed a high prevalence of loneliness in individuals with psychosis (Meltzer et al., 2013; Sündermann et al., 2014), but a causal influence could not be proven. Individuals with psychosis often perceive rejection or stigma (Gras et al., 2014; Switaj et al., 2013; Yang et al., 2013) that could trigger loneliness and thus paranoia. Based on the cognitive models of paranoia (Freeman et al., 2002; Garety & Freeman, 2013) and the conceptualizations of loneliness (Mikulincer & Segal, 1990; Schwab, 1997) the present dissertation investigated loneliness as a possible additional etiological factor in the formation of paranoia. To proof causality, the first study of this dissertation experimentally manipulated loneliness and assessed the impact on paranoia. This study was a first causal proof for the impact of experimentally induced or reduced loneliness on paranoia. Additionally a moderator effect of proneness to psychosis on the relation between loneliness and paranoia was assessed. In individuals more prone towards paranoia a reduction of loneliness had a larger effect on a decrease in paranoia than in low prone individuals. Study II focused on the mechanisms involved in the relation between loneliness and paranoia in a clinical sample. The hypothesized mediator-effect of negative schemata on other persons could be proven and showed a fully mediation on the relation between loneliness and paranoia. As an evidence based intervention cognitive behavioral therapy for psychosis was included in national therapy guidelines for schizophrenia spectrum disorders (Gaebel et al., 2006; National Collaborating Centre for Mental Health, 2014), however the implementation of cognitive behavioral therapy concepts seems to be insufficient (Bechdolf & Klingberg, 2014; Haddock et al., 2014), although British pilot-studies showed promising effectiveness of cognitive behavioral interventions on psychiatric acute wards (Durrant et al., 2007; Haddock et al., 1999). Negative affect showed to be strongly associated with paranoia and was included as a mediator in the cognitive models on paranoia (Freeman et al., 2002; Fusar-Poli et al., 2014; Garety & Freeman, 2013; Smith et al., 2006). With regard to the cognitive model of paranoia and findings of earlier intervention studies a manualized mood-stabilizing cognitive behavioral therapy concept (Mehl, 2013) was tested in a pre-post design in study III. This study had a focus on the implementation of the concept in an acute ward of a local psychiatry under normal conditions and on testing the effectiveness of mood stabilizing interventions on delusions. Positive symptoms and delusions reduced significantly with large effect sizes and with clinical relevance in a majority of the cases. With regard to the subscales, delusional distress and preoccupation decreased with the largest effect sizes. Furthermore, depressive symptoms reduced significantly with large effect-sizes. Additionally, the concept of the present pre-post study could be implemented in the into the therapeutic standard procedure of the acute ward, to further test effectiveness in randomized controlled studies. The findings support the important role of loneliness in the formation of paranoid ideation and enlighten the relevance of interpersonal cognitive processes, involved in this relation. Furthermore, mechanisms and implications for future research and therapy are discussed. The results of the mood stabilizing intervention further emphasize the relevance of a better implementation of effective cognitive behavioral interventions for patients with psychosis on acute wards. Implications for research, clinical practice and possible adaptations of the program are derived on basis of the findings.